fossils Grinnell had dug up during the Marsh expedition, including miniature horses, mammoths, camels, and mastodons. These grazing animals were hunted by fierce predators, now extinct, including several species of saber-toothed tigers and the dire wolf, a larger version of its modern descendant.5
It is not clear exactly when humans first appeared on the Great Plains, though we do know that by at least 12,000 years ago, human hunters were among the predators stalking bison. We also know that around the same time, most of the large mammals of the plains became extinct. It is unknown whether they died because of human hunters, the climate change that followed the last ice age, or some combination of the two. Whatever the cause, a few resilient survivors were able to adapt to their rapidly changing world. One was mankind. Another was the modern wolf. Another was a new species of bison that zoologists would one day name Bison bison—the modern buffalo. Bison bison had at least one advantage that helped it survive against primitive human hunters. More ancient species of buffalo, with their gigantic horns, defended themselves by standing and fighting. Armed with a long spear, a hunter could defeat this strategy. Bison bison had a different defense, one more difficult for man to overcome. Instead of fighting, Bison bison ran away.6
The modern buffalo, winner of a brutal contest that wiped out hundreds of other species, is a survivor of stunning physical attributes. Though its ultimate defense is to run away, the buffalo projects a physical presence that is intimidating to most predators. Bulls can weigh more than a ton, with thickly furred heads and leg pantaloons that make them look larger still. Both male and female buffalo have hooked horns, far smaller than those of their ancient ancestors but still plenty potent. With powerful neck muscles to support their massive heads, a buffalo can throw a wolf thirty feet. In breeding season, a male buffalo can kill a rival with one goring stab of his horns. Indeed about 5 percent of mature bulls die each year from wounds they receive in battle with their peers.7
Having survived both the Ice Age and its aftermath, buffalo can thrive in a remarkable range of climates, from 110 degrees Fahrenheit on the deserts of Mexico (or Nebraska) to –50 degrees Fahrenheit on the windswept plains of Canada. A buffalo’s thick coat has ten times more hairs per square inch than the hide of a domestic cow. Yet in the summer, the buffalo sheds down to a thin coat as sleek as a lamb, newly shorn for the county fair.8
The buffalo and its relatives (including deer, elk, antelope, and the domestic cow) are ruminants, with digestive systems well attuned to subsist on the grasses of the Great Plains. Humans can’t eat grass because we can’t digest cellulose. Buffalo can because the first chamber of their alimentary canal—the rumen—is a sort of vat in which colonies of bacteria help to break down cellulose into usable carbohydrates. To further promote the process, ruminants chew their food twice: once before swallowing and a second time after fist-sized portions—the cud—are regurgitated and then chewed again.9
The buffalo’s gigantic head serves a purpose beyond intimidation. In the winter, it becomes a powerful plow to push snow away from buried grass. Cattle, by contrast, have no such ability to dig for food. If not fed by ranchers during an extended period of heavy snow, cattle die.
Buffalo reproduce in prodigious numbers, at least by comparison with other large mammals. Buffalo cows drop their first calf at age 3, and in domesticated herds they have been bred beyond age 30. If a herd is well nourished, 85 to 90 percent of mature cows become pregnant and give birth each year. Farmers of modern dairy cattle, by contrast, using high-tech, artificial insemination, might achieve a birth rate of only 50 percent.10
Buffalo calves are born ready to run. Within two minutes of birth, a buffalo calf tries to raise itself. Within seven minutes, it is standing. Within an hour, a buffalo calf can run after the herd.11 In a domesticated herd, a newborn calf was once herded sixty-six miles, through deep snow, in its first two days of life, with no apparent ill effects.12 Such early skill and endurance is vital, since running—and the herd itself—are a buffalo’s primary defenses.
Despite the buffalo’s plodding, cumbersome appearance, it is shockingly fast and agile. An adult buffalo is as fleet as some racehorses in the quarter mile, but unlike a horse, a frightened buffalo can run across the prairie for miles without stopping. A nineteenth-century scientific expedition once required a relay of three fresh horses to run down a buffalo cow, covering twenty-five miles in the chase. As for agility, a biologist at the National Bison Range in Montana once observed a 2,000-pound bull leap up a six-foot embankment from a standing start!13
The buffalo’s skill at running away is enhanced by the collective power of the herd to tell it when to run away. The phrase “herd mentality” may carry a pejorative connotation for humans, but not so the buffalo: Hundreds (or thousands) of pairs of eyes, scanning the broad horizon. Hundreds of noses, sniffing for foreign scent. And then, at the first sign of danger, a powerful instinct to follow after the fleet, fleeing mass. When pursued, the herd protects its members through sheer numbers. A buffalo doesn’t need to be faster than predators; it just needs to be faster than a few of the other buffalo.
Against the buffalo herd, even a predator as effective as the wolf represents little risk except to the young, the old, and the injured or sick.14 Healthy adult buffalo (not including cows with calves) pay little attention to wolves. Indeed Indian hunters sometimes cloaked themselves in wolf skins in order to crawl within easy shooting distance. The power of the herd (especially its size) even insulated the buffalo against its most effective predator—humans.
The question of how many buffalo walked the North American continent before the arrival of Europeans is a source of considerable disagreement. Sixty million has been a common number cited, and some estimates are as high as 100 million. The late Dale Lott, a biologist at the University of California, Davis, and a leading expert on the buffalo, studied these higher numbers and made a persuasive case as to why the number of 30 million—though still an educated guess—is the better estimate based on the continent’s carrying capacity.15 Still, 30 million is an enormous number.
Equally impressive is the range that these buffalo covered. The fact that buffalo inhabited the Great Plains from Mexico to Canada is commonly known. Less well known is the fact that at the time the Pilgrims landed at Plymouth Rock, some 2 million to 4 million buffalo lived east of the Mississippi—in every future state but the northeast cluster of Maine, Vermont, New Hampshire, Connecticut, and Rhode Island.16
The buffalo, in short, was a remarkable survivor. It had prevailed through prehistoric episodes that forced hundreds of other mammals into extinction. It thrived in climates ranging from subtropic Mexico to subarctic Canada. It could defend itself against the relentless attacks of the most deadly predators in its environment, including packs of wolves and prehistoric humans. The buffalo, it seemed, was perfect.
BY JULY OF 1872, GEORGE BIRD GRINNELL AND THREE COMPANIONS were crossing into northern Kansas on horseback, hurrying to catch up with a tribe of 4,000 Pawnee Indians. Relations between whites and Pawnees were peaceful, in part because the Pawnee ceded their traditional Kansas and Nebraska lands early. The Pawnee were enemies of the Sioux and the Cheyenne and often served as guides to U.S. Army soldiers during the wars with those tribes.17
In 1872, the Pawnee were confined to a small reservation along Nebraska’s Loup River. Twice a year, though, the army allowed the tribe to travel south to hunt buffalo in their historic Kansas hunting grounds. “[F]or a little while,” wrote Grinnell, “they returned to the old free life of earlier years, when the land had been all their own, and they had wandered at will over the broad expanse of the rolling prairie.”18 The tribe left the reservation two weeks before Grinnell arrived in Nebraska, so now Grinnell and his companions hurried to catch up. Their guide was Lute North, who, like his brother, was an experienced young army officer. Lute spoke fluent Pawnee and was known and respected by the tribe.
After a few days
