The Nitrogen Bomb – fossil-fueled fertilizers keep 5.5 billion people alive

Fisher, D. 4 April 2001. Discover magazine Vol. 22 No. 4 

The Nitrogen Bomb. By learning to draw fertilizer from a clear blue sky, chemists have fed the multitudes.

They’ve also unleashed a fury as threatening as atomic energy.

In 1898, Sir William Crookes called on science to save Europe from impending starvation. The world’s supply of wheat was produced mainly by the United States and Russia, Sir Crookes noted in his presidential address to the British Association for the Advancement of Science. As those countries’ populations grew, their own demands would outpace any increase in production. What then would happen to Europe? “It is the chemist who must come to the rescue of the threatened communities,” Crookes cried. “It is through the laboratory that starvation may ultimately be turned into plenty.”

The crux of the matter was a lack of nitrogen. By the 1840s agricultural production had declined in England, and famine would have ensued if not for the discovery that the limiting factor in food production was the amount of nitrogen in the soil. Adding nitrogen in the form of nitrate fertilizer raised food production enough to ward off disaster. But now, at the end of the century, the multiplying population was putting a new strain on agriculture. The obvious solution was to use more fertilizers. But most of the world’s nitrate deposits were in Chile, and they were insufficient. Where would the additional nitrogen come from?

That question, and Crookes’s scientific call to arms, would trigger a chain reaction as far-reaching as the ones unleashed at Los Alamos four decades later. Historians often describe the discovery of nuclear power as a kind of threshold in human history— a fire wall through which our culture has passed and cannot return. But a crossing every bit as fateful occurred with research on nitrogen. Like the scientists of the Manhattan Project, those who took up Crookes’s challenge were tinkering with life’s basic elements for social rather than scientific reasons. And like the men who created the atomic bomb, they set in motion forces beyond their control, forces that have since shaped everything from politics to culture to the environment.

Today nitrogen-based fertilizers help feed billions of people, but they are also poisoning ecosystems, destroying fisheries, and sickening and killing children throughout the world. In ensuring our supply of food, they are wreaking havoc on our water and air.

Nitrogen is essential to the chemistry of life and, sometimes, its destruction. It winds its way through all living things in the form of amino acids— which are chains or rings of carbon atoms attached to clusters of nitrogen and hydrogen atoms— and it is the primary element of both nitroglycerin and trinitrotoluene, or TNT.

Nitrogen-based fertilizer is now so common, and the chemistry of explosives so well known, that any serious fanatic can make a bomb. The Alfred P. Murrah Federal Building in Oklahoma City was blown up in 1995 with nitrate fertilizer sold in a feed store, combined with fuel oil and a blasting cap.

Nearly 80 percent of the world’s atmosphere is made up of nitrogen— enough to feed human populations until the end of time. But atmospheric nitrogen is made up of extremely stable N2 molecules that are reluctant to react with other molecules. Bacteria convert some atmospheric nitrogen first into ammonia (NH3), then into nitrites (NO2- ) and nitrates (NO3- ), but not nearly enough for modern agriculture. What was needed by the end of the 19th century was a way of imitating these microbes— of “fixing” atmospheric nitrogen into a chemically active form.

A few years before William Crookes gave his speech, lime and coke were successfully heated in an electric furnace to produce calcium carbide, which then reacted with atmospheric nitrogen. Crookes himself had shown that an electric arc can “put the air on fire,” as he described it, oxidizing the nitrogen into nitrates. But the electricity needed for either process was prohibitively expensive. Crookes suggested the use of hydroelectric power, but only Norway had sufficient hydroelectric power, and although the Norwegians constructed a nitrogen-fixation plant, it furnished barely enough nitrogen for domestic use. The rest of Europe still faced the specter of hunger. Into this disquieting scene stepped Fritz Haber.

Haber was a young German physical chemist who renounced his Judaism to enhance his career: Academic opportunities in Germany, as in most other European countries, were limited for Jews at that time. Haber’s first academic appointment after receiving his Ph.D. was as a porter, or janitor, in the chemistry department at the University of Karlsruhe. But he soon talked his way into a lectureship, and in 1898 he was appointed professor extraordinarius and was ready to begin thinking about the problem of nitrogen.

Haber began by considering the possibility of converting atmospheric nitrogen to ammonia directly by reacting it with hydrogen. Previous experimenters had found that the reaction would take place only at high temperatures— roughly 1,000 degrees Celsius— at which ammonia was known to break down instantly. But Haber’s own experiments confirmed that he could transform only about 0.0048 percent of the nitrogen into ammonia in this way. Moreover, a comprehensive investigation of thermodynamic theory confirmed what he had long suspected: that ammonia could be produced in large quantities only under high pressure— higher than was then attainable, but not impossibly high. The problem now became one of finding the right balance between pressure and temperature to get the best results, and of finding a catalyst that might allow the pressures to be brought just slightly back down into the realm of commercial possibility.

After a long search Haber found the element uranium to be just such a catalyst, and with a few further technical refinements he was able to produce nearly half a liter of ammonia an hour. Best of all, the process required little energy, and this obscure metal, having no other commercial use, was cheap.

The company Badische Anilin-& Soda-Fabrik (BASF) sent the chemist Alwin Mittasch and the engineer Carl Bosch to Haber’s laboratory for a demonstration. And, of course, everything went wrong. Haber begged them to stay while he fiddled with the apparatus. Time went by, and Bosch left. Then, just as Mittasch was preparing to leave, the ammonia began to drip out of the tubing. Mittasch stood and stared, and then sat down again, deeply impressed. By the time he left, the ammonia was flowing freely.

It took another three years for the company’s engineers, led by Bosch, to scale up the experiment to commercial levels, but by 1912 the Haber-Bosch process was a viable means of producing fertilizer. Haber and Bosch would later receive Nobel prizes for their efforts, the threat of famine was averted, and the world lived happily ever after. Well, not quite.

Kaiser Wilhelm II’s Germany in the early 1900s was the most powerful state in Europe, with the strongest army, the greatest industrial capacity, and a patriotic fervor to match. The Germans wanted their “rightful place” in the world order, yet their country could not grow except at the expense of someone else’s borders. Nor could Germany fulfill her ambitions through colonization— most of the undeveloped world had already been claimed.

With no room to grow, or even stretch, the kaiser’s fancy turned to thoughts of war. Three inhibitions, however, held him back. The first was the problem of nitrogen for fertilizer, since in these first years of the century Haber had not yet begun his work. Germany was the world’s largest importer of Chilean nitrates, and without a constant infusion of fertilizer, its poor, sandy soils got worse every year. The second problem was again lack of nitrogen, this time for explosives. The third problem was Britain’s Royal Navy, which ruled the seas. If Germany were to start a war, the Royal Navy would cut off its supply of nitrates from Chile, and the population would slowly starve while the armed forces ran out of explosive shells and bombs.

How wonderful for the kaiser, then, was Fritz Haber’s invention of industrial nitrogen fixation. In one stroke Germany would be able to produce all the fertilizer and explosives it needed— provided the war didn’t last too long. In 1913 the first nitrogen-fixing plant began operations at Oppau. A year later, Austria’s heir to the throne, Archduke Franz Ferdinand, was assassinated in Sarajevo. Germany soon pushed Austria to declare war and loosed its own troops both east and west.

World War I ended four years later with the establishment of Soviet Russia and the collapse of Germany, leading directly to the rise of Nazism with all its horrors and to World War II. None of this could have come about without the discovery of commercial nitrogen fixation. In trying to save Europe, Fritz Haber came close to destroying it.

And in trying to feed humankind, we may yet starve it. Civilization’s bloodiest century, sent on a rampage by nitrogen’s emancipation, has passed into history. But the paradox of nitrogen remains. First it was all around us and we couldn’t use it. Now we know how to use it, and it’s suffocating us.

The planet’s 6 billion humans (and counting) rely more than ever on fertilizer to augment the natural nitrogen in soils. In fact, we now produce more fixed nitrogen, via a somewhat modified Haber-Bosch process, than the soil’s natural microbial processes do. Farmers tend to apply more fertilizer rather than take a chance on less, so more nitrogen accumulates than the soil can absorb or break down. Nitrates from automobile exhaust and other fossil-fuel combustion add appreciably to this overload. The excess either gets washed off by rainfall or irrigation or else leaches from the soil into groundwater. An estimated 20 percent of the nitrogen that humans contribute to watersheds eventually ends up in lakes, rivers, oceans, and public reservoirs, opening a virtual Pandora’s box of problems.

Algae, like all living organisms, are limited by their food supply, and nitrogen is their staff of life. So when excess nitrogen is washed off into warm, sunlit waters, an algal bacchanalia ensues. Some species form what is known as a “red tide” for its lurid color, producing chemical toxins that kill fish and devastate commercial fisheries. When people eat shellfish tainted by a red tide, they can suffer everything from skin irritation to liver damage, paralysis, and even death. As Yeats put it, “the blood-dimmed tide is loosed.”

Algal blooms, even when nontoxic, block out sunlight and cut off photosynthesis for the plants living below. Then they die off and sink, depleting the water’s supply of oxygen through their decomposition and killing clams, crabs, and other bottom dwellers. In the Baltic Sea, nitrogen levels increased by a factor of four during the 20th century, causing massive increases in springtime algal blooms. Some ecologists believe this was the main cause of the collapse of the Baltic cod fishery in the early 1990s.

Every spring, the same process now creates a gigantic and growing “dead zone” one to 20 yards down in the Gulf of Mexico. The Mississippi and Atchafalaya rivers, which drain 41 percent of the continental United States, wash excess nitrates and phosphates from the farmlands of 31 states, as well as from factories, into the Gulf. The runoff has created a hypoxic, or deoxygenated, area along the coast of Louisiana toward Texas that has in some years grown as large as New Jersey. This area supports a rich fishery, and dire consequences similar to those in the Baltic Sea can be expected if nothing is done. So Haber’s gift of nitrogen was not entirely a boon in the area of food: It increased food production on land, but now it threatens our supply of food from the sea.

Four years ago the Environmental Protection Agency formed a task force of experts to address the dead-zone problem. Their final plan of action, submitted in January, calls for increased research, monitoring, education, and more planning. Above all, the plan proposes incentives for farmers to use less fertilizer. But the addiction will be hard to break. Unlike nuclear energy, nitrogen fertilizer is absolutely necessary to the survival of modern civilization. “No Nitrates!” and “Fertilizer Freeze Forever!” are not viable slogans. At the end of the 19th century there were around 1.5 billion people in the world, and they were already beginning to exhaust the food supply. Today, as the population surges past 6 billion, there is no way humanity could feed itself without nitrogen fertilizers. As Stanford University ecologist Peter Vitousek told us recently, “We can’t make food without mobilizing a lot of nitrogen, and we can’t mobilize a lot of nitrogen without spreading some around.”

Algal blooms are just one of the many disastrous side effects of runaway nitrogen. In Florida, for example, nitrogen (and phosphorus) runoff from dairies and farms has sabotaged the native inhabitants of the Everglades, which evolved in a low-nutrient environment. The influx of nutrient-loving algae has largely replaced the gray-green periphytic algae that once floated over much of the Everglades. The new hordes of blue-green algae deplete the oxygen and are a less favorable food supply. So exotic plants such as cattails, melaleuca, and Australian pine have invaded the Everglades. Just as shopping-mall and subdivision developers have paved over most habitable land to the east and south, these opportunists have covered the native marshes and wet prairies where birds once fed. Beneath the surface, the faster-accumulating remains of the new algae have almost completely obliterated the dissolved oxygen in the water. Few fish can survive.

Nitrogen also contaminates drinking water, making it especially dangerous for infants. It interferes with the necessary transformation of methemoglobin into hemoglobin, thus decreasing the blood’s ability to carry oxygen and causing methemoglobinemia, or blue baby syndrome. The EPA has named nitrates, along with bacteria, as the only contaminants that pose an immediate threat to health whenever base levels are exceeded, and increasingly they are being exceeded. According to a 1995 report by the U.S. Geological Survey, 9 percent of tested wells have nitrate concentrations exceeding the EPA limit; previous studies showed that only 2.4 percent of the wells were dangerous.

Mass-produced Nitrogen made modern warfare possible. What other explosions lie ahead?

Beefing up agriculture not only contaminates our water, it corrupts the air. As fertilizers build up in the soil, bacteria convert more and more of it into nitrous oxide (N2O). Nitrous oxide is best known as “laughing gas,” a common dental anesthetic, but it is also a powerful greenhouse gas, hundreds of times more effective than carbon dioxide, and a threat to the ozone layer. Like a Rube Goldberg contraption designed to create and foster life on Earth, our ecosphere can apparently withstand little tinkering. Bend one little pole the wrong way, and the whole interlocking mechanism goes out of whack.

Scientists around the world are working to reverse the effects of eutrophication, as the introduction of excessive nutrients is called. But while fuel-cell car engines and other advances loom in the near future, and chlorofluorocarbons have largely been replaced with safer chemicals, there is no such substitute for nitrogen. “An enormous number of people in the underdeveloped world still need to be better fed,” says Duke University biogeochemist William Schlesinger, “particularly in India and Africa. When they come online agriculturally, sometime in the next 50 years, at least twice as much nitrogen will be deployed on land each year.”

Improving the management of fertilizer is one good way to decrease runoff. If we can better understand exactly when crops need to absorb nitrogen, farmers can learn to apply fertilizer sparingly, at just the right time. “When application and uptake are coupled,” says Schlesinger, “it minimizes the amount of runoff.” In some watersheds like the Chesapeake Bay, farmers have reduced their nutrient runoff voluntarily. In other areas, farmers haven’t had a choice: When the Soviet Union and its economy collapsed, fertilizer was suddenly hard to come by near the Black Sea. As a result, the hypoxic zone in the Black Sea shrank appreciably.

Another, less drastic strategy for reducing the use of nitrogen is called “intercropping” and goes back to Roman times. By alternating rows of standard crops with rows of nitrogen-fixing crops, such as soybeans or alfalfa, farmers can let nature do their fertilizing for them. Intercropping could be a godsend to the developing world, where fertilizer is hard to come by. The difficulty is devising new plowing schemes, and farmers, like everyone else, are reluctant to abandon tried-and-true methods. But even successful farmers in the United States might be convinced. Aside from protecting the global environment— a somewhat intangible goal— intercropping could save them money on fertilizer. And farming areas are often most affected by groundwater contaminated by nitrates.

Other researchers are developing natural processes to clean up our mess. Just as some bacteria can draw nitrogen from the atmosphere and expel it as nitrates, others can consume nitrates and expel nitrogen molecules back into the air. Denitrifying bacteria are too scarce to clean up all nitrogen pollution, but they could be used much more extensively. For example, some farmers in Iowa and near the Chesapeake Bay drain their fields through adjacent wetlands, where denitrifying bacteria are common, so that excess nitrogen is consumed before it reaches streams, rivers, and bays.

Biologists willing to brave a slippery slope might want to go further, adding denitrifying bacteria to soil or water contaminated with nitrates. In the last few years several bacterial strains that might be useful have been identified. Why not genetically modify them to do exactly what we want? To anyone familiar with the ravages of invasive species worldwide, the danger is obvious.

Genetically modified microbes would have to be spread over large areas, making them hard to monitor. And in developing countries, where the need is greatest, there are few experts to do the monitoring.

The specter of genetically engineered bacteria spreading beyond the targeted regions, and mutating into new strains, brings to mind a picture of biogeochemists in the 22nd century looking back on the halcyon days when people still had the luxury of worrying about nitrogen. Fritz Haber couldn’t have imagined that he was altering Earth’s environmental balance when he thought to heat up uranium, hydrogen, and air at high pressure. If we’re not careful, our attempts to rectify that balance will only trigger another, even more destructive chain reaction.

Haber’s uranium was Oppenheimer’s uranium in more ways than one.

Posted in Fertilizer, Food, Natural Gas | Leave a comment

Out of time: 50 years to make a transition, 210 years at the current rate

If transportation is to be electrified, then electric generation and the electric grid must be doubled, or even tripled. So by Cobb’s calculation, that would push back the transition time to renewables 420 to 630 years.  Alice Friedemann.

By Kurt Cobb, October 1, 2012. Christian Science Monitor.

The clunky, lagging transition to renewable energy

History suggests that it can take up to 50 years to replace an existing energy infrastructure, and we don’t have that long.

No doubt you’ve heard people speak of an energy transition from a fossil fuel-based society to one based on renewable energy–energy which by its very nature cannot run out. Here’s the short answer to why we need do it fast: climate change and fossil fuel depletion. And, here’s the short answer to why we’re way behind: History suggests that it can take up to 50 years to replace an existing energy infrastructure, and we don’t have that long.

Perhaps the most important thing that people don’t realize about building a renewable energy infrastructure is that most of the energy for building it will have to come from fossil fuels.

Currently, 84 percent of all the energy consumed worldwide is produced using fossil fuels–oil, natural gas and coal. Fossil fuels are therefore providing the lion’s share of power to the factories that make solar cells, wind turbines, geothermal equipment, hydroelectric generators, wave energy converters, and underwater tidal energy turbines.

Right now we are producing at or close to the maximum amount of energy we’ve ever produced from fossil fuels. But the emerging plateau in world oil production, concerns about the sustainability of coal production, and questionable claims about natural gas supplies are warnings that fossil fuels may not remain plentiful long enough to underwrite an uneven and loitering transition to a renewable energy society.

This is what’s been dubbed the rate-of-conversion problem. In a nutshell, is our rate of conversion away from fossil fuels fast enough so as to avoid an unexpected drop in total energy available to society? Will we be far enough along in that conversion when fossil fuel supplies begin to decline so that we won’t be forced into an energy austerity that could undermine the stability of our society?

The answer can’t be known. But the numbers are not reassuring. Based on data from the U.S. Energy Information Administration, it would take more than 70 years to replace the world’s current electrical generating capacity with renewables including hydroelectric, wind, solar, tidal, wave, geothermal, biomass and waste at the rate of installation seen from 2005 through 2009, the last years for which such data is available. And, that’s if worldwide generating capacity–which has been expanding at a 4 percent clip per year–is instead held steady.

This also doesn’t take into account the amount of energy actually produced versus what is called nameplate capacity. Nameplate capacity is what a wind generator could generate if it operated at maximum capacity 100 percent of the time. But in practice, the turbines are only spinning when the wind blows and then not always at the maximum speed. This so-called capacity factor was just 27 percent for wind farms in the United Kingdom from 2007 to 2011. For solar photovoltaic the number was 8.3 percent. Even hydroelectric stations ran at only about 35 percent of capacity. This compares to about 42 percent for conventional coal, 61 percent for natural gas, and 60 percent for nuclear power stations (PDF). The contrast is starker using U.S. numbers: 72 percent for coal and 91 percent for nuclear using 2008 figures, though natural gas was only 11 percent, probably because these were primarily plants that only come on to meet peak demand and so don’t run very often.

What this means is that installing two to three times our current nameplate capacity in the form of renewables may be required to replace existing fossil-fueled plants. So, the transition period would actually turn out to be longer than what I’ve calculated, perhaps 140 to 210 years using 2005 to 2009 installation figures.

Of course, installations of such renewables as wind and solar are accelerating. So, that would tend to shorten this longer transition period–as would leaving existing nuclear power capacity intact. But would we be able to shorten the transition period enough to head off declines in total energy production and prevent additional serious damage to the climate?

Of course, some would say that we need to expand nuclear power generation rapidly to meet these challenges. Whether you support such an expansion or not, there are three key problems. First, building enough nuclear power stations to replace fossil fuel-fired plants would be the largest construction project ever undertaken and require the use of enormous amounts of fossil fuels. Making the necessary concrete alone would be a large new contributor to greenhouse gas emissions. That means that the initial phase of a nuclear transition would actually increase the rate of fossil fuel emissions. The savings on fuel and emissions wouldn’t come until much later.

Second, after the Fukushima disaster, there doesn’t seem to be much appetite for such a buildout. I’ll be very surprised if nuclear power generation even maintains its current level in the next 20 years as Japan and Germany abandon nuclear power. Third, the timeline for such a buildout would be measured in decades, partly because of the sheer logistics involved and partly because of the brake that regulatory approvals put on such projects. Even new, cheaper and easier-to-build designs may not help if they cannot achieve the necessary regulatory approvals promptly. The history of such approvals is not encouraging. The safest thing a nuclear regulatory agency can do is say no.

I haven’t even touched on replacing the fuels which power our transportation system and provide heat for our buildings and industrial processes. Transportation offers an extraordinary challenge since 80 percent of all transportation fuel worldwide is still derived from petroleum. In the United States the number is 93 percent. Despite billions of dollars spent and decades of research, we still have no good substitutes that scale to the size necessary to replace petroleum for transportation fuel.

Biofuels offer little hope. Already the ethanol bubble has burst. Biofuels–today mainly ethanol and biodiesel–compete with food. There is simply not a limitless supply of suitable farmland, and so there will be competition with the demand for food until we find substitutes for the industry’s main feedstocks, namely corn, sugar and soybeans.

Beyond this the problem of scale is simply unsolvable. To supply the entire U.S. car fleet–assuming it could run on ethanol–we’d have to plant 1.8 billion acres in corn for ethanol continuously. There are only about 440 million acres in the United States in cultivation now. And, it’s worth noting that current methods of corn cultivation require the copious use of herbicides and pesticides made from oil; tractors and other vehicles that run on oil to plow, harvest and spray the fields as well as transport the crop; and natural gas-derived nitrogen fertilizers to boost growth and replenish depleted soil. Fossil fuels are currently integral to growing corn, and I cannot see the wisdom of growing organic corn for anything but food.

As for heat for buildings, certainly we could insulate and seal our existing buildings better. And, this points the way to achieving an energy transition within the time we need to achieve it. Since it will probably be impossible to scale renewable energy fast enough to a level sufficient to produce the amount of energy we use today, the one absolute necessity to a successful energy transition is reducing consumption drastically. No politician dares to say anything remotely approaching this. And yet, it would be the cheapest, fastest way to address the twin crises of fossil fuel depletion and climate change.

Now, when I say reduce, I mean on the order of 80 percent over the next 20 to 30 years. For Americans this may seem impossible until they contemplate that the average European lives on half the energy of the average American. So often we hope for technological breakthroughs that will give us all the clean energy we desire. But we ought to focus equally, if not more, on using our prowess to find ways to reduce our energy consumption drastically. This is actually the much easier road. When we are made conscious of our energy use, we can change our behavior quickly to modify it without compromising the quality of our lives. As more homes and businesses are given the means to monitor their energy use, the people in them will change to lower their consumption and costs.

Already we know how to build so-called passive design structures which can lower energy use by 80%. And, we desperately need to figure out how to apply these techniques cheaply and economically to existing homes and businesses. In transportation we need to stop thinking that cars equal transportation and instead realize that cars provide the service of transportation which can be obtained in a number of ways, many of which use much less energy.
We may also need to speed the energy transition in electric power generation using so-called feed-in tariffs. These tariffs–which harness the ingenuity of countless small producers–have enabled Germany to expand solar, wind and other alternatives so that they generate 25 percent of its electricity today. Germany, not a particularly sunny place, is currently the world’s top generator of solar electricity.

Of course, per person energy consumption in poor countries is only a small fraction of that in rich countries. We cannot expect the world’s poor to reduce their energy use by 80 percent. Instead, we must help them to move quickly beyond fossil fuels to renewable energy.

By simultaneously reducing consumption and encouraging a rapid buildout of renewable energy, it is possible that we could mitigate the problem of declining fossil fuel supplies before it becomes so acute that it would cripple that very build out. And, we could address climate change at the same time. Certainly, there are difficult problems to be solved with renewable energy, storage being the key one. Most renewable energy comes in the form of electricity, and since there is often a mismatch between the time we produce that electricity and the time we need it, we will have to master storage.

But we will need a lot less storage if we focus on reducing consumption. This is the one strategy which will allow us to overcome the rate-of-conversion problem and achieve an energy transition in far less time than we have in the past.

Posted in Alternative Energy, Electric Grid, Peak Oil | Tagged , , , | Leave a comment

Why You Should Love Trucks: If trucks stop, America stops.

Why You Should Love Trucks: If trucks stop, America stops.

by Alice Friedemann, September 27, 2014


Before the age of fossil fuels, getting food, water, and shelter was simple. Nine out of ten people were self-sufficient farmers.

But now there are long, 24/7 just-in-time supply chains that depend on trucks and other modes of transportation between us and what we need to survive.

By weight, trucks carry 70% of all freight an average of 206 miles.

Five million medium and heavy-duty trucks travel 329 billion miles to deliver all these goods.

Over 80% of communities in the United States depend completely on trucks for all their goods (ATA).

Trucks can substitute for most other kinds of transportation, but the reverse isn’t true. For example, there are only 140,000 miles of freight rail tracks, but over 4 million miles of roads.

Nearly all freight is carried by a truck at some point, since very few factories, warehouses, and businesses have direct rail or ship connections.

A container arriving by ship and then traveling by rail will still get on a truck at least three times:

  1. When it’s grabbed by a reach-stacker truck in the ship yard and loaded onto a train
  2. Unloaded by a reach-stacker truck at the train’s destination and
  3. Put onto a truck for delivery to a regional distribution center or store
  4. If the container is 40 feet or more and bound for a dense urban area, the contents are often transloaded to two smaller trucks for final delivery
truck-reachstacker-ctr-xferReach-stacker truck getting a container to load onto a truck or train

Most businesses are very dependent on trucks:

  • Trucks are a key part of the 24/7 just-in-time delivery system. Large grocery stores receive 10-15 truck shipments a day, assembly lines depend on regular deliveries of a wide range of parts from many suppliers within narrow time slots.  Manufacturers have little packaging material on hand because it’s bulky and low value.
  • Tax incentives and efficiency have driven businesses to keep as little inventory as possible and instead rely on frequent deliveries by trucks

Trucks fulfill our basic needs

Food.  Trucks carry 83% of all food.  Most of our food calories are grown in the interior (meat, grain, dairy), yet two-thirds of Americans live within a hundred miles of the coasts.  In the past such an enormous distance between food and population would have led to famine, but trucks and trains have (so far) prevented that.

Water. Trucks deliver water purification chemicals to water treatment plants every week or two.

Energy.  Trucks deliver fuel to service stations every 2.4 days on average. Trucks also deliver fuel for trains, ships, and airplanes.

Health: Trucks keep pharmacies and hospitals stocked

Shelter: Trucks haul 92% of wood products and deliver materials to construction sites.  Cement must arrive within 1-2 hours.

Electricity. 39% of electricity is generated by coal, which is delivered by train (71%) and truck (14%).

The National Academy of Sciences (NAS) looked at twelve different urban/suburban supply chains: pharmaceuticals, biotechnology, restaurants, urban wholesale food, big box retail, supermarkets, waste and recyclables, soft drinks, apparel, retail drug stores, and hospitals.   Trucks always make the final delivery, and usually some or the previous legs as well (NAS). Here are some examples from this study.  All those blue lines are trucks.

supply chain modesupply chain supermarketssupply chain wastesupply chain cement

If Trucks Stopped Running

I found three articles about what would happen if trucks stopped running.  All of them reached similar results, which I’ve combined below (Holcomb, McKinnon, SARHC). Of course, this is just a partial list of what would occur.

Day 1 without trucks

  • Manufacturers and assembly lines that use just-in-time delivery will shut down when parts run out or storage for finished products fills up.
  • Hospitals will run out of supplies like syringes and catheters within hours.
  • Milk and fresh bread will run out.

Day 2 without trucks

  • Food shortages will escalate, especially in the face of hoarding and consumer panic. Supplies of essentials and perishable foods will disappear
  • Restaurants and fast food outlets close
  • ATMs will run out of cash
  • Construction stops
  • Pharmacies close
  • Americans generate 685,000 tons of trash per day. Garbage will start piling up in urban and suburban areas creating a health hazard.

Day 3 without trucks

  • Most service stations will run out of fuel
  • Widespread lay-offs in the manufacturing sector
  • Waste water sludge becomes a problem as tanks at treatment plants are now full
  • Work on infrastructure stops as repairs can’t be undertaken
  • Public transport, fire, police, ambulances, telecommunications, utilities, mail, and other essential services stop

Day 4 without trucks

  • The repercussions start to reverberate globally, as 48,000 imported containers per day can’t be unloaded off of ships. Exports stop too.
  • All fuel supplies are depleted from service stations. Many people can’t get to work
  • With no fuel, airplanes and railroads shut down.
  • Garbage is piling up and has become a sanitary problem
  • Britain is out of beer

Day 5 without truck transport

  • Drinking water is depleted. The delay of weekly deliveries of chemicals has meant that water treatment plants can no longer guarantee that water is fit to drink.
  • Industrial production stops, a large proportion of the labor force is laid-off or unable to get to work, travel and recreation stop
  • Healthcare is confined to emergency services
  • Utilities have localized disruption of gas and electricity, and due to lack of fuel can’t pump water and gas, repair broken water and gas networks, etc
  • Livestock begin to suffer from lack of feed deliveries, wastes accumulate, ranchers can’t transport animals to slaughterhouses,  meat production stops
  • The Swedish Alcohol Retail Monopoly is out of alcohol

Within four weeks:

  • The nation will exhaust its clean water supply and water will be safe for drinking only after boiling.
  • If this happened at harvest time, many crops will rot in the fields
  • The Department of Defense supply chain will break down, crippling the military “in ways no adversary has been able to achieve”.
  • Global financial collapse (my addition).  A halt of international trade would bring the financial system down, probably sooner than this.

American Truckers react to “When Trucks Stopped” (CDLLife)

Many truck drivers thought they ought to stop driving to make people respect and care about them more:

  • The country would stop! At times I think that is what needs to happen! 32 years of being out here, looking out a windshield and watching life go by! Companies and the public not treating us, the back bone of this country, with any respect! Companies just think we are machines and we have no life outside this truck! The rules and regulations are getting stupid and taking money away from the driver and his or hers family! It also puts us in the truck longer! But, if the gas and diesel haulers just shut down for 72 hours, watch what happens!
  • We tried that for YEARS. The Big Companies won’t allow there drivers to shut down. They are to money hungry. The OWNER OPERATORS try but they can’t do it by themselves. So it doesn’t get done. Great idea but hasn’t worked in the past.
  • Like James Cameron said the owned ops would have to block fuel islands there are so many foreign fu@ks that will not stop nor care about are problems and these big company’s have so many of us by the balls
  • you know just as well as I do that wont happen unless every driver out there will participate. were just like the rest of the human race. only a hand full care to know the truth. the rest dont care. just like our presedent.
  • Let’s stop talking about it and just do it…. We run this country, not some bullshit government
  • Teach the government that trucks are needed for life on earth
  • Every other means of transportation is subsidized my the government except us!!!!! That tells me, that the government does not think of us very upstanding. It shows me that they don’t care for us. Trucking is the only industry that is governed on how many hours you can work, you are told when to sleep, when to get up, and basically told when you can see your family. We’re like Ronnie Milsaps’ song states, Prisoners of the Highway!!!!!

Truckers comment on what would happen:

  • Stores would be empty inside of a week for one. Rioting and lawlessness would set in soon after.
  • The life as we know it will end, there’s only one thing that’s not shipped by truck and that’s the air we breathe….
  • Everybody dies
  • World War 3
  • the world would probably end
  • America will fall apart!!!
  • There would be alot of cold hungry naked people out there
  • Everybody dies


There are many reasons trucks could stop running, but my concern is the inevitable time when oil production has fallen so low it impacts the ability of trucks to do the essential work of society.

The United States government (DOE, EIA, EERE, National Laboratories, and state governments) and private businesses are well aware of this problem and have teamed up to try to make trucks that get better mileage, or can run on alternative fuels like biodiesel, batteries, compressed natural gas, or other fuels.

The next few posts will focus on how we can keep trucks running, because without trucks, America stops.


ATA. American Trucking Association. About Trucks Bring It. November 30, 2013. If Trucks stopped…

Holcomb, Richard D. July 14, 2006. When Trucks Stop, America Stops. American Trucking Association.

McKinnon. November 2004. Life without Lorries: The impact of a temporary disruption of road freight transport in the UK. Commercial motor magazine.

NAS National Academy of Sciences. 2012. NCFRP Report 14: Guidebook for Understanding Urban Goods Movement.

SARHC. A Week without Truck Transport. Four Regions in Sweden 2009. Swedish Association of Road Haulage Companies.




Posted in Agriculture, Supply Chains, Transportation, Trucks | 3 Comments

Gas to Liquids (GTL)

Not going to happen anytime soon:

February 19, 2014. United States Energy Information Administration

Gas-to-liquids plants face challenges in the U.S. market

Gas-to-liquids (GTL) is a process that converts natural gas to liquid fuels such as gasoline, jet fuel, and diesel. GTL can also make waxes.

The most common technique used at GTL facilities is Fischer-Tropsch (F-T) synthesis. Although F-T synthesis has been around for nearly a century, it has gained recent interest because of the growing spread between the value of petroleum products and the cost of natural gas.

The first step in the F-T GTL process is converting the natural gas, which is mostly methane, to a mixture of hydrogen, carbon dioxide, and carbon monoxide. This mixture is called syngas. The syngas is cleaned to remove sulfur, water, and carbon dioxide, in order to prevent catalyst contamination. The F-T reaction combines hydrogen with carbon monoxide to form different liquid hydrocarbons. These liquid products are then further processed using different refining technologies into liquid fuels.

Diagram of GTL process, as explained in the article text

Source: U.S. Energy Information Administration

The F-T reaction typically happens at high pressure (40 atmospheres) and temperature (500o-840oF) in the presence of an iron catalyst. The cost of building a reaction vessel to produce the required volume of fuel or products and to withstand these temperatures and pressures can be considerable. Several companies are pursuing an alternative method that uses a different reactor design (called a micro-channel reactor) and proprietary catalysts that allow GTL production at much smaller scales.

There are currently five GTL plants operating globally, with capacities ranging from 2,700 barrels per day (bbl/d) to 140,000 bbl/d. Shell operates two in Malaysia and one in Qatar, Sasol operates one in South Africa, and the fifth is a joint venture between Sasol and Chevron in Qatar. One plant in Nigeria is currently under construction.

Three plants in the United States—in Lake Charles, Louisiana; Karns City, Pennsylvania; and Ashtabula, Ohio—are proposed. Of these, only the Lake Charles facility is a large-scale GTL plant.

In December 2013, Shell cancelled plans to build a large-scale GTL facility in Louisiana because of high estimated capital costs and market uncertainty regarding natural gas and petroleum product prices.

The Annual Energy Outlook 2014 (AEO2014) does not include any large-scale GTL facilities in the United States through 2040.

Other uses for available natural gas in industry, electric power generation, and exports of pipeline and liquefied natural gas are more economically attractive than GTL.

To improve the long-term profitability of GTL plants, developers have reconfigured their designs to include the production of waxes and lubricating products, which are another primary product of the F-T process. Because of the smaller size of the chemical market, smaller-scale GTL plants similar to those proposed in the Midwest are economically viable. U.S. imports of waxes similar to those produced out of the F-T process have experienced steady growth over the past decade because of increased demand in the chemicals market. F-T waxes are used in industries producing candles, paints and coatings, resins, plastic, synthetic rubber, tires, and other products.

Using projected natural gas and product prices in the AEO2014 Reference case and assuming a GTL plant can produce 2,800 barrels per day of products, a GTL plant is projected to be profitable only when it is configured to maximize wax production. As such, most GTL developers are looking to configure their plants to maximize wax production for the chemicals market instead of production of liquid fuels with minimum or no wax.

Graph of GTL profits, as explained in the article text

Source: U.S. Energy Information Administration, Annual Energy Outlook 2014

Posted in GTL Gas-To-Liquids | Leave a comment

Can Railroad locomotives run on LNG (Liquified Natural Gas)

Building new LNG locomotives would be really stupid given that fracked natural gas production in America will peak roughly 2015-2018 and decline at an alarming rate, given the 60% per year decline rate of fracked natural gas wells.  There have been many articles written about why shale oil gas is a flash in the pan. See my post Shale Oil and Gas Will Not Save Us for details.  And we don’t have the infrastructure to import LNG if we did make the mistake of making railroads dependent on natural gas.

Knock on effects include coal power plants unable to generate electricity, since trains deliver 67% of coal, and refineries impacted by trains unable to deliver 759,000 barrels per day (2014), 8% of USA oil production.

Challenges for liquefied natural gas as a freight rail fuel (Chase)

While simple economic calculations involving the comparison of fuel cost savings to additional upfront cost are relatively straightforward, other factors, including operational, financial, regulatory, and mechanical challenges, also affect fuel choices by railroads. One of the most challenging factors raised by the switch to LNG locomotives by Class 1 railroads is the effect on operations. Switching from diesel fuel to LNG would require a new delivery infrastructure for locomotive fuel. Natural gas would need to be delivered to fuel depots, either by truck in smaller quantities, as LNG [4],or perhaps by pipeline. Larger quantities of natural gas would require liquefaction before delivery to tender cars for use in locomotives. Building the new infrastructure would require a large financial investment in addition to the large investments made in locomotives and tender cars.

The building of LNG refueling infrastructure could also complicate the inter-operability of the rail network, depending on how quickly modifications could be made to accommodate refueling at multiple points around the nation. Impeding the ability of the rail network system to move goods because of a lack of fuel availability could drive up costs and lead to reductions in network flexibility and operational efficiency [5]. In addition, operations could be further affected by fuel switching because of the cost of training staff at refueling depots and in maintenance shops, updating maintenance facilities to handle LNG locomotives and tenders, and managing more extensive logistics [6]. Further, LNG locomotives and tender cars could require more maintenance than their diesel counterparts. All of these operational changes would create a duplicative infrastructure [7], because many diesel-fueled locomotives still would be in service at least for some significant period, and compression-ignited LNG locomotives still require at least some diesel fuel for combustion ignition.

Replacing the current stock of diesel locomotives with LNG locomotives and tender cars would represent a significant financial investment by Class 1 railroads. In 2012, there were 25,174 locomotives in the service of Class 1 railroads, the vast majority of which were line-haul locomotives [8]. A new diesel line-haul locomotive costs about $2 million [9], and rebuilt locomotives cost about half that amount. With a new LNG locomotive and tender costing about $1 million more than a diesel counterpart, the cost to replace the entire diesel locomotive stock with LNG locomotives and tenders would be tens of billions of dollars, not including additional infrastructure, training, logistics, and a potential increase in maintenance costs. Moreover, much of the cost of the transition, such as purchases of locomotives and tender cars, potentially would occur over a much shorter time period than a fuel payback period.

The financing requirement of large capital expenditures complicates the rather straightforward calculation of locomotive fuel economics. The amount of capital available to Class 1 railroads, either on hand or raised in capital markets, is an important factor in determining whether, or to what extent, railroads can take advantage of fuel cost savings over time. The decision to switch from diesel fuel to LNG is also influenced by the facts that railroads are a highly capital-intensive industry [10] with complete responsibility for maintaining the physical rail network, that they face many competing needs for financial investment, and that they must ensure adequate return on investment for their shareholders.

On the regulatory side, LNG rail cargos currently are not permitted without a waiver from the Federal Railroad Administration (FRA) under Federal Emergency Management Agency (FEMA) rules. The development of standard LNG tenders and regulations is underway, with issues related to safety, crashworthiness, and environmental impact, including methane leakage, under consideration [11].

Finally, LNG locomotives currently are undergoing extensive testing and demonstration to determine their fuel consumption, emissions, operational performance, and range under real-world conditions. Locomotives and tenders will be evaluated to ensure mechanical performance of such components as connections between tender and locomotive. Several Class 1 railroads are planning to start LNG locomotive demonstration projects to provide better understanding of the obstacles to an LNG fuel switch.

Chase, N. April 14, 2014. Potential of liquefied natural gas use as a railroad fuel. United States Energy Information Administration.

Posted in LNG Liquified Natural Gas, Railroads | Leave a comment

Irrigation uses a lot of electricity, requires expensive grid in remote areas

“Irrigation load from farm irrigation systems can be costly to serve, because of the high cost of connecting these dispersed systems to the electric grid and the high cost of having enough capacity available to meet seasonal irrigation load.”

Alice Friedemann comment: After natural gas production peaks sometime between 2015-2018, the electric grid may not be up 24 x 7. On top of that, there will be longer and more frequent droughts and heat waves, leading to less hydro-power and a greater need for electrically-pumped irrigation water, and this is likely result in very high food prices and less irrigated food production.

United States Department of Agriculture irrigation statistics:

  • Irrigated agriculture accounts for the largest share of the Nation’s consumptive water use.
  • Roughly 57 million acres–or 7.5 percent of all U.S. cropland and pastureland–were irrigated in 2007
  • In 2007, irrigated farms accounted for 55 percent of the total value of crop sales while also supporting the livestock and poultry sectors through irrigated production of animal forage and feed crops.
  • The U.S. Geological Survey, which monitors water use by economic sector, estimates that irrigated agriculture accounted for 37% of the Nation’s freshwater withdrawals in 2005.
  • Population and economic growth, Native American water-right claims, and water quality/environmental priorities are increasing the demand for water resources. Expansion of the U.S. energy sector is also expected to increase regional demands for water. In much of the West where irrigation is concentrated, climate change could shrink water supplies as a result of warming temperatures, shifting precipitation patterns, and reduced snowpack, while also increasing water demand.

May 12, 2014

Many industrial electricity customers are farmers

graph of number of industrial electric customers, top-10 states, as explained in the article text

Source: U.S. Energy Information Administration, Electric Power Annual

Republished May 12, 4:00 p.m. to clarify maps and content.

Farmers make up a significant share of industrial electricity customers in certain states. This is because of demand from farm irrigation systems, which are categorized by electric utilities as industrial load. For example, Nebraska is largely rural and agricultural, but it has the third-highest count of industrial electricity customers in the United States. The same factor drives up the number of industrial electricity customers in Idaho and Kansas, which are also among the top 10 states in number of industrial electricity customers. States with a large agriculture industry also tend to have among the lowest industrial sales of electricity per industrial customer.

Irrigation load from farm irrigation systems can be costly to serve, because of the high cost of connecting these dispersed systems to the electric grid and the high cost of having enough capacity available to meet seasonal irrigation load. Dawson Public Power District, a rural electric cooperative in an agriculture-heavy region of Nebraska, accounted for less than 3% of statewide industrial electricity sales in 2012 but had one of the highest average prices for industrial power. In general, the highest industrial electricity prices in Nebraska tend to be located in the rural southern and western portions of the state.

The two largest utilities (Omaha Public Power District and Nebraska Public Power District) that distribute electricity for about 40% of all the megawatthours sold to industrial customers in the state in 2012.

map of U.S. industrial electric customer counts, as described in the article text

Source: U.S. Energy Information Administration, Electric Power Annual

A number of industrial electricity customers are concentrated in the Great Plains states and other agricultural-heavy states like Idaho and California.

Many agricultural-heavy electric utilities use demand-response programs to manage the costs of connecting a large number of small users to the grid. Nebraska’s Dawson Public Power offers lower rates for agricultural customers who allow the utility to control the electric usage of these systems when demand for electricity is high, a form of demand response. This allows the grid operator to adjust the load shape in a given day and reduce the need to bring on more expensive sources of electricity generation.

Posted in Electric Grid, Food | Leave a comment

Two-thirds of coal to power sector delivered by railroads

June 11, 2014

Railroad deliveries continue to provide the majority of coal shipments to the power sector

graph of coal shipments to the electric power sector by transit mode and year, as explained in the article text

Source: U.S. Energy Information Administration, Form EIA-923, Power Plant Operations Report
Note: Sum of components may not equal 100% because of independent rounding. Other includes Pipeline, Other Waterway, Great Lakes Barge, Tidewater Pier, and Coastal Ports. Data for 2013 are preliminary.
Note: Intermodal transit uses multiple modes of delivery. Intermodal rail includes some movement over railways, while intermodal nonrail signifies multiple modes that do not include railway.

In 2013, electric power generators consumed 858 million tons of coal, accounting for 93% of all coal consumed in the United States and 39% of electric power generation. Two-thirds of the coal (67%) was shipped either completely or in part by rail. The balance was moved by river barge (especially over the Mississippi and Ohio rivers and their tributaries), truck, and—for power plants located at the coal mine—by conveyor.

The coal transportation network is most densely concentrated in the eastern portion of the United States. This area contains many relatively small coal mines, most of the country’s coal-fired power plants, and also rail infrastructure and suitable waterways. In the western United States, coal mines are often large, and a small number of routes handle large amounts of coal.

The primary mode by which a power plant receives its coal is largely determined by its location and access to the rail system. River barge is the most cost-effective method of transporting large quantities of coal over long distances, but the option is limited to plants located on a suitable river. Transporting coal by rail is more expensive, but two related facts result in its dominant market share of transportation: first, the United States is covered by an extensive railway network; and second, coal is produced in a relatively few parts of the country—predominantly in the Powder River Basin (Wyoming and Montana), the Illinois Basin, and Central and Northern Appalachia—while it is consumed by power plants in 46 of the 48 contiguous states.

By the numbers—how many trains and how much coal?

To better comprehend the amount of coal that a power plant consumes, consider that the largest coal-fired plants in the country receive 1 or 2 unit trains of coal each day. Each train has approximately 115 cars, and each car carries an average of 116 tons of coal. Some plants receive more than 26,000 tons of coal in a single day.

After rail and river barge, the third most common method of receiving coal is by truck (10%). This method, however, is typically employed only by plants that are located relatively close to a coal mine because of the higher cost on a per-ton-mile basis. Those plants that are located directly at or very near a mine can also have their coal delivered by conveyor, but, taken together, truck, barge, and conveyor movements make up less than 30% of the coal shipments in the country.

The prominence of rail has not changed in recent years, although slight fluctuations occur as a result of changes in plant operators’ coal supply requirements. These changes are driven by a combination of factors, including recent and expected retirements of coal-fired generators, the installation of sulfur dioxide scrubbers at an increasing number of plants that widens the range of coals a plant may burn, changes in regional coal prices, and competition with natural gas and renewable energy. Although coal consumption in the electric power sector decreased by 18% from 2008 to 2013, and the number of coal-fired generators dropped from 1,445 to 1,285 units during that same period, the share of shipments made either exclusively by rail or with rail as the primary mode has remained effectively unchanged.

Between 2008 and 2013, the share of coal shipments made by river barge increased from 7% to 12%. In contrast, truck shipments fell from 12% to 10%, and shipments made by other modes (i.e., nonriver barge waterways, pipeline, tidewater piers, and coastal ports), fell from 7% to 1%. These changes occurred because many of the plants that received their coal by one of the other modes in 2008 either retired or shifted to another mode.

Posted in Coal, Railroads, Trucks | Leave a comment

Fuel economy improvements show diminishing returns in fuel savings

This means it’s unlikely we’ll turn over the vehicle fleet fast enough to make a difference in fuel consumption.  Which wouldn’t have happened anyhow due to Jevon’s paradox.

July 11, 2014

Fuel economy improvements show diminishing returns in fuel savings

graph of annual fuel savings and fuel cost savings by miles per gallon, as explained in the article text

Source: U.S. Energy Information Administration, Annual Energy Outlook 2014
Note: Calculations in graphic assume a fuel price of $3.50 per gallon and annual travel of 12,000 miles per vehicle.

Fuel costs, which depend on vehicle fuel economy, miles driven, and fuel price, are an important factor in vehicle purchasing decisions. However, fuel economy improvement exhibits diminishing returns in fuel savings. For example, switching from a 10-mile-per-gallon (mpg) vehicle to a 15-mpg vehicle saves more fuel and results in greater fuel cost savings than switching from a 25-mpg vehicle to a 75-mpg vehicle. The fuel and cost savings of improving fuel economy from 12 mpg to 15 mpg are the same as increasing from 30 mpg to 60 mpg.

Much of the reduction in fuel consumption and fuel cost comes from incremental fuel economy improvement at the relatively low fuel economy levels. For a consumer who drives 12,000 miles per year and pays $3.50 per gallon for gasoline, increasing fuel economy from 10 mpg to 11 mpg saves $382 in annual fuel cost and from 30 mpg from 31 mpg saves $45; raising fuel economy from 40 to 41 mpg saves just $26 and from 60 to 61 saves $11.

Posted in Automobiles | Leave a comment

EIA definition of Proved Reserves and Resources

July 17, 2014

Oil and natural gas resource categories reflect varying degrees of certainty

graph of oil and natural gas resource categories, as explained in the article text

Source: U.S. Energy Information Administration
Note: Resource categories are not drawn to scale relative to the actual size of each resource category. The graphic shown above is applicable only to oil and natural gas resources.

Crude oil and natural gas resources are the estimated oil and natural gas volumes that might be produced at some time in the future. The volumes of oil and natural gas that ultimately will be produced cannot be known ahead of time. Resource estimates change as extraction technologies improve, as markets evolve, and as oil and natural gas are produced. Consequently, the oil and gas industry, researchers, and government agencies spend considerable time and effort defining and quantifying oil and natural gas resources.

For many purposes, oil and natural gas resources are usefully classified into four categories:

  • Remaining oil and gas in-place (original oil and gas in-place minus cumulative production at a specific date)
  • Technically recoverable resources
  • Economically recoverable resources
  • Proved reserves

The oil and natural gas volumes reported for each resource category are estimates based on a combination of facts and assumptions regarding the geophysical characteristics of the rocks, the fluids trapped within those rocks, the capability of extraction technologies, and the prices received and costs paid to produce oil and natural gas. The uncertainty in estimated volumes declines across the resource categories (see figure above) based on the relative mix of facts and assumptions used to create these resource estimates. Oil and gas in-place estimates are based on fewer facts and more assumptions, while proved reserves are based mostly on facts and fewer assumptions.

Remaining oil and natural gas in-place (original oil and gas in-place minus cumulative production). The volume of oil and natural gas within a formation before the start of production is the original oil and gas in-place. As oil and natural gas are produced, the volumes that remain trapped within the rocks are the remaining oil and gas in-place, which has the largest volume and is the most uncertain of the four resource caetgories.

Technically recoverable resources. The next largest volume resource category is technically recoverable resources, which includes all the oil and gas that can be produced based on current technology, industry practice, and geologic knowledge. As technology develops, as industry practices improve, and as the understanding of the geology increases, the estimated volumes of technically recoverable resources also expand.

The geophysical characteristics of the rock (e.g., resistance to fluid flow) and the physical properties of the hydrocarbons (e.g., viscosity) prevent oil and gas extraction technology from producing 100% of the original oil and gas in-place.

Economically recoverable resources. The portion of technically recoverable resources that can be profitably produced is called economically recoverable oil and gas resources. The volume of economically recoverable resources is determined by both oil and natural gas prices and by the capital and operating costs that would be incurred during production. As oil and gas prices increase or decrease, the volume of the economically recoverable resources increases or decreases, respectively. Similarly, increasing or decreasing capital and operating costs result in econmically recoverable resource volumes shrinking or growing.

U.S. government agencies, including EIA, report estimates of technically recoverable resources (rather than economically recoverable resources) because any particular estimate of economically recoverable resources is tied to a specific set of prices and costs. This makes it difficult to compare estimates made by other parties using different price and cost assumptions. Also, because prices and costs can change over relatively short periods, an estimate of economically recoverable resources that is based on the prevailing prices and costs at a particular time can quickly become obsolete.

Proved reserves. The most certain oil and gas resource category, but with the smallest volume, is proved oil and gas reserves. Proved reserves are volumes of oil and natural gas that geologic and engineering data demonstrate with reasonable certainty to be recoverable in future years from known reservoirs under existing economic and operating conditions. Proved reserves generally increase when new production wells are drilled and decrease when existing wells are produced. Like economically recoverable resources, proved reserves shrink or grow as prices and costs change. The U.S. Securities and Exchange Commission regulates the reporting of company financial assets, including those proved oil and gas reserve assets reported by public oil and gas companies.

Each year EIA updates its report of proved U.S. oil and natural gas reserves and its estimates of unproved technically recoverable resources for shale gas, tight gas, and tight oil resources. These reserve and resource estimates are used in developing EIA’s Annual Energy Outlook projections for oil and natural gas production.

  • Unproved technically recoverable oil and gas resource estimates are reported in EIA’s Assumptions report of the Annual Energy Outlook. Unproved technically recoverable oil and gas resources equal total technically recoverable resources minus the proved oil and gas reserves.

Over time, oil and natural gas resource volumes are reclassified, going from one resource category into another category, as production technology develops and markets evolve.

Additional information regarding oil and natural gas resource categorization is available from the Society of Petroleum Engineers and the United Nations.

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Become a Bison rancher

Far more buffalo can be grazed per acre than cattle. It’s likely wild bison will return to the Great Plains in the future.   Already there are fewer people in areas where the Ogalla aquifer has been depleted than when Native Americans roamed the tall grass prairie.

Lott’s book “American Bison” is hardly a bison ranching manual — in fact the book might scare potential bison ranchers away.

Below are some of my favorite paragraphs from this book (which I found in its entirety online). If you’re intrigued, you can buy the book at amazon for only four dollars (on September 21, 2014).

Lott, Dale F. 2002. American Bison: A Natural History. University of California Press.

It’s hard to imagine-as you fly above mile after mile of corn, soybeans, and cattle feedlots or drive between them-but before East Africa became safari land, rich adventurers went on safari on the Great Plains. Buffalo Bill got his start in show business by laying on a safari for the Czarevitch of Russia-the Grand Duke Alexis. The Great Plains was a good choice. This vast, little-disturbed natural community covered a third of the United States-creating wonder, inviting adventure. Part of the appeal was the exotic indigenous people, but the main attraction was a sea of grass inhabited by an assemblage of animals mostly unknown elsewhere, and dominated by enormous herds of buffalo.


In late July and early August, plumes of dust, rising with earth-warmed air from the brown grass and rolling rangeland, ascend into that bowl. The dust makers, a herd of bison on the National Bison Range, are going about their business-breeding;


Most of the dust comes from wallows, shallow pits where the bison have torn away the sod with their horns and where the subsoil, dried by the sun and stirred by hooves and horns, turns to a flourlike dust. Some of the plumes start when threatening bulls paw and roll in these wallows; but most occur when fighting bulls plow the soil with their hooves, or when they slam their heads together and the shock explodes dust from their bodies. Now an old bull bellows. His back arches, his belly lifts, his neck extends, and a sound that seems equal parts lion’s roar and thunderclap booms across the grass. An eighteen-inch scar runs up his ribs. His horn tips, shattered in other battles, are blunted and worn. Fifty yards away his opponent, a six-year-old bull in his prime, bellows back, glances at the cow he is tending, then urinates into the dust of a wallow and rolls in it, slamming his 2,000 pounds sideways into the dust. It spurts from beneath him, filling the air around him like the burst of smoke a stage magician vanishes into. The prime bull emerges from this cloud, headed toward the old bull in a menacing walk. His forefeet stamp with each step, making the hair pantaloons on his legs dance and exploding little puffs of dust from his coat. As each front foot stamps, the bull snorts. His tail stands up like a living question mark. It’s an impressive display, and from where I sit, in an ancient jeep, an intimidating one. But the old bull is not intimidated. He too has wallowed and now advances, matching stamp with stamp, snort with snort. As they grow closer their bellows intensify; they seem to signify pure fury. Most such challenges seem to be elaborate tests of the opponent’s determination and end without a fight. Most fights involve a cautious locking of horns or hooking uppercuts or shoving head to head, ended when one animal signals submission and the winner lets him go. But this is not a test of determination and it’s a different kind of fight-one of those in which the bulls hurl themselves at each other, elongating their bulky bodies into animated battering rams as they launch themselves for the first blow. Their heads come together with a terrific shock. It ripples through their bodies in a visible wave. I once saw a bull somersaulted backward by such a charge: 2,000 pounds of bull flipped upside down like a lawn chair in a gust of wind. Both these bulls hold position after the first shock and dig in for a serious fight. They slam their heads together again. Clumps of hair the size of a fist are caught between their short, heavy, curved horns, then sheared off and tossed into the air. The animals circle, each trying to reach the other’s flank with a hooking horn. Both pivot around their forefeet with the speed of featherweight boxers, and each parries the other’s seeking horns with his own while their powerful necks absorb some of the force of the impact. Their hair absorbs some too. By the time a bull is six years old, a mat of hair several inches thick extends from the top of his head down across his forehead, thinning gradually until it stops just above his muzzle. His eyes peer from shallow wells, his ears flick out from deep recesses, and the space between his horns is completely filled with this luxuriant growth. Beneath this natural shock absorber, a thick layer of tough hide covers a rock-solid skull. Now the bulls lock horns and push hard, their hooves plowing soil as each tries to drive his opponent back. The old bull is pushed back and a little sideways, dust spurting from beneath his skidding feet. Suddenly a foot catches on a rock and he trips and falls onto his side. It is rare for a helpless bull to be attacked by the winner, but this time it happens. The younger bull strikes down and forward with his horns, slamming them into the old bull’s flank and hooking right and left. The curves of his horns make most of the contact and deliver bruising, possibly rib-breaking, but not fatal blows. Then the tip of one horn plunges through skin and muscles and into his opponent’s abdomen. Only one horn penetrates, and it penetrates only once, but the wound will be mortal.


While physical prowess is an essential tool in managing a relationship between two males, it can’t be the only tool, and in fact it’s one of the least-often used. Much more frequently they use communication


A territorial animal can predict attack pretty successfully by knowing territorial boundaries. The territory owner usually challenges all competitors within a given space and keeps up the pressure with threats and attacks until they leave. But bull bison aren’t territorial. They are roamers, drifting singly or in small, temporary groups. Because they cannot use their location in space to predict whether or not another animal will attack them, they read the animals around them, detecting and responding to behavior that consistently precedes an attack.


A bull doesn’t just walk toward his opponent: he stamps with each step, setting his foreleg pantaloons dancing, and grunting with each stamp. If forewarned is forearmed, why not attack first and give indication later? The reason, of course, is that it may not be necessary to attack at all.


Fighting is an occasionally necessary grand spectacle, but the real biological drama lies in the complex, drawn-out, and frequently subtle ways in which most conflicts are settled by communication. Bulls do most of their communicating during the breeding season-the only time during the year that mature bulls and cows are together for any length of time. The bulls have been alone or in small, temporary groups. Now they join the cows, which have been living in larger groups with the calves and young bulls. The bulls seek out cows about to breed and stay with them (they “tend” them), keeping other bulls away by threatening and fighting. But threatening and fighting are also common between bulls that are not defending cows. Since receptive cows are the only scarce resource in the bull’s economy, this seems surprising at first: one wonders what the nontending bulls are fighting about. But a rival dominated now will probably give way later without a contest, saving a tending bull time and energy when he has none to spare. Not that the bull works it all out in this fashion. He simply has a powerful urge to dominate other bulls, and following this impulse works to his advantage. The drive to dominate is so powerful that it occasionally interferes with his real business and its ultimate function-bulls will sometimes leave a receptive cow to threaten a distant bull.


On a still day a bull’s bellow carries for miles. It’s a sort of roaring rumble, and if you can’t see the bull or don’t recognize the sound you may guess it’s a thunderstorm. If the competition presses, the bellowing becomes louder, and a quality that is hard to define but somehow easy to recognize-a quality of fury-begins to grow in it. Often one or both bulls will interrupt their bellowing to paw the ground or wallow.


If the challenge does not end at the wallowing or bellowing stage, the bulls draw closer to each other and begin to posture. There seem to be two distinct postures. In the “head-on threat,” which is simply the posture and movement that precedes a charge, the bull moves toward his opponent with his head held slightly to one side. The more slowly the challengers are moving, the farther to the side their heads are held. When they approach nearly straight on, either one bull submits by turning away or they bang heads. But when they approach slowly with their heads well to one side, they often stop close to, but not quite touching, each other and “nod-threat.” Nod-threatening bulls stand close enough to reach one another; their bodies may form a single straight line or an angle of up to ninety degrees, but in either case they turn their heads aside. From this position they can attack suddenly by hooking a horn into the opponent’s head. The hook always starts when the head is close to the ground, the muzzle tucked back. But in the threat itself, the head-low, muzzle-back position is only a brief interruption of a head-high stance: the bulls’ heads drop in a matched movement, then swing back up again, still to one side. A hooking attack may start at the bottom of any one of the down swings, but the opponent never seems to be caught off guard. After a series of such nods one animal may suddenly submit, ending the clash. Nod-threatening takes place most often between bulls that are not tending cows, as does the “broadside threat.” A bull in this posture keeps himself broadside to his opponent with his head held a little higher than normal. Usually his back is arched and he is bellowing. If he moves, he does so slowly, in short, stiff steps that keep him broadside to his opponent. Often two bulls will threaten by standing parallel to each other just a few feet apart. Only rarely does this threat lead to a fight. The encounter may be long as threats go, lasting up to a minute or more, but one of the animals almost always submits. /////////////////////////////////////////////////////////////////////////////////////bison All bison submission signals are variations on a theme: the submitting bull turns away. Sometimes it’s a 180-degree turn followed by a galloping retreat. At other times it’s an abbreviated swing of the head and neck to one side. When it involves a go-degree turn, the submitting animal ends up in the same general position as one who is threatening broadside. But it’s easy to tell the difference. In submission the bull’s head is usually low, muzzle extended as if to graze-and sometimes he does graze-and the bull is silent. Whatever form the submission signal takes, it almost always stops the threats or attack immediately.


How would a winning bull penalize himself by polishing off a loser? In fact, he would be deprived of two precious commodities: time and energy. The breeding season, when most conflicts take place, is limited, and time spent fighting, even a mop-up operation, is time lost from breeding. Fights to the finish would take even more energy, and that’s in shorter supply than you might imagine. When you see bulls in the middle of summer, in the midst of tall grass and warm sunshine, their good health and nutrition seem assured. But bison are northern animals, one of the most northern of the cattle family. They have adapted to a climate where food is scarce through long winter months. Bulls die during the winter if fall catches them without enough energy stored as body fat. As it is, the breeding season takes a lot of energy. Mature males lose an average of 200 pounds between June and October. If every fight were long and rough and ended in a cross-country chase, bison bulls, winners and losers alike, might well die before spring renewed the plains.


The prolonged forewarnings, the reluctance to fight, and the generosity to losers are neither the last noble vestiges of chivalry in our time nor nature’s way of exhorting humans to live on a higher ethical plane. Rather, they are carefully balanced behavioral adjustments to the social and ecological circumstances in which the competition between bulls evolved.


The older they get, the more likely they are to take the risks of combat in order to tend a breedable cow-not because older mature bulls are more likely to win than younger mature bulls, but because they have less to lose. Thereby hangs an intriguing budgeting issue, which might be titled “How to spend your life the way that buys the most descendants.” It’s an investment program in which your life is your capital and the return is your offspring’s offspring. For male bison, producing offspring usually involves conflict. Each such conflict puts their lives at risk. A bull bison’s optimal investment strategy weighs possible losses against possible gains and decides how much risk is prudent. He’s balancing making a killing against getting killed. Now, a male is not going to live forever, so an optimal strategy must be age sensitive. The younger he is, the more time and future opportunities he stands to lose if he dies. So he should invest cautiously when he’s young and has more to lose, but more and more boldly as he gets older and has less to lose. Bison behavior tracks this straightforward logic-the old bulls are the bold bulls. /////////////////////////////////////////////////////////////////////////////////////bison The way to a bull’s enthusiastic attendance is through his vomernasal organ, a sensory organ found in many mammals; it has an opening in the roof of the mouth. Cows’ urine is full of facts about how near ovulation is. The bull’s vomernasal organ seems specialized for an analysis of female urine chemistry that provides information on when a female will be ready to breed. But while bulls will joust seriously to get some female urine on their vomernasal organ, I’ve never noticed that females go out of their way to present it. However, I have many times seen bulls during the rut bring a resting cow to her feet by prodding her belly gently but firmly with a horn. The cows arise, with what I take to be resignation, and often urinate in a minute or two. The bull thrusts his muzzle into the stream of urine, then elevates his head, upper lip curled, tongue fluttering inside his mouth, his whole demeanor suggesting a gourmet’s appreciation of a fine wine. If he goes from lip-curling to tending, the chances are good that the cow will breed sometime that day.


We call the several hours before the cow breeds pre-estrus, and bulls that test the urine of pre-estrous cows are likely to try to spend the next few hours with her. That’s not easy to do. Pre-estrous cows become restless-breaking away from a tending bull and running through the herd. A running cow attracts bulls, and a string of them are soon following her just as a tail follows its comet. When she stops they gather and quickly sort out who among the present company gets to stand by his cow. The cow’s best shot at having many grandchildren is to have sons that can claim a cow just as this bull claimed her. If we assume “like father, like son,” he is the best candidate in the immediate circle-but the cow may well make him prove it again with another run through the herd. /////////////////////////////////////////////////////////////////////////////////////bison

the lower the tending bull’s rank, the more likely it was that the tended cow would run. In addition, cows that ran usually ended up with a bull that ranked higher than the one they ran from.


Tending pairs are unveiled as the movement of a grazing herd leaves them behind. Study a pair and you will see the cow grazing a bit, looking fretfully toward the increasingly distant herd. A big bull stands beside her, moving to block her when she sets off after the departing herd. He moves like a basketball player staying between a dribbling point guard and the goal. Sometimes she allows him to hold her in place, but “allows” is the operative word. His moves to block her are quick and graceful, but she is still quicker and more graceful. If she stays it’s because she has chosen-or at least settled for-him, not because he has chosen her. She may head straight for another tending bull. When Jerry Wolff compared the ranks of the bulls left to those approached, he found the cows were usually approaching a higher ranking bull. That’s one of the forms of choice a cow has, and it makes sense for her to be as choosy as she can manage to be. /////////////////////////////////////////////////////////////////////////////////////bison We don’t yet know what cues besides age the cow may use in making her choice. Could all that bellowing make a difference as to which bull is standing beside her when she stops running? Could it work like some birdsongs or frog croaks-a clue to the female about who might be a better mate? The bulls don’t seem to be sending a signal-they appear only to bellow to other bulls. They seldom bellow unless they already have a cow, are trying to displace a bull that has one, or are in the midst of a dominance contest. /////////////////////////////////////////////////////////////////////////////////////bison However important bellows may be to a resistant cow, her priorities and behavior change as ovulation approaches. The time of choosing is a period of conflict between the cow and the many courting bulls. The more competitors, the better for her but the worse for him. His earlier behavior minimized the number, hers maximized it. But now their interests coincide, and they must cooperate and collaborate. Often the cow redirects the relationship. Her physiology is changing fast, altering her behavior along with it. Now, instead of breaking into a gallop every time the bull is distracted by a challenger, she follows him, and when he has disposed of the distraction she stands close, perhaps even positions herself in front of him. If he continues to glower round at the competition instead of mounting her, she may announce her readiness to breed by licking him or by sticking a horn in his ribs and prying upward-extracting from the bull a grunt, a tuft of hair, and more attention. She may even mount him, and when he begins to mount her she squirts forward like a stepped-on bar of wet soap, but plants her feet and moves her tail to one side. Even so he may half mount, then drop off several times before he catches on and copulates. Bison sex does not involve a lingering mingling of mucous membranes. He clamps his forelegs around her ribs and penetrates with a lunge. The bull almost always ejaculates within five seconds of intromission (I timed it from movies of the event). His last pelvic thrust is driven home by a contraction of his abdominal muscles so strong that it jerks his hind feet forward and completely clear of the ground, making the 1,100-pound cow’s hindquarters suddenly support an extra ton of buffalo. Brief though the encounter is, it’s usually enough for the cow. She staggers under his weight, not infrequently limps for a while afterward, and four times out of five rejects further attempts by this or any other bull to mount her again for the coming twelve months.


In a well-nourished herd, 85 to 90% of the mature cows will bear a calf in the spring. Breeding season moves at a spanking pace. I’ve seen half the cows breed in the peak four days.


While breeding, bulls lose 10 to 15 percent of their body weight-mostly fat they will dearly miss in the coming winter. But the potential rewards are also enormous. The winning bulls win big. One year I saw one bull breed five cows while others bred none-one-third of the bulls sired two-thirds of the coming spring’s calves. Over three years Jerry Wolff saw one bull breed sixteen cows, while another never bred. The biologists Joel Berger and Carol Cunningham followed a herd for four years and saw one bull breed twenty-eight times while others never bred.


more and more of the bulls drift away to concentrate on providing their complicated digestive system with the fodder it will convert to fat to carry them through the winter. Their interactions change from constant confrontation to nearly invariable tolerance or passive avoidance. They’re not looking for any trouble, and, in the two months following the rut, they come to look a lot less like trouble. The magnificent, menacing mass of hair on their forehead and between their horns, the flowing beard, and the dancing pantaloons that gave advancing bulls such presence are gone. Much of the hair between their horns was barbered away-caught between rubbing horns and sheared off during fights. But the rest of that hair, the beard and the pantaloons, simply falls out after the rut ends and before winter starts. Only mature bulls molt this way, not cows and not even young bulls. Perhaps the hair loss is triggered by the stress of the rut-and perhaps instead, or in addition, it de-escalates the tension between the bulls: each benefits by looking less big-male threatening


Storing and using fat is somewhat inefficient. Converting digested food to fat uses some of the food’s energy, and converting it back to usable energy requires still more. But what the process lacks in efficiency it makes up in reliability. It makes it possible to survive lean times like the hard winters that always lie ahead


dominance relationships between the cows are no laughing matter. While there’s very little violence, there’s lots more subtle action. Alan counted aggressive interactions and saw two per cow-hour, ranging from a subordinate withdrawing to a dominant swinging her horns or lunging. The cows are under social pressure, expressed in the physical and social distance between neighbors. As is so often true of participants in relationships, they want to be close, but not too close. The closer a cow’s neighbors, the less the danger from wolves but the more the competition-for food, wallows, and water. Being close takes a lot of fine-tuning. Every step brings you closer or takes you farther away from several others, all of whom are also fine-tuning the distance they are from you. Physically, a buffalo cow just plods across ground and through air. But socially, it’s as though the air between each two cows were contained in transparent bags that compress and expand as each animal moves closer to or farther from a neighbor. The pressure inside the bags depends on the relationship between a cow and each of her neighbors; and since the relationship is not symmetrical, the pressure of the “same” bag is different for each of the cows. The dominant member of a pair may feel a little pressure when stepping toward her neighbor, while the subordinate may feel intense pressure when stepping toward the dominant, and not move as far. In addition, the cows can vary that stable, baseline pressure. A deferential head duck by the subordinate decreases the pressure for both; a threatening head swing by the dominant raises the pressure for the subordinate. The cows aren’t seeking an absence of pressure. If they can’t feel any there they find somebody. And up to an optimal point, the more pressures they can feel the better. Being a dominant member of a group has high potential payoff.


In Yellowstone Park, subordinates searched more and harvested less than dominants. Feast and famine were regular visitors to the Great Plains, with wet weather in some years and drought in others. In drought years every mouthful became precious to a cow eating to store enough fat to trigger ovulation and to carry a growing fetus through a hard winter. Dominance would have a big payoff in those years. And dominance would pay off any time that the snow was deep. Foraging bison sweep the snow from the grass by swinging their heads from side to side and using their muzzles as plows. They clear little craters in the snow and eat the grass at the bottom. At least, they eat that grass unless and until a dominant makes them move on and takes over that patch. A dominant will eat everything it clears and some that it doesn’t clear. A subordinate will eat only part of what it clears. That difference can be really big at crucial times. All other things being equal, the dominants will get fatter and the subordinates will get leaner. So the cows are interacting constantly, dominants and subordinates in a careful dance of distance; and being the dominant is worthwhile.


2-year-olds dominated 1-year-olds, and 3-year-olds dominated 2-year-olds; through age eight, all older cows dominated all younger ones. When they were young, of course, the older cows were also bigger than the younger cows. But by the time they were 3 years old that was no longer so, for they’d reached their full size. Yet 3-year-olds, even when bigger, didn’t dominate 6-year-olds.

/////////////////////////////////////////////////////////////////////////////////////bison it’s typical of a dominance system that the dominant individuals launch a steady stream of preemptive bullyings-sort of like those “Don’t even think about it” admonitions.


on Catalina only about 30% annually were giving birth. We captured 7 cows in a corral, determined their weight and age, and then hung radio transmitters around their necks and watched them. In a corral the cows had a strict dominance hierarchy. That hierarchy correlated perfectly with body weight: every cow dominated every lighter cow and was subordinate to every heavier one. Weight was all that mattered-age was irrelevant. Dominant cows ate better than subordinate, going through the oat hay in the feed troughs to get the grain that fell from the shattered heads and leaving the straw for the less dominant who were waiting their turn. After a few days of watching, we turned the cows back to the Range and followed them for four years. They went their separate ways, and we only rarely saw them together again. The more dominant they were in that corral for those few days, the more calves they had. The heaviest, most dominant cows calved every year; the lightest, most subordinate not at all. That is a huge difference. Natural selection is nothing more than some individuals rearing more offspring than others.


On the National Bison Range calves are born in April and May-spring /////////////////////////////////////////////////////////////////////////////////////bison Within a minute or two, as soon as his mother has freed him from the membrane that surrounded him in the womb, he begins a frantic-seeming struggle to get to his feet. He gets halfway up several times, and falls forward, backward, and sideways. I think, “Take it easy, little one, rest a minute. There’s no rush!” But the brain that has guided calves to adulthood for thousands of generations knows better. The calf hasn’t got a minute to spare. Wolves may arrive any moment. A late winter storm could drop six inches of snow tonight, and winter is certain to return in a few months. Winter and wolves. These ancient forces selected which among calves past would bear or sire another generation. And so they have shaped this calf-bones, brains, and behavior. To survive them the calf must grow: bigger, faster, fatter. So much growing to do, in so little time.


Adult bison spend a good part of their day ruminating; it’s an essential part of their digestion. But bison calves don’t ruminate for the first three months.


The calf needs to stay close to its mother, and to nurse. Evolution not only made nursing a necessity but set up a positive feedback loop. Nursing releases oxytocin, so the more the calf nurses the more mother loves it; and the more she loves it the more she allows it to nurse. /////////////////////////////////////////////////////////////////////////////////////bison

A bison calf’s first priority is to get to its feet and walk. By the stopwatch I kept time with as I watched a dozen births, that takes all of seven or eight minutes. An hour-old calf can scamper pretty well.


The bouncing baby bison doesn’t bounce aimlessly. It bounces toward something big and close. Mom is big and close and the ball usually bounces her way. But sometimes it fixes its eye on some other bison that passes by and rushes after it. Then mother chases both down and retrieves her young. A calf a few months old that loses its mother will attach itself to anything large and moving. An orphan calf followed Captain Meriwether Lewis all one afternoon as he walked west beside the Missouri River.


Many animals that move in herds or flocks have a call that signals with much the same effect of a human crying out, “I’m here; where are you?”


You hear their call occasionally while the animals are grazing, more frequently as a group of cows and calves walk along as they’re going somewhere-say to water. You hear a lot of grunting when a herd has just stampeded, separating cows and calves. Mothers and calves grunt to each other across a post stampede herd and track the right-sounding voice they hear to a reunion. The grunts that are so alike to our ears are different enough to theirs to convey identity-like a familiar voice saying hello when answering your phone call. But like someone responding to an on-the-phone hello, the hearer sometimes gets it wrong. I’ve several times seen a cow and a calf exchange grunts across a herd, make their way through it and come together, noses extended, only to fail the gold standard-the sniff test.


To measure the life span of a relationship, you must record first its birth, then its death. It’s easy to say when a cow-calf relationship begins, but harder to say when it is over. So we rely on proximity-inferring that the closer the bodies, the closer the relationship.


mothers must choose where to give birth. She and the calf need some way to ensure that each develops a relationship with the right other individual-smells the right smell, hears the right voice. For though they have been intensely connected physiologically-sharing one body and one blood supply-socially they are complete strangers. They must create the relationship quickly and surely, before the precocious calf becomes so mobile that it mingles with others that look and sound very like it. Cows can make sure of that privacy by being alone when they give birth. On Catalina Island most cows gave birth in solitude, usually among bushes, scrub oak, ceanothus, or coast live oak trees. There they were hard to see. They had both privacy and shelter from prying eyes-they had cover. But on the National Bison Range most cows stayed in their herd to give birth. There were exceptions to both rules, but the general patterns showed a striking distinction between the two places. This difference must have a cause, and my reasoning centers around the trade-offs between privacy and predation. Wolves hunt mostly by sight. If wolves are your worry, then being out of their sight is best. If there are bushes or trees you can hide among them. But if the tallest plants are ankle-high grasses, the only thing big enough to hide behind is another bison-or better still, a bunch of bison. On the National Bison Range I was watching cows give birth on a grassland; on Catalina Island they were giving birth in a coastal scrub community.


Selection has prepared a pregnant mother to prepare for another calf. Part of that preparation takes the form of ceasing to invest in her current calf so she can rebuild herself to deliver a healthy calf in just nine months. Thus the best deal for the cow is to invest less in this calf so she can invest more in the calf to come. She’s equally related to both, and to her calves that may come even further in the future. That’s not the best deal for the current calf. Mother’s new calf is unlikely to be closer than a half sibling-sharing one-fourth of its genes. All things considered, its best deal is for mother to continue to invest in it no matter the cost to its future half siblings. The result is a classic conflict of genetic interest. Pregnancy is crunch time. Now the cow has one calf at her udder and one in her womb. Her resources-her energy and her body’s tissues-are finite, and she must divide them between her two calves. Wendy’s pregnant cows’ behavior toward the one at their udder changed sharply, unlike the behavior of the mothers that didn’t get pregnant. Through the next three months (until the calf was six months old), pregnant mothers were more than twice as aggressive toward their calves when they nursed and attempted to nurse. From six months on, the differences were even more dramatic. /////////////////////////////////////////////////////////////////////////////////////bison the calf isn’t just pushed away, it also walks away-choosing to spend more and more time with age-mates and getting more and more of its nutrition from the grasses it grazes. Sons become mere acquaintances first, but daughters eventually do too, when they have their first calf, if not before. Each is pursuing the path that will maximize the number of its genes in the next generation. They have moved on.


Harvey Wallbanger, a flesh-and-blood buffalo, regularly showed his heels to racehorses in the 440-yard dash. Harvey’s triumph would not have surprised the Sioux, Crow, Black-feet, Comanches, and Cheyennes who hunted buffalo from horseback for nearly two centuries. While most of their horses could overtake one buffalo, only a few could overtake several buffalo in one chase. A buffalo’s skinny rump and long front legs give it a long-enduring stride-a good match for a coursing predator like the wolf. It is an animal faster than, well, some speeding racehorses, and able to leap tall road cuts at a single bound.


Management installed some cattle guards on the National Bison range. They were working fine for buffalo cows and calves, but not very well for bulls. Bulls were getting past them somehow, and one day I saw how. A bull walked calmly up the road to a cattle guard, stood placidly on one side of it, then hopped-no other word would really describe it-across, landing on all four feet on the other side. This hop had to be long enough to deposit his hind feet on the far side of the cattle guard, so he cleared the width of the cattle guard plus the distance from his front feet to his rear feet, say another six feet, for a total of fourteen feet. A very impressive standing broad jump. Well, at least I was impressed. If the bull was impressed, it didn’t show. He stood where he had landed for a quiet moment, then, with an air of “been here, done this,” cropped a mouthful of grass from the side of the road and walked on-patiently and efficiently.


National Bison Range personnel countered the buffalo hop strategy by placing 2 cattle guards end to end. Now a bull would have to hop 16 plus 6 feet; and so far as I know, none ever did. But buffalo bulldom had not exhausted the arrows in its quiver. One day in breeding season I pulled my ancient Jeep to the side of the road, just after passing through one of these amplified cattle guards, and sat looking at the herd ahead of me. From behind came a distinct pinging, as though someone were tapping something metal with a piece of wood. A bull’s image filled most of my rearview mirror. He was in the middle of the cattle guard, placing his feet delicately, cautiously, one at a time but still confidently, so they were centered on the narrow bars of the cattle guard as he walked across with all the poise, and a good bit of the daring, of a man on a tightrope. I would not have been any more astonished if he had also been singing “Tiptoe through the Tulips” in a friendly falsetto. When he reached solid ground he walked past me and joined the herd, leaving me to ponder the demonstration of footwork finesse I had just witnessed and somehow make it fit with the demonstrations of brute power I had also seen. For while buffalo leaps and sprints are spectacular, walking is the athletic talent that brings the animals to food and water day after day. Bison are roamers. Even in the confined spaces where they live today, they will travel ten or twelve miles overnight. On the Great Plains they may have traveled hundreds of miles from season to season-perhaps searching for a better place to spend the winter, or for a location with fewer human beings. They surely gained something from each step of those journeys, but (and here is where a physical feat is required) to be profitable each had to gain them enough to offset its costs. And the cost is high; bulls weigh about a ton. When a vehicle that size is fueled with blades of grass, every blade has to count. So the athletic challenge becomes like one of those competitions to see how far a vehicle can travel on a gallon of gas. It’s all about efficiency-getting the most out of every drop of gas or blade of grass. Why is it that an animal that runs so fast walks so slow? It’s all about energy. Buffalo, and just about everything else that walks, set a pace that matches the natural period of the pendulum constituted by its leg. A buffalo’s leg, like yours and mine, swings forward and back as the animal walks, so it’s a pendulum.


At its natural period pace a buffalo, or any other 4-footed beast, can recover 35 to 50% of the energy put into each stride. But when it comes to walking, two legs are better. Bipedal striders (creatures like ostriches and us) recover more, maybe as much as 70% of each stride’s energy just by walking naturally.


Harvey Wallbanger didn’t walk away from those racehorses. Both parties were galloping flat out for a quarter of a mile, and both could gallop-a little more slowly, to be sure-for miles and miles, as most hoofed animals can. How do they get the energy? By conserving it. This illustrates not the pendulum effect, since the bison’s legs are moving much faster than their natural period, but more a pogo stick effect. As their feet land, they store the force of gravity in tendons and ligaments threaded the long way around the joints in their legs. When their legs flex with gravity, those ligaments and tendons stretch like the spring on a screen door, and that energy is recovered as the leg straightens for the next step.


Sheep can recover about 30% of their running energy this way, and camels may recover 50%. Buffalo fall somewhere in that range. We humans don’t have the feet for this feat. Bison are always on their toes: that joint about a third of the way up their leg isn’t a backward knee but the heel of their foot, and the tendon from their real knee to their toes is long and stretchy. /////////////////////////////////////////////////////////////////////////////////////bison A bull has to twist and turn-quickly enough to protect his own flanks, quickly enough to get a horn into his opponent’s flank. Selection is intense. Bulls are wounded every breeding season, and in most years 5 or 6 percent of the mature bulls in any population die of their wounds. So the bulls are built to be quick in battle. To protect their body with their head, they need to pivot around their front feet. They have a great form for that function: much of their weight is centered over their front legs-their diminutive rear end is balanced in part by their massive head and neck. And the weight of their head is partly suspended from a point above their shoulders.


There, rays of bone a foot long (called vertebral processes) project up from their vertebrae and anchor a tendon that attaches to the rear of the skull. This efficiently supports the transfer of their head’s weight to their front feet, on which they pirouette on the sod like a hockey player on ice.

/////////////////////////////////////////////////////////////////////////////////////bison many plants produce tannin, which does nothing for the plant but makes it difficult for the animal that eats it to digest proteins. Many plant eaters, including humans, have evolved a countermeasure-our saliva contains a molecule that binds with tannin and neutralizes it. The astringent taste of the neutralized tannin gives a sip of red wine its special flavor.


Grass hasn’t evolved tannin, but it stores most of its carbohydrates as cellulose, and until the cellulose has been digested the carbohydrates are not available. In turn, most of the Great Plains’ big animals-bison, antelope, deer, and elk-counter cellulose with rumination, which turns grass into gas: figurative gas, as fuel to run their physical systems, and literal gas, as methane. Digesting anything is a strictly chemical matter of subjecting it to an enzyme that breaks certain molecular bonds, simple enough if you have the right enzyme. Put the food in your digestive tract, secrete the enzyme. Neither you nor I can secrete an enzyme that can digest cellulose. As a matter of fact, bison don’t secrete such an enzyme either, but they rely on a method as good and in some ways better: they enlist colonies of bacteria.


A third of mature bulls have at least one rib that has been broken and has healed.


WALLOWING. All bison wallow several times a day in summer, filling their hair with dust. The dust probably discourages insects and may reduce the bison’s body temperature.

/////////////////////////////////////////////////////////////////////////////////////bison Bison cool their bodies by evaporating water from their lungs. On hot summer days they need a lot of water. On Catalina Island, cows go to water twice a day, drinking four to six gallons at a time. Bulls there drink once a day in the summer. /////////////////////////////////////////////////////////////////////////////////////bison WILD BULL RESISTING ROUNDUP The bull pictured is reacting to men trying to move him through a corral on the National Bison Range during the annual roundup. Handling wild bison is difficult, dangerous, and expensive. Domestication will select for more tractable-hence less wild-animals. This bull’s behavior will be tolerated in this publicly owned herd, but a rancher would be compelled to shoot him. Some buffalo, usually castrated males, have been trained to carry a rider or pull a cart. They remain dangerous.


Bison are better suited to western grasslands than are cattle, requiring less care and doing less damage. More than 95 percent of bison in North America are privately owned and live on ranches. There selective breeding will produce a domesticated form of bison with little wildness left.


fermentation bacteria have waste products, which include alcohol. It’s a sobering fact that 12 or 13 percent of a bottle of Dom Perignon Champagne is bacteria pee.


For the bison a percentage of bacteria waste products that high would be a calamity, because it would mean that the bacteria were themselves using the energy their enzymes were releasing. Here we come to one of those built-in conflicts of interest that are part of nearly all relationships. Up to the point of converting cellulose to usable carbos and fatty acids, bison and bacteria have the same goals and collaborate. But now each has its own uses for the energy the enzymes have released-now they compete. It has to be a restrained competition, because both would starve if either were to get all the energy. Yet within the rumen, subtly different lines of bacteria must be striving to win a bigger share of the goodies. The bacteria-on-bacteria competition takes place in a friendly environment-the bison’s rumen-so the bison, being the environment as well as collaborator and competitor, has leverage that makes up for its slower evolutionary rate.


Bison don’t limit their bacteria’s food, but they severely limit their oxygen and their time. Some bacteria-anaerobic bacteria-can function without oxygen, but they function slowly. In time they would use up the energy they have released from the grass, so bison don’t give them time. They move the grass on out of the rumen after two or three days, pushing the partially digested food, and some of the bacteria that digested it to that point, further on. In the stomach, their own enzymes finish the job on the plants and digest some of the helpful bacteria as well. Timing is everything in this matter, and the ruminants have the timing down so well that they get about 90% of the energy for themselves. The mechanics of rumination are a bit inelegant. The ruminant assists the process by chewing its food after swallowing it-the bison brings up fist-sized wads of partially digested grass (cuds) from its rumen and chews them while lying at rest. If Buffalo Bill and the Czarevitch had sat in their saddles and contemplated a resting bison they’d have seen this; bison spend hours every day doing it. Although cud chewing-ruminating-gives them a faraway-focused, meditative, serene sort of look, it isn’t an elegant activity. But as an adaptation, rumination is elegance itself.


The immediate products of bison digestion are heat, energy, and tissue maintenance for the digesters’ bodies. The final end products of bison digestion are buffalo calves and buffalo chips.


Analyzing parasites is the most straightforward part of this study-just look and count. Figuring out what bison are eating is also straightforward, though rather more time-consuming. The cell walls of plants are pretty distinctive and pretty tough. You pick through the chips and locate cell walls. You compare the cell walls to the cell walls of plants from your reference collection-representatives of each plant that grows where the bison are feeding. The reference collection is needed to set some boundaries on your search for matches. And that’s it. You can find out how many of the plants in its habitat a bison feeds on and, by comparing the percentage appearing in the chips with the percentage in the field, estimate which plants the bison favors.


Why aren’t all buffalo white? White is a good summer color. It reflects the sun’s heat, and that heat is a fact of life for bison. They evolved in the grasslands, where summer sunshine is plentiful and shade is nonexistent; bison spend most of the long summer days absorbing the sun’s heat into their dark coats. White is also a good winter color. Some rabbits turn white in the winter to blend with the snow, and so do some of the weasels that stalk them. Wolves hunt bison all winter long. Wouldn’t blending with the background be a good idea?


But not only are white buffalo rare, they don’t seem to do well.


Bison seldom if ever die of heat, but they often die of cold. The dark coat that makes the sun a nuisance in summer may be a lifesaver in winter. Bison evolved in really terrible winters; and even now, especially severe winters kill many of the old and the young. The sun is low and the days are short, but every calorie of heat absorbed from the sun is a calorie the bison does not have to manufacture from the scarce forage-forage that must be won by sweeping the snow from each bite with that heavy head-or drawn from its precious cache of calories in the form of stored fat. Like deer and elk, bison cut their energy output by losing their appetite. They eat less and produce less heat-and not just because food is scarcer in winter. Even when they can have all they want from full feeding troughs in an experimenter’s corral, they eat 30 percent less food and produce 30 percent less heat in February and March than in April and May. /////////////////////////////////////////////////////////////////////////////////////bison

A buffalo robe was a possession prized by humans dwelling on the North American plains. It can keep you warm in a terrible storm. Cattle have replaced the buffalo, but there isn’t much point in bundling up in a cattle robe. The buffalo robe’s superiority is quite straightforward-a square inch of buffalo skin has ten times as many hairs growing from it as a square inch of cow skin. The difference, when temperatures and fat stores are low, is the difference between life and death. But when summer arrives there is a price to pay. The North American plains are a place of extreme heat as well as extreme cold. It’s a bit like jumping from the deep freeze to the frying pan, and the challenge in summer is keeping cool. The first thing the bison do is shed their winter coats. The long, twisted, almost woolly hair of winter molts, and from the front shoulder back a sleek coat of short hair is revealed. It insulates only a little, allowing the nearly ceaseless wind of North America’s grassland to blow away body heat. That surely helps; but still, the sun is hot, their dark hair absorbs its heat, and they also produce heat as they ferment their food and move around. If they couldn’t get rid of the heat they generate and the heat they accumulate, they would soon be walking pot roasts.


Bison don’t sweat, but they breathe, and lots of animals, again including humans, lose heat by evaporating water in their lungs. /////////////////////////////////////////////////////////////////////////////////////bison

Evaporative cooling works well, but it has one major cost. You have to go through a lot of water in order that a lot of water can go through you. That internal supply must be replenished regularly. Surely the bison can do something to reduce the number of trips to water. Of course they could find some shade, but they don’t seem much inclined to. It’s astonishingly common to see them lying in the hot sun only twenty feet from dense shade.


Bison wallow in the summer, especially during the middle of the day. Wallowing puts soil into and onto their coat. They can work so much nice, dry, powdery soil into their coat that as they walk away from the wallow it cascades down, jarred loose by each step. Like most old-timey bison watchers, I have always thought they were wallowing to make their hair a lousy place for lice and other parasites. I still think that’s likely, but wallowing may also lower their heat load. Elephants have a heat problem much like bison have, and we know that a good coat of dirt is one of their solutions. /////////////////////////////////////////////////////////////////////////////////////bison There was a witness, the dead bull himself, and though he was silenced 36,000 years ago, he has testified through the forensic skills of the paleontologist Dale Guthrie. He is not one of the anonymous dead; he has a name: Blue Babe. He is here to tell his story because after the lions killed him and made a meal of his hump, a mud slide buried him. The mud froze, and the mud and Blue Babe remained frozen until a gold miner washed away the mud and revealed the mummy one July day in 1979. Copper precipitation had given Blue Babe’s hide a blue tint and his hump had gone to fill the lions’ stomachs, but the rest of him was remarkably well preserved. The tooth and claw marks in his hide were still so clear that Dale could take an American lion’s skull, place its canine teeth on the marks left by the killer’s canines, and see a perfect match. Even the flesh was so well preserved that when the corpse had yielded all its secrets Dale and his colleagues made an acceptable stew with a bit of the meat. /////////////////////////////////////////////////////////////////////////////////////bison

Blue Babe was a Bison prisons-at least two phylogenetic steps back from today’s Bison bison. He was very like his ancestors that came to North America from Siberia. It wasn’t a long journey. When the route was dry, bison could have walked from Siberia to Alaska in three or four days.


Bison branched off from the primitive cow family line-Leptobos-about a million years ago. The first bison were small-bodied, small-horned, fast-moving residents of forest edges and meadows. Gradually the bison line became northern specialists, able to live where other cattle couldn’t. They also became open grassland specialists. /////////////////////////////////////////////////////////////////////////////////////bison

A question springs to mind. Was there enough grass in North America to feed 100 million bison? Or, as an ecologist would put it, “What was the carrying capacity of the whole area bison lived in?” In still other words, what’s the biggest population the continent’s bison habitat could have supported? That won’t tell us how many were there-it just sets an upper limit;


In 1972 the zoologist Tom McHugh determined carrying capacity by starting with the total area of the central grasslands, 1,250,000 square miles, then took “a range manager’s” approach to keeping livestock numbers within carrying capacity. Using existing formulas developed for cattle, McHugh calculated conservatively to take dry years into account. He assumed that carrying capacity varied from 1 buffalo per 10 acres in the tall grass prairie just west of the Mississippi to 1 per 45 acres in the short-grass prairie just east of the Rocky Mountains. He got an overall average of 25 acres per buffalo, or 26 buffalo per square mile. That gives the Great Plains a carrying capacity of 32 million bison. McHugh deducted 4 million for competing grazers-pronghorn, elk, and prairie dogs-and added 2 million for bison living elsewhere, for a final estimate of a maximum of 30 million buffalo on the continent in primitive times.


Mary Meagher, a Park Service biologist who has studied Yellowstone’s bison for more than 40 years, has seen several winters kill 20% of the population. A bison population can have much bigger busts than booms. In fact, no bison population has ever grown faster than 20 percent a year even when it had zero predation and negligible winter kills. /////////////////////////////////////////////////////////////////////////////////////bison About all we can confidently say is that primitive America’s bison population was probably less than 30 million-perhaps, on average, 3 to 6 million less. /////////////////////////////////////////////////////////////////////////////////////bison

GRASSLAND ECOLOGY From southern Alberta to central Texas, from the Rocky Mountains to the Mississippi River, a sea of grass covered the middle of North America-the area called the Great Plains covered 15 percent of the entire continent. The bulk of primitive America’s bison population lived there. Plants conform to a simple general rule: where the clouds bring more water as rain and snow than the sun and wind can evaporate in an average year, trees grow. Grass grows where there is at least half as much precipitation as the sun and wind can evaporate. If there is so little precipitation or so much evaporation that grass can’t grow, you are standing in a desert. In a temperate climate like that of the American Prairie, a very rough rule of thumb is that more than ten but less than forty inches of precipitation per year makes for a grassland. But while fourteen inches might be plenty in northern Montana, it might be too little in southern Texas. The American Prairie is doubly rooted in the Rocky Mountains. The rise of the Rockies created a rain shadow favoring grassland over forest, and the soils the grasses grow in came largely from the Rockies. About half the original mass of today’s Rocky Mountains has eroded. Water, often in the form of ice, did most of the eroding, and moving water carried many of the eroded particles east as far as the looth meridian of longitude. The looth meridian lies just east of Pierre, South Dakota, and hits Dodge City, Kansas, almost dead center-about halfway across the central plains. But there was another great conveyor belt at work too: moving air-the prairie winds. Loess is wind-borne silt. The prevailing westerlies carried loess to and beyond the Mississippi. Nebraska and Kansas were almost completely covered by a thin layer (less than five feet deep) of loess. Take away plant cover and roots, stir the loess, and it’s ready to   ? 82 ? move again. What wind brings, the wind can take away. It was loess that the westerlies carried from the Midwest’s dust bowl to the Atlantic in the 19303. The central grassland’s native plants, along with dirt dwellers such as earthworms, modified those materials into fertile soil. But not always the same soil. Hudson Bay and the Gulf of Mexico are at sea level. The western edge of the American Prairie, just east of the foot of the Rocky Mountains, is nearly a mile high, and, located in the Rocky Mountains’ rain shadow, pretty dry. Every mile downslope, to the east, it’s lower, wetter, and warmer and the soil is darker-from brown in the west through chestnut to black at the eastern edge of the prairie. Ecologists divide the American Prairie into three regions, each named for its predominant grass. Other things being equal, the closer to the Rockies a given location is, the less rain it receives and the shorter its grass. At the foot of the Rockies-say Denver, Colorado, or Billings, Montana-you’re at the western edge of the short-grass prairie. Travel east to Kansas’s western border, and you’ll find the short-grass prairie blending with the mixed-grass prairie. It’s a blurred and shifting border, not at all precise, but nevertheless important. The mixed-grass prairie attracted more bison than either of the other two. It covered all but the eastern edge of the north-south tier of states starting with North Dakota and extending through South Dakota, Nebraska, Kansas, and Oklahoma and into central Texas. The tall grass prairie lies between the mixed-grass prairie and the Mississippi. During a long drought-say eight to ten years-the short-grass prairie moves east as its dry-adapted plants outcompete the taller, thirstier tall grass prairie plants. When the rain returns, the mixed-grass boundary region shifts west again. Dividing the central grasslands into sections can make each seem small. It helps to remember that the short-grass prairie alone is about the size of western Europe. The American Prairie’s grasses are deeply and broadly rooted in the soil: established for the long run. They’re perennials-their root systems are designed not for months but for decades. Only 10 percent of growth is above ground in leaves and seeds; 90 percent of growth is in the roots, and each plant sends about three-fourths of its carbon below ground into its roots. With so much energy stored below ground, the plant can persist   ? 83 ? through years-long droughts. In the wettest grassland, eight-foot-tall grasses such as Indian grass and big bluestem spread their hundreds of roots as far as six feet down into the deep black soil to tap the moisture accumulated there in past years. In the west, blue grama and buffalo grass send up stalks about ten inches tall and fill the soil below and beside them with roots outfitted with tiny hairs that absorb water from the upper thirty inches of soil, thereby capturing the moisture from even small storms.


For each buffalo the shift in weather meant hunger, less chance of reproducing, more chance of dying. For the bison as a whole it meant a shrinking population. But the dry years were what kept the prairie a grassland. If every year were wet, trees would grow, grass would go,


their bad luck was an inescapable part of the boom-and-bust cycle of all temperate grasslands. And it’s the bust part of that cycle that made sure the minerals from their bones nourished a grassland covered with living bison and not a woodland haunted by their ghosts. The wind-rippled grassland whose surface undulates from horizon to horizon strongly evokes a sea, but it’s a sea that can catch fire. Grass burns all in an instant. A dry stem glows red and turns to curling ash while you are still drawing a breath. When a wind pushes it, a prairie fire runs fast. The American Prairie has always burned.


For millions of years lightning caused combustion, but people began to burn the prairie several thousand years ago-often with buffalo in mind. Sometimes they used the flames to herd the bison, driving them to a place for easier and safer killing by people on foot. Sometimes they burned the grass so that new growth would attract bison to a more convenient killing place. Growth-stimulating fires were set in the spring when new growth would quickly replace the old. In the fall, new growth was up to six months away. Bison deserted the bare ground created by a fall fire until spring, and the people who hunted that ground faced starvation.


In tall grass prairie, where mature grasses and their litter intercept 99% of the sun’s rays before they reach the ground, fire creates a moment when a short plant’s leaves can nourish their roots. The plant community that rises from the ashes is richer in species and more complex. The grasses surge back from their roots-the soil two inches down would not have been warmed even two degrees Fahrenheit by the fire-but the new leaves are different from those whose ashes they rise through. Enough nitrogen is carried away in the smoke so that the new growth has a higher ratio of carbon to nitrogen. That makes it poorer forage than was the now-burned grass when it was newly growing, but better forage than the mature plants that burned. Fire decreases production in the short-grass prairies, where water limits growth. But in the tall grasses, where the failure of radiation to reach the soil limits growth, fire increases production. Fire interacts with grazing. In the mixed-grass prairie, little bluestem presents grazers with an in-your-face defense-stiff tillers (stalks) that the grazer must push through to get to the green leaves. Fire removes the tillers, and bison, which avoid tillered little bluestem, graze the new-growing little bluestem as readily as other grasses. The fire that consumed little bluestem’s defenses thus helped little bluestem’s competitors through the mechanism of bison grazing. The grasslands are as much creatures of the grazers as the grazers are creatures of the grasslands. Other, smaller, grazers also played a role. Grasshoppers, for example, were always present, and occasionally a tidal wave of Rocky Mountain locusts would roll east with the westerly wind, eating every blade of grass in a swath a hundred miles wide and hundreds of miles long. And below the surface nematodes, nibbling at the roots, ate more grass than everything else put together. Still, in their heyday, bison were big on the plains-big enough to be called a keystone species. Grassland has a reciprocal relationship with bison, though the reciprocity is somewhat roundabout. Bison aren’t very picky, but given the choice they will choose grass over forbs (i.e., herbs other than grass). That small preference makes a big difference to the grassland. In the tall grass prairie, grazing bison keep the dominant tall grasses such as big bluestem and Indian  grass short enough so other species can also grow. Consequently there are more plants representing more species where bison graze. Grasses resist being eaten. The tall grasses outgrow the grazers. In a few weeks they become tough, unpalatable, and protein poor. In the West, where there isn’t enough water to outgrow the grazers, buffalo grass employs the opposite strategy. It grows too short to be grazed easily, keeping its leaves low and tucking them back and down where they’re hard to reach. Grazing costs the grazed grasses much of their leaf structure-the photosynthetic, energy-producing part of the plant-and the plants react. They boost the photosynthesis of the remaining and replacement leaves to compensate. In the short term this strategy makes up for the lost tissue. In the long term there’s no free photosynthesis: the grasses boost their short-term output by dipping into their capital of stored nitrogen, and as that gets drawn down they’re less and less able to compensate. They need about two years’ rest to recharge their carbohydrate and nitrogen batteries from a big draw-down. Bison affect species composition in two ways. First, they wander. When they had the whole prairie to wander over, particular patches of grass probably had two-year rests fairly regularly, especially as bison choose areas where grasses are growing most vigorously. When the tall grass canopy is grazed off, the sunlight reaches the earth and the shorter plants do better. There are fewer individuals of more species after grazing-just as after fire. But grazing-stimulated growth in the western short grasses tends to eclipse smaller plants. Grazed short-grass prairie has more individuals of fewer species. Second, bison don’t just take away. They give something back-fertilizer. From a prairie plant’s point of view, urine is a bath of nitrogen dissolved in water-the answer to its prayers. The grasses’ leaves and stems would have eventually decomposed and returned the nitrogen to the soil, but after a longer delay and in a form that the plant would spend more energy using. Bison drawn to the close-clipped, nitrogen-rich grass in colonies of black-tailed prairie dogs leave a disproportionate amount of their digestive by-products there, thus transferring nitrogen from the rest of the prairie soil to prairie dog towns. Bison don’t just graze and eliminate on a prairie, they also wallow and die there. The soil from the wallow probably gets rid of some insects, possibly reduces the bison’s heat load, and certainly changes 75 to 150 square feet of habitat for the prairie plants. Wallowing lays the soil bare and compacts it. The compacted bowl of soil holds rainwater, creating a microenvironment in which seeds can sprout and seedlings of plants-sedges and rushes in tall grass prairie-that are otherwise rare on the prairie can grow. Some of these seeds are blown in by the prairie winds, others are carried there in the coats of the wallowing bison-perhaps picked up in another wallow. Bison maintain old wallows for years. Ecologists have even found wallow-shaped and -sized depressions in prairie soil 125 years after the last bison left a locality.


More than 99% of the tall grass prairie has been plowed; most of the world’s corn and much of its wheat grow there. The more arid the land, the less of it has been plowed. About 42 percent of mixed-grass prairie and about 29% of short-grass prairie have been converted either to cropland or to nonnative grass pastures. The native perennial grasslands made soil; an annual grassland spends it. A clump of native perennial bunchgrass eighteen inches across may have two miles of roots. They cling to the soil and it clings to them. That’s not true of many of the domesticated grasses that have been planted in its place-wheat, oats, barley, and corn are annual plants. They have evolved a radically different strategy. They live only long enough to produce a single crop of seeds. Instead of storing energy in their roots, they put it into their seeds. Since those are the parts of grasses we humans generally use most, we prefer annuals. But their roots are minimal, die each year, and don’t hold much soil. Raising cereal crops on the Great Plains trades soil for seeds. Today’s annual grasslands are spending the capital that the native grasslands had banked. Grain growers have ways to slow the erosion-crop rotation; cultivation that follows the hill’s contours; the alternation of strips of crop with strips of fallow, moisture-accumulating soil plowed at ninety degrees to the wind-but nothing yet stops it, let alone reverses it. Despite all the arts of modern agriculture, on most of the plains west of the looth meridian a money profit is possible only by running a soil deficit. It’s still possible for a few people to make a living most years, and to feed many more from the dwindling soil. But someday-someday soon in much of Great Plains country-there will be too little soil to produce food profitably. What then? Some people have a vision in which sizable parts of it go back to feeding buffalo, and they want to do it before so much soil is gone that the land will be barren.


A domestic line of bison would be gentler on the short-grass prairie than either wheat or cattle. They’ll walk further for food and trample stream banks less; even the more cup-shaped bottoms of their hooves shift the soil they step on a bit instead of just compressing it. Through them the grassland can produce food without being plowed, and thus without being washed away. /////////////////////////////////////////////////////////////////////////////////////bison

this development won’t do anything for the bison as a wild animal. If it isn’t done right it could harm wild bison. We must insulate wild bison by isolating them from domesticated bison. One place to do it right is in a Great Plains grassland park. /////////////////////////////////////////////////////////////////////////////////////bison At the top stands the alpha wolf, tyrant of all, tyrannized by none. A step below is the beta, tyrannizing all but the alpha and tyrannized only by him. At the bottom is a wolf that tyrannizes none and is tyrannized by all. It eats last, if at all, and is casually bullied by all other pack members many times each day. For those at the bottom of the hierarchy it’s a dog’s life in the worst sense. But that’s my perspective-the perspective of a Jacksonian democrat, focused on the underwolf. Viewing wolves from it is, in an important sense, simply silly. Judging wolves by our standards is as foolish as judging ourselves by theirs. The lone wolf is a romantic figure but a biological dead end, so even underwolves stay with the pack. They have no choice. For wild wolves, loyalty is life.


The other members of the pack, who are nearly always the dominant pair’s siblings or offspring, are the attending adults. For the subordinate, membership in the pack holds out the possibility of promotion to a top spot. Meanwhile aunts and uncles or brothers and sisters bring food back to the den and baby-sit the growing pups. Caring for pups born to their parents or siblings increases the representation of the family genetic complement in the next generation, so they’re also having a bit of reproductive success, though diluted by the distance of their kinship. /////////////////////////////////////////////////////////////////////////////////////bison

Wolves can kill cows, and do in the winter. They can even kill a bull in winter. But cows and bulls can injure or kill wolves. If a wolf is to make its living killing bison, it must choose a bison to kill every few days for the rest of its life.


Mature bison bulls are 2,000-pound athletes with sharp horns, hooves like sledgehammers, and a very short fuse. Their hide is thick, tough, inedible, and hard to chew through to get to the animal’s edible parts.


In Wood Buffalo Park, where the wolves live largely on bison, they kill only calves right through the summer. By fall half or more of each spring’s calves have fed wolves. It’s not likely that the wolves are doing this population some good by weeding out the unfit, unless being young and unlucky is a form of unfitness. The calves being weeded out are the unlucky plus, perhaps, a few that are a little short of specifically wolf-resistant traits-for example, always keeping somebody else between you and the wolves, or always having a tough and resourceful adult at your side. When mixed herds-cows and bulls together-travel, cows and their calves tend to journey in the safest area, front and center. Many of the survivors owe their lives to an alert and aggressive mother. She may have had help with her wolf problem, though probably not from another cow. When the wolves come it’s usually every cow for her own calf. But occasionally she can get help from bulls. During a marathon standoff in Wood Buffalo Park, four wolves spent eleven hours trying to kill the one calf in a small herd-the calf’s mother and fifteen bulls. Time and again the cow led the calf to, or the calf on its own ran to, one or more bulls. The bulls then charged the wolves, and sometimes surrounded and accompanied the calf. In the end, although the wolves were able to get their teeth on the calf eleven times, it was very much alive-even frisky-the next day. /////////////////////////////////////////////////////////////////////////////////////bison During the 11-hour siege in Wood Buffalo Park it was young bulls-too young to breed in the coming rut, let alone to have bred in last year’s rut-that most kept the wolves at bay. /////////////////////////////////////////////////////////////////////////////////////bison

the male I’m watching will eat the insects the bison flushes rather than feeding them to its babies, and the females accompanying the feet and muzzles of nearby bison will do the same. As their eggs become ready to lay, female buffalo birds scout around for a place to lay them in already feathered nests containing newly laid eggs-always of another species, because buffalo birds don’t make nests. So they lay their eggs in the nests of strangers who, if luck holds, will incubate their eggs and feed their babies. The bird people call such birds brood parasites, and they show up in the best of families. English cuckoos always display this behavior. Black ducks always do it. Goldeneye ducks sometimes do it. It’s an intriguing way of life, but it has its hazards. Some of the nest owners recognize the bad egg and toss  it out. But for the buffalo birds the approach gets around a big problem. Bison can travel tens of miles overnight; for the birds, that changes a five-minute trip to the corner grocery to a long search for a new food source that may be hours away. Buffalo bird nestlings need to eat most of their weight every day. The logistics of depending on beater buffalo for food makes rearing your brood yourself a chancy business. So traveling with the herd and being a brood parasite go together nicely.


A buffalo bird that has never heard the song can sing it. But there are many ways to sing any song, and he is open to suggestions. In fact, he is looking for them. He perches a foot or so from a female, fixes an intense gaze on her, and sings his song, first this way, then that, trying out styles. The song is short. At its end the female usually sits unmoved, and he sings again in a different style. But once in a while she flips a wing, ever so slightly, at the end of the song. The male is mildly electrified. He quickly repeats the song she just flipped over; and when she flips a few more times after hearing it, that becomes the song he sings.  With his song style perfected, he seems well launched on the royal road to romance, or at least the freeway to fertilization. But the song may get vetted one more time-by his bachelor buddies. He sings his song around them too. It may be a multipurpose song, saying he’s a fighter as well as a lover. His buddies’ reaction depends on his status. If he is the dominant male in the group, they just listen. But if he’s not, those that dominate him attack, and they keep on attacking after each song until he sings a less effective song-one that females are less likely to flip over. This second vetting biases the breeding toward the dominant males, because the songs a female flips to are the songs she will stand for when the singer tries to mount her and fertilize her eggs as they form.


A bison’s big body is the largest repository native to North America of the sun’s energy converted to flesh and blood. The size and numbers of their bodies made bison too big a resource to ignore, and many creatures have found a way to get a bit of the sun’s energy by tapping into the bison’s store. True, their sheer bigness thwarts many-coyotes, say, and even wolves-that might try to harvest this stored energy. But predators aren’t the only exploiters of bison. Like all big organisms they are a resource for hundreds of kinds of tiny life forms that use them in a variety of intriguing ways. And size is no protection at all from very small things-it just makes you a bigger target. /////////////////////////////////////////////////////////////////////////////////////bison Brucella abortus takes its species name from one of the ways it uses its host’s life to get its young into the next generation: it sometimes causes abortion. The infection is called brucellosis, and the fact that some wild bison have it is at the swirling center of disputes about how wild bison should be managed-indeed disputes about whether or not there should be any wild bison. Brucella abortus came to North America from Europe, inhabiting domestic cattle, and first began to inhabit bison in Yellowstone Park around 1917. It now infects many individuals of the two largest herds of wild bison remaining-those in Yellowstone Park in the United States and those in Wood Buffalo Park in Canada.


Every winter hundreds, sometimes many hundreds, of bison are shot on Yellowstone’s western boundary. This policy is designed to prevent their exposing to brucellosis the cattle that graze every summer on the largely public lands that surround Yellowstone.


Brucellosis can infect a wide range of mammals, some birds, and even some insects, but it tends to die out in most species. It’s transmitted from one species to another when an animal eats forage contaminated by an aborted fetus or contacts the fetus itself. The fluids in a colonized cow’s aborted fetus are loaded with B. abortus-billions of microbes in a tea-spoonful. Any mammal that gets these fluids in its mouth, nose, or even eyes can be infected. (Humans are a secondary host. We develop a fluctuating fever called “undulant fever”-my father’s mother got it as a child by drinking unpasturized milk.)


Brucellosis is not a catastrophic disease. Except for the occasional abortion, its symptoms are mild to nonexistent in infected cows, and it poses no meaningful threat to humans today. Cattle, elk, and bison all have the potential to transmit brucellosis to one another, and elk-to-cattle transmission has been demonstrated in a few cases. Brucellosis has been eliminated from cattle by testing every animal, destroying those that test positive, and vaccinating calves-usually just the female calves.


ticks use bison as a place to grow up. From the tick’s point of view, a buffalo is an effectively infinite bucket of blood from which, once you manage to insert your straw, you can suck a lifetime’s supply of nourishment. But first you have to catch your buffalo. It’s not easy being a tick, and few quests are successful. It’s mostly a waiting game. Take a larva’s first step: find a place where a buffalo will pass within reach of your front legs. On a prairie, the tip of a tall stem of grass is a good bet. Climb to the tip and hang on until either your minute supply of body moisture dries out, turning you into a tiny cornflake, or your prey brushes against your perch and you grab on. /////////////////////////////////////////////////////////////////////////////////////bison

the ticks must manage to hang on despite not being at all welcome. They’re serious parasites, after all-a single tick growing to maturity on a farmer’s calf costs the calf a pound and a half in growth. So the tick’s targets resist. A buffalo’s first line of defense is the hair coat that stands between the tick and its skin, and even for a tiny larva-the form winter ticks arrive in-this is a formidable barrier. Bison are very hairy. They have more primary hairs per square inch than any other members of their family-ten times as many as cattle-and a woolly undercoat as well. So even with a firm grip on the bison’s hair, the tick is on the outside trying to get in. Time is short because bison do many things that tend to terminate the relationship. The bison’s second line of defense is good grooming. They wallow, covering the tick with suffocating dust or scraping it off on the soil. They rub against trees or bushes, challenging the tick’s grip. They scratch their neck and head, even reaching between their horns, with their hind feet. And, probably the most formidable defense of all, the tongue or teeth sweep across the hair on paths dozens of ticks wide. It’s a wonder that any ticks break through to safety. In fact, few do. Bison have a small fraction of the ticks suffered by elk or moose living in the same habitat. Desperate as things are for a tick that grabs a mature bull or cow, they are much worse for the tick that happens to hitch its hopes to a calf.


Calves groom up to sixteen times as much as adults. It’s not because they have the energy to spare, it’s because they don’t have the energy to spare. A tick takes the same amount of energy from any bison, but that’s a much larger proportion of a calf’s total energy. The smaller the animal, whether it belongs to a small species or is simply young, the greater the relative cost per tick and the more vigorously the host employs anti-tick strategies. Hence, among bison, calves are the most inhospitable hosts. But bison can’t spend all their time defending themselves from ticks. They have to budget their time and energy to cover a lot of essential activities. How do they know how much time and energy to spend attacking ticks in each season?


the pronghorn buck vocalist was “Graybuck,” a male in the prime of life. When he came to a patch of bare ground a couple of feet long and half as wide he sniffed it, pawed it with one forefoot, straddled it, and urinated in it. Then he stepped forward to defecate in the same spot, showering down a handful of pellets that came to rest among hundreds of others he’d already dropped there. Those pellets were all his and, in a certain sense, that place was his.

/////////////////////////////////////////////////////////////////////////////////////bison He patrolled its boundaries, chased away intruders, and put his smell on it. In fact, to a more sensitive nose than ours, the place must have fairly reeked of him. Besides his urine and feces, he made it smell of him by anointing some of the plants with musky oil from a gland in his cheek. He’d take a tall stalk of mullein or goat weed into his mouth and then, having wet it, apply his scent from his cheek gland. /////////////////////////////////////////////////////////////////////////////////////bison it’s a safe bet that another pronghorn inhales a wealth of information from both the marked plant and the pawed dirt: who left the scent, how long ago, maybe even something about his physiological state-and the warning that any other males will be challenged here. The males had started all this in spring, and they would keep it up until September. Then, during a frantic two weeks, each mature female will take an interest in sex for a few hours-for the male attending the group just then, a moment worth seizing.


why make a big to-do about a particular area?


a pronghorn is picky-and has to be. Small bodies need less food, but they also need better food: more protein, fewer carbos, less lignin. Generally, the smaller a warm-blooded animal is, the more of its body’s warmth is lost to the air and, to compensate, the higher its basal metabolism must be. There is such a thing as a better class of grass. The growing part has more protein. So younger is better and the part nearest the roots is better, but what makes life possible for the pronghorn is a supply of forbs-small broadleaf plants growing among the grasses. They have more protein and less lignin. The pronghorn picks them out, one or two at a time, from the surrounding grass. From a field that’s 95 percent grass and 5 percent forbs, a pronghorn will eat half grass and half forbs.


Pronghorn have a narrow mouth that selects plants one at a time. The pronghorns’ perspective on forbs makes their relationship to a grassland very different from the bison’s. For the bison it’s just grass going on forever, but for the pronghorn there are patches of forbs growing among the grasses-more forbs in lower-lying, wetter ground and fewer on higher, drier, sunnier ground. The amount of food in such a patch is small, but so is a pronghorn. These patches make some parts of the grassland more attractive to pronghorn than other parts. Females spend more time in the better patches; so the better the patches the male defends, the better his chances of being the only male in the right place at the right time.


When the wind blows, its speed at the top of the mound is faster than at the ground-level entrance because the friction of ground and grass slows the wind so much that it’s significantly faster just a few inches above the surface. Prairie dogs shape the soil excavated from the burrow into a wide chimney that opens several inches-occasionally as much as two feet-above the surface at the front entrance. The faster wind over this chimney draws stagnant air out of the burrow, pulling fresh air in through the   ? 128 ? soil-level entrance. The air is fresh whenever the wind blows, and on the Great Plains that’s most of the time. These chimneys of soil draw buffalo as well as air. Bison go to a lot of effort to fill their hair with soil-probably it drives out insects, possibly it keeps them cool. And there’s nothing like a good rub on a prairie dog mound. Then there’s that really green grass. Prairie dogs are as much addicted to staying home as bison are to roaming. They both eat grass; but by grazing the same few square yards every day, prairie dogs keep the grass


and shorter grass is better grass. The closer the blade is to the roots, the higher the percentage of protein and the lower the percentage of cellulose it contains. Closely cropped grass is a necessity for prairie dogs and a treat for bison. So bison spend a lot of time in prairie dog towns, enjoying a snack, rolling on a mound or two, and resting and ruminating. The relationship appears pretty one-sided so far. Bison mangle the mounds and eat some of the short grass-they are vandals and breadbasket burglars. But bison also bring something to the party-or, more precisely, leave something: grass processed into fertilizer form. It’s an excellent source of nitrogen. The longer bison hang around the prairie dog town the more they distribute there, and the more they distribute the greener the grass grows. Of course, buffalo chips don’t produce a fertilizing effect as quickly as, say, Miracle-Gro, so the bison are a little like a dinner guest bringing a bottle of wine so new it must be aged a few years to be palatable. Still, prairie dog towns stay put for generation after generation, and buffalo chips are a gift that keeps on giving. Buffalo urine is good for the grass too, and it takes effect right away. But perhaps the bison’s biggest contribution to prairie dog towns is to make them possible. Everywhere but in the western short-grass region, prairie dogs depended on bison to get the grass short enough for them to live there. Prairie dogs won’t live in tall grass. Tall grass is less nutritious, and it also hides approaching predators. Where the taller grasses grew, the founding grazers of most prairie dog towns were bison.


The pups that get to the surface are survivors. Some, perhaps many, pups are killed in their nursery, and the most likely suspect is an aunt, an older sister, or their maternal grandmother. John Hoogland has probably spent more time studying prairie dogs than any human alive or dead, and he reckons 20 to 25% of all pups are killed by 1 of these female relatives before they ever see the light of day. The female relatives are fingered as suspects because of a great deal of circumstantial evidence. They have the opportunity-their burrows are closest to the putative victims’ and they have the best chance to slip into the burrow while the mother is feeding in the grass. They have the means-the two long, sharp front teeth that are part of the definition of a rodent. And, Hoogland argues, they have a motive-they don’t just kill the pups, according to his dark scenario, but they also eat them, thus turning their victims’ bodies into milk for their own hungry pups.

/////////////////////////////////////////////////////////////////////////////////////bison A rattlesnake can’t hide on the putting-green surface of a prairie dog town, and it quickly finds itself fang to face with a resident prairie dog. A lone prairie dog may simply retreat, but is more likely to announce the visitor by barking (hence the name “dog”) or jump-yipping: flinging itself upright on its hind legs and yipping. Adults bark when the visitor is acutely dangerous-for example, a coyote or golden eagle-and jump-yip when it isn’t. They generally jump-yip to announce snakes. A bark usually sends other dogs scurrying for their burrows, but a jump-yip usually draws a crowd. Now it’s less clear who the hunter is. The prairie dogs fling soil in the snake’s face, turning their backs and kicking with their hind feet. They may dart to its tail, bite deeply into its flesh, then leap away out of range of its answering strike.


A big snake’s rattle is lower pitched, and a warm snake rattles faster. The bigger the snake and the warmer the snake the more dangerous the snake-and the ground squirrels were most intimidated by the playback of the large snake rattling when warm, and least intimidated by the small snake rattling when cold.


After tutoring by prairie dog parents-perhaps even before-prairie dog pups flinch at a rattlesnake’s sound. Imagine one setting off to explore the neighborhood, perhaps going down a nearby burrow and hearing from the darkness that rattling warning. Time to retreat. Yet how odd. Why would a rattlesnake-which takes such risks to get close to young prairie dogs-warn one away? Rattlesnakes bear their young alive and mothers are attentive and fiercely defensive. So it could be a mother defending her vulnerable newborns in a borrowed burrow. But sometimes the rattle is produced by a pseudo-snake, a very distant relative that has come to make the same sound: an owl. A burrowing owl, to be exact-a branch of the owl family that lives on the plains as the squirrels do, in burrows. So we call them burrowing owls, but “borrowing owls” would be a better name. They don’t dig, they just move into an available burrow and set up housekeeping. Having no sword to rattle, they just rattle. It’s as if a mouse being chased by a weasel took on the guise of a hawk.


though we knew how it sounded to us-the pulse rate is that of a warm rattlesnake and the pitch that of a big rattlesnake-we didn’t know how it sounded to the animals it must be directed at. All ground squirrels will eat eggs or baby birds, so any of them would be part of the target audience. /////////////////////////////////////////////////////////////////////////////////////bison

We were in western Montana, mountain country, where a ground squirrel related to the prairie dog lives. Likely the badger was enlarging the ground squirrel’s burrow rather than starting a hole from scratch. Still, a badger is several times the size of a squirrel and needs a hole in the ground several times as big. And yes, they can dig. They are, more or less, carnivorous digging machines. Short, powerful limbs. Long, strong claws. A wedge-shaped head. No noticeable neck. Give the above assemblage a motor and an appetite and it will feed itself, digging ground squirrels out of their burrows. Out on the Great Plains that means prairie dogs.   ? 134 ? Badgers are members of a family of small carnivores that includes mink, marten, ferrets, weasels, wolverines, otters, and skunks. Every member of the family eats meat and they all have musk glands that emit noxious odors in self-defense. Hence the family name, the Mustelidae. It’s a big, diverse, and pretty bloodthirsty family. But though badgers are from a big family, they’re not big on family. Behavioral ecology theory predicts most small carnivores will be solitary, and American badgers conform emphatically. (European badgers don’t, but that’s another genus, another diet-mostly earthworms-and another story.)


coyote may have teamed up with the digging badger and be waiting to snap up aboveground escapees.


The coyote was always the initiator, and often started with the same pitch the family dog uses to get something going-the play bow accompanied by some tail wagging and exaggerated sideways scampering. Pulls you in every time, right? It’s not surprising that the often gregarious coyote has the pitch in its repertoire-it has been using it on other coyotes since it was a pup. But it’s astonishing that the badger should respond to it.


the badger responds to the coyote. Both bounce about a bit, then, cautiously, they touch noses. After that, it seems each can safely turn its back to the other and go about its end of their joint business. While they lasted, these relationships were as transforming as falling in love. Not only did badger and coyote tolerate one another, but when they took a break from hunting they lay down together-sometimes even touching. But these were not long-term commitments. Few such partnerships lasted more than a couple of hours. Afterward, each animal went back to its solo strategy, with the highly specialized badger pursuing its one method-dig and devour.


On the desert of the southwestern United States and northern Mexico, coyotes are small and solitary. They wander widely, mostly at night, snapping up mice and moths and daintily removing the fruit from prickly pear cactus in season.


In the snows of Alberta’s Rocky Mountains coyotes may form packs, probably of relatives, and kill grown mule deer. The bigger the coyote and the more help it has, the better its chances of killing a deer several times its own size. Food packets big enough to share are big enough to be worth stealing, and a group can more effectively defend a parcel than an individual. Family packs at Jackson Hole, Wyoming, get most of their food from really big parcels-elk that die from wounds or old age every winter. The family packs defend these carcasses from other family packs. These packs are organized like wolf packs. One pair breeds and the others, mostly their adult offspring, help raise the pups. /////////////////////////////////////////////////////////////////////////////////////bison What was probably the last buffalo hide hunt in Texas, in 1879, killed only twelve buffalo.


Ferrets  A grizzly digging for a prairie dog would be visible to the naked eye a country mile away. A badger doing the same work would be in plain sight for at least 200 yards. But the badger has a slender cousin that slips into a prairie dog tunnel during the night without displacing a spoonful of earth.

/////////////////////////////////////////////////////////////////////////////////////bison this masked westerner is itself a cutthroat that invades towns on the prairie and kills and devours the residents-sometimes, in a small town, down to the last dog.


Long, low, and slender, they find prairie dog tunnels to be just their size. So they simply move into a home a dog has dug, evict or eat any occupants, and snooze away the days when most of the animals that would eat them are active, emerging mostly at night to convert the occupants of the neighboring burrows into entrees. Like other weasels, they eat both summer and winter, so a family of ferrets can make a big dent in the numbers of their immediate neighbors. When the Grand Duke Alexis safaried on the Great Plains, there were billions of prairie dogs and likely hundreds of thousands of black-footed ferrets. But the species is a victim of its own successes, combined with our excesses. Natural selection molded it, body and behavior, into a prairie dog-killing machine; but in giving the ferret that singular success, natural selection pruned away all its other options. Prairie dog towns are the only communities where it can find work, and we have poisoned and shot so many dogs, and plowed under so many dog towns, that black-tailed prairie dogs will probably soon be listed as an endangered species. The black-footed ferret has become perhaps the rarest and most endangered mammal on earth. And while bison and black-footed ferrets once lived together on most of the vast North American Great Plains, today there isn’t even an acre left where they do.


I sat with my mother’s father after her funeral. He had grown up on a ranch in Oklahoma when it was a territory and became a veterinarian, first working with livestock in South Dakota, then with wild animals for the U.S. Fish and Wildlife Service. He loved animals and he understood them. And he made me understand how my mother came to be killed by one of the family horses. “Joyce never understood horses,” he said. “She thought Smoky was her friend-would look out for her.” But Smoky had thrown himself backward while she sat in the saddle, and had driven the saddle horn into her heart. Before you try to be friends with any animal, take a close look at how it treats its other acquaintances, because chances are good that that’s how it will treat you. Few animals have much social flexibility. They assign each individual they encounter to one of a small number of categories: members of other species are predators, competitors, or neutral nonentities. Your dog may treat both you and your cat as members of its pack, but treat your neighbor as an intruding member of another pack and your neighbor’s cat as prey. The neighbor’s cat will likely treat both you and your dog as predators, and your neighbor’s dog is likely to treat you as your dog treats its master. Being a neutral nonentity has a lot to recommend it. If you avoid getting trampled in the rush to be a neutral nonentity, your problems still aren’t over. Any change in your behavior, or in the beast’s mood, can easily lead to reassignment to a more dangerous status. Stepping toward, reaching out toward, speaking to, can change you into … what? A predator to be defended against? A social upstart to be put in place? Hooves and horns are for dealing with both, and when they’re wielded effectively they can be lethal. Even if you don’t change, the animal’s mood may. Cowbirds often attend closely to grazing bison, feeding on the insects that the grazing flushes, and the grazer treats them as neutral nonentities. Yet I’ve seen an excited bull attack his cowbird contingent, lunging down and slamming a horn into the sod, vainly trying to gore them. The quicker birds easily escaped, preserving both their dignity and their proximity to their insect-flusher. People aren’t that quick.


One proud owner showing off his little herd of pet buffalo was suddenly lifted off his feet when his young bull’s horn entered his belly and found solid purchase in his rib cage. The man’s luck got better at that point. The upward thrust that gored him tossed him over a fence and at the feet of a visiting veterinarian. The vet kept him alive. A rancher in Idaho, Dick Clark, raised a bull from a calf, and even when it was full-grown it let him pet it and climb onto its back. It seemed real friendly. Then one day it killed him, mutilated his body, and drove away those who tried to remove the body from the corral.


The bull’s behavior caused that blood to be spilled, but behind that behavior lay the source of this double tragedy-the man’s belief that he and the bull were friends.


Converting a bison to a beast of burden means getting it to walk or run-things it normally does on its own initiative-on command, while wearing a harness or saddle and bridle. The bison resist, and the usual technique for overcoming that resistance is to be forceful; breaking them to harness or saddle is the usual term, and it’s a good description. Most animals can be socially dominated, at least temporarily and at some stages of their lives. That keeps them from getting maimed or murdered in a battle they can’t win. The breaker taps into this adaptation, asserts him or herself as the dominant in the relationship, and gets submission from the beast. People don’t tame bison to get beasts of burden, they tame them to prove either that they are tamable or that somebody has got the stuff to do it-in either case, for an audience.


Several times I have heard a grunt, the sound of expelled air and rapid hoof beats, and turned to find a mother buffalo charging. Apparently I had just been reclassified from neutral nonentity to predator, or from distant predator to too-close predator. Some authorities recommend “calling the buffalo’s bluff” by standing your ground, waving your arms, and shouting. Running away, they say, would encourage further pursuit. I’ve always run away. Calling an animal’s bluff works only if it is bluffing. If it’s not, then you’re not even a moving target. I have little confidence in my ability to intimidate an animal that will attack a pack of wolves or a grizzly bear. The cow has always turned away from my rapidly retreating back and returned to her calf.


If the mother chases one wolf very far, she leaves her calf exposed to the others. No profit, then, in running after a diminishing threat. Getting right back to the calf is a good rule of thumb, and mothers seem to follow it. In fact, in their everyday lives it pays bison to ignore just about anything that stays at a proper distance. The proper (neutral) distance varies from thing to thing and depends on the particular bison’s experience with it and momentary mood, so there’s no set rule. But more distance is always better


Natural selection shaped each bison, blood, bones, and behavior, to inhabit the center of our continent, dealing with the hunger of its predators and the competition of its fellows. As a wild animal it wasn’t selected to interact with us and it isn’t very flexible.


Even the domestication going on in some lines hasn’t gone very far. If we are to have a benign relationship with bison, we humans will have to do most of the adjusting. If we can appreciate what they really are, instead of what we want them to be, our future together can be safer and richer for us, and safer and more secure for them.


They used the same knowledge in other buffalo drives at other seasons-into a pit created by dissolving limestone; into a narrow arroyo, a corral the hunters had built of stone and wood; or even, in southern Colorado, into a sand dune. Their understanding showed, too, in the wolf hide hunt. Recipe for a successful hunt: dress and act like your quarry’s ancient and mortal enemy, and saunter up very close-being sure to stay in plain sight of your prey. It’s not obvious that it will work, but the man wearing the wolf pelt next to his dark skin and approaching the buffalo herd on his hands and knees knows something that isn’t obvious. He knows about wolves and buffalo.


He knows that only a few interactions between them are a headlong chase-most are a subtle dance. Buffalo and wolves saw a lot of each other and came to know each other well. Bison saw wolves too often to fling themselves into headlong flight every time one appeared. Wolves aren’t always hunting-sometimes they’re patrolling the boundaries of their territory. Sometimes they’re on a social errand. Even if they are hunting, they may not be hunting buffalo, especially if the hunt is undertaken alone. And even when they’re hunting buffalo, they may not be dangerous. And even if they are hungry, they don’t just fling themselves at the nearest buffalo. An adult cow weighs as much as ten wolves, an adult bull as much as eighteen or even twenty. They are quick, kick like a mule, and can drive a horn through another bull’s rib cage with one swing of the head. Wolves, even a pack of them, approaching a herd of bison are not likely to attack a healthy adult. They seek the weak-calves or sick or injured adults. Bulls and cows without calves have little to fear from a single wolf, and not enough reason to spend energy escaping it. So the healthy adult’s best move is to stay put, keep a casual eye on the wolf, and go on grazing, and that’s what it usually does-in that sense it “knows” the wolves; and the man on his hands and knees, now very close to the bison, understands the bison’s knowledge of wolves. That understanding lets him hide where grass too short to hide a robin stretches for miles. And so hidden, he draws his bow and kills a bison. The hunter was hidden in plain sight. And though the wolf’s skin lay over him, it wasn’t really the wolf’s skin that hid him, it was the bison’s understanding of-really, its adaptation to-the wolf. In this hunt, as in the jump, the hunter not only understands the bison’s behavior well enough to predict it, but understands it well enough to turn the prey’s strengths to weaknesses, its defenses to vulnerabilities.


sometimes, when the rivers froze, wolves came as a pack and drove the bison onto an expanse of winter ice, where their hard, smooth hooves had little more purchase than a man would find trying to walk on ball bearings. The bison were nearly defenseless, and even the strongest were vulnerable.


The people’s understanding of bison behavior was their most important tool. Their stone weapons and moccasined feet would have been useless without it. Their physical technology didn’t allow them to simply overpower bison. But about 300 years ago that suddenly changed. The plains dwellers began to ride horses.


The hunt that the horse made possible differed from the hunts that came before it in a very important way. It overpowered the bison’s defenses rather than exploiting them. Now it was the horse that the hunter needed to understand and manipulate, no longer the bison or the wolf. From above and behind the hunter’s horse’s head comes a whoop, round heels dig into its ribs, and a quirt lashes its hips. Be that horse for a minute or two, running, muzzle out, ears back as your hooves reach, strike sod, and reach again, one at a time but furiously, as you begin to gallop. Before you other runners, as large as or larger than you, are galloping on cloven hooves. They do not run from the quirt or the heels, they run for their lives and they are fast, but not as fast as you. Your ancestors are the hot-blooded horse breeds-Andalusian, Arabian, barb-spirited horses, always ready to run fast and far. Your species became swift and enduring on these same plains running for their lives, then humans took a hand and selected a line even faster. And so you gain on the running buffalo despite the weight on your back.

/////////////////////////////////////////////////////////////////////////////////////bison even a buffalo horse has its limits and there will seldom be more than three buffalo. /////////////////////////////////////////////////////////////////////////////////////bison get another arrow fitted to the bowstring, select another buffalo to kill, guide the horse to it by the pressure of his knees, shoot for the diaphragm and lungs. All the while he is keeping track of the other hunters riding in a long skirmish line, overtaking and infiltrating the running buffalo. /////////////////////////////////////////////////////////////////////////////////////bison Nothing in the bison’s history had prepared it for the buffalo rifle. Danger always came at them, growing larger in their eye or louder in their ear as it grew closer. The bullet was invisible. But what about the sound? Surely the boom of those black powder rifles filled the ear like a thunderclap. Why didn’t the herd flee from the first shot instead of grazing quietly, as they often did, while dozens fell to the rifle one by one? Perhaps because the rifle filled the ear too much like a thunderclap. Thunderclaps were common where bison evolved, /////////////////////////////////////////////////////////////////////////////////////bison That gives us a possible explanation for the boom, but leaves us with the smoke-a sudden cloud the size of a garbage can that quickly dissipated. Maybe they appeared to be dust devils. These tiny tornadoes are common on the plains. Heat sets the winds to suddenly spinning, and where they touch the earth they gather dust and dried bits of plants that are airborne for the seconds or minutes the dust devil lives;


Famine was first reported among the Comanches on the southern plains in 1800, less than 100 years after their arrival. They weren’t starving in the midst of plenty. Buffalo were sometimes scarce, for on the southern plains they were under a lot of pressure. There were many more people hunting them. They had to compete for grass with feral horses-perhaps 2 million of them. And the plains, and especially the southern plains, had drought years. Drought can reduce the primary productivity of a short-grass prairie by 90 percent, and it takes three to five years for the grass to recover. And horses brought one more change. They didn’t just increase the kill, they made it much more selective. Hunters on foot often had to take potluck so far as age or sex was concerned. But hunters on horseback could choose, and they chose cows. Cows’ meat was more edible and their hides-thinner, lighter, more pliable-were more valuable.


The effect on the bison population was devastating. Selectively hunting cows sent the population in a downward spiral. Bison cows have at most one calf per year, the first born when they are at least three years old. If the calf crop decreases but the wolf population stays the same and continues to kill the same number of calves, then the wolves will take an ever increasing percentage of each year’s calf crop. Likewise, the fewer the cows left in a population, the greater the percentage that must be taken to get an equal number of robes each year. Bulls come to predominate in the population, each eating more forage than a cow, while fewer and fewer ever contribute to reproduction.


By 1840 the harvest had risen to 100,000 robes a year. It was the first linking of steam power and bison, but not the last. The rise of steam and the decline of bison were inextricably linked-in a sense, a large part of the vast herds disappeared into the clouds of industrial steam rising in America and Europe.

Leather was in great demand just then. The industrial revolution was firing up its motive force-steam engines-in eastern North America and Europe. These industrial engines used steam to spin a wide, flat steel wheel. A long belt fitted over both the steam engine’s flat wheel and another flat wheel on the industrial machine to be powered, much like the belt with which a modern automobile engine drives its fan. Thus industrial belting was a critical link, and most industrial belts of the time were made of leather. Buffalo hides made good industrial belting.


Like wolves, wild bison still exist, but they exist as little islands in a sea of increasingly domesticated relatives-not yet cattle, but no longer wild bison. Perhaps we should call these animals that started as buffalo but will end as a kind of cattle “buffattle.” If bison domestication goes well, buffalo ranching will spread and wild buffalo will end up on islands in a sea of buffattle. We must not let them drown in that sea. It would be a terrible irony if we saved wild buffalo from the hide hunters’ Sharps rifle, then lost the species to the breeders’ bottom line. The most vivid threat today is eradication by modification.


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