American sugar refineries used charcoal made from bison bones to remove color from sugar syrup. After the great slaughter, there was another business waiting on the Plains. People gathered the skeletons, hauled them to railroad sidings and sold them by the ton. Factories farther east wanted the bones for fertilizer and animal charcoal. That famous photograph of a mountain of bison skulls was taken at Michigan Carbon Works near Detroit in 1892. You’re looking at a factory’s supply of raw material. The company had been founded in 1873 to turn bones into charcoal for sugar refining. Railroads made the trade practical: freight cars carrying goods west could return east loaded with bones. Some homesteaders paid for provisions by gathering skeletons before they had a crop to sell. Native people and Métis families also entered the trade as the disappearance of the herds destroyed their livelihoods. At Devils Lake in 1885, buyers weighed loaded wagons, sent them to unload beside the tracks, then weighed the empty wagons and paid the difference. Boxcars took the bones to Chicago, Detroit and St. Louis. The business followed the expanding railroad into country where bones could still be found. Eventually, dealers had a supply problem. They were running out of skeletons.