Although the herds stood “in such immense numbers as to defy computation,” Ernest Thompson Seton, the Canadian naturalist, had a try at computing their overall numbers. In 1906 he estimated that, since 24,000,000 cattle and horses then lived on 750,000 acres of fenced plains (about half the plains available to buffalo), surely 40,000,000 buffalo could have lived here. He estimated that another 30,000,000 could have lived on the 500,000 acres of the prairies—they would support that many buffalo per acre. And he estimated that only 5,000,000 animals could have lived in the 1,000,000 square miles of forests of the East. This gave him a total of about 75,000,000 buffalo living in North America in primitive times; he conservatively lowered this to 50,000,000 or 60,000,000. As a population that expanded, he argued, at about five per cent a year until Columbus arrived, they might have come, Seton thought, to the point of overcrowding. Others believe that their enormous natural losses kept them from outgrowing their food supply. And Tom McHugh, a biologist, disagrees with Seton’s figures. Using the “carrying capacity” of the 1,250,000 square miles of grassland available to buffalo as 25 acres per buffalo, he arrives at an estimate of 32,000,000 here and 2,000,000 living in bordering areas. This seems the best estimate yet.

When the Spaniards explored north of the Rio Grande in the middle of the sixteenth century, they found buffalo. When, soon after, other Spaniards landed on the Florida peninsula and moved inland, they came upon some buffalo. When still other Spaniards came to the mouth of the Mississippi and the coast of Texas, they too found buffalo. In fact, the only early Spaniards who saw and ate no buffalo were those who settled on the Pacific coast of California: buffalo of the high plains had been turned back by the barren Sierra Mountains and Mojave Desert, their numbers had been depleted by intensive hunting, and many, due to “late” arrival on the plains, simply had not had time to expand their range that far west.

The Dutch found buffalo along the Niagara; the Scots found them along the Cumberland. Spanish de Soto heard of them being in Georgia country and French La Salle noted them along the Mississippi. Americans Lewis and Clark found them all along the Missouri, but not at all along the Columbia—nor were many there.

Buffalo filled the continent from the Great Slave Lake south to the Rio Grande and, in scatterings, a little below it. Perhaps in Mexico they had made it to the Pacific, going through Sinaloa, and perhaps a few once had wandered all the way to Nicaragua. On the Pacific side of the Rockies they fed along the dark’s Fork of the Columbia, the Bitterroot, and the Flathead, ranging as far west as the Pend Oreille region, and on into eastern Washington until the peoples there acquired the horse. Then hunting held them back and eventually destroyed them. Seldom did food scarcity or unsuitable terrain stop them (it took a formidable barrier to prevent buffalo from moving where they pleased). Buffalo found easy access to the headwaters of the Columbia from the Missouri headwaters up Divide Creek and down Silver Bow Creek over an almost prairie-like Continental Divide. Thus they should have filled the Oregon and Washington plains between the Rockies and Cascades, yet only a few scattered skeletons have been found in eastern Washington and fewer still in southern Oregon and northeast California. Herds did graze along the Pacificbound Salmon River and part way along the upper Snake and Humboldt rivers, having crossed the Divide on other easy passes—but perhaps only when chased across by the white man’s incursions.

Buffalo filled the country from the Rocky Mountains to just east of the Mississippi, and lived in fewer numbers from there almost to the Atlantic Ocean. They may have arrived in this country only a few hundred years before the first white man: the mound builders knew no buffalo, and the buffalo bones deposited in Big Bone Lick, Kentucky, indicate recent arrival. Perhaps they only crossed the Mississippi after A.D. 1000. Possibly they felt less attracted to the country east of the Mississippi because, like cattle, they need one-seventh of their diet to be protein, which only the prairie and high-plains grasses provided—1,250,000 square miles of it.

Buffalo fecundity plus a long breeding life may have made for buffalo dominance through numbers. Almost every cow on the continent dropped a calf each year—although cows sucking calves sometimes tended to miss pregnancy. (Today in protected herds the fertility rate approaches 90 per cent.) Perhaps 15,000,000 new buffalo arrived each year in the days before the white man.

Buffalo live twenty-five to forty years in captive herds. Wild buffalo undoubtedly died a little earlier, the victims of wolf attack when weak, but the species tends toward longevity; one yarn spinner said he’d seen them so old their horns “had decayed and dropped off.”