And, of course, the last factor—and it's the one that I think is perhaps the one that breaks the back of buffalo by the middle of the 19th century—is the global market economy, and the gradual luring of Plains Indians into the global market. (We've long known that Indian hunters played a role in the beaver hunt in the Rocky Mountains in the 1820s and 1830s.) Scholars of the fur trade have known that Indian hunters were involved in providing buffalo robes. Robes were usually taken from buffalo cows, which produced the softest pelts. They were finished by Indian women, which in effect made the labor of Indian women a premium on the Plains in the 19th century. It took an Indian woman usually a week to ten days to finish out a buffalo robe. It's an enormous amount of work to do it. They were finished very soft, with the hair on one side.
They became an item in the global market economy as early as the 1820s, and we know that by the 1820s as many as 100,000 buffalo robes were arriving in New Orleans each year, in 1827, 1828, 1829. By the 1840s the market has shifted to the northern plains, the Missouri River especially, made possible by steamboat navigation on the Missouri River—the Yellowstone made it up the Missouri River in 1832–and suddenly buffalo robes began pouring down the Missouri River at a level that's been estimated at probably a hundred to a hundred and fifteen thousand robes a year during much of the late 1830s and 1840s.
At the same time, in Canada, realized that they're going to have to trade for buffalo robes, or most of the Indian trade is going to go to the Americans, and so they start buying buffalo robes in the same period. And in the middle of the 1840s something like 75,000 buffalo robes—I believe 1844 was the peak year for the Hudson's Bay Company, when 75,000 robes were traded to their posts in Canada.
What this meant was that Indian hunters, lured by the market, and what they were getting in exchange for these buffalo robes were metal wares, also guns, powder and ball to prosecute their wars. Their wars were usually with other tribes, and their wars were often over access to buffalo country. They were trading for the items of the Industrial Revolution. And the, if you happened to saturate a tribe with the items of the Industrial Revolution, the traders always had alcohol to fall back on, for which there basically was an unlimited demand. And lots of tribes were lured into alcoholic consumption because of the trade during this time.
And so, in exchange for alcohol and the goods of the Industrial Revolution, Indian hunters began hunting buffalo for the market at a rate that probably was becoming unsustainable for buffalo by about 1840 or so. The reason it was unsustainable is because Indian hunters were killing, basically—for some tribes that we have evidence for, the Southern Cheyennes, for example—roughly three times the number of animals they needed for subsistence alone, in order to provide robes to the traders.
What the traders wanted were prime robes, stripped from buffalo cows, and so Indian market hunters concentrated on cows. And of course what that meant is that you're concentrating on the gender that's capable of replicating the population. So this focus on cows for the market from the 1820s to the 1840s, I think, is really beginning to produce a serious drawdown of buffalo.