Why did buffalo disappear?

The vast herds of the American bison were deliberately hunted to almost extinction by the white settlers, the army, and was encouraged to do so by the American Government. It was a policy to force the native tribes onto indian reservations, or starve. With the arrival of the railway, it was not unusual for some passengers to shoot bison from the moving train. The carcases were left to rot. Nowadays,, the bison is protected and is gaining in numbers.