A photograph from the 1870’s showing tens of thousands of bison skulls. They were mass slaughtered by the U.S. Army to make room for cattle and force Native American tribes into starvation.
Mass slaughter of buffalo and bison took place in Canadian territory as well, and was part of a deliberate campaign to break Indigenous resistance to (further) settler incursions onto Native land and the railroad. The removal of the buffalo also meant that when it came time to sign treaties, the Canadian government could more or less set any terms it saw fit and Indigenous leaders basically had to comply with them or their people would freeze and starve (that’s if gov officials even bothered to translate the actual terms of the treaty at all).
The “disappearance” of the buffalo is narrativized as part of a larger myth surrounding the “disappearing Indian” whose absence clears the land for the incoming white pioneers to take their place. The murder, destruction, slaughter of bison and buffalo was a tactic essential to the genocidal colonial project.