They weren't naturally, the US state nearly exterminated the species as a tool of genocide against multiple Native American nations.

I'm not American either, but have heard of the near bison extinction. They made literal mountains of nothing but bison skulls.

They skinned them and left their meat and bones to rot all over the prairie.

It's hard to imagine it if you haven't seen the pictures. Even then, it's impossible.

It's crazy to think about. Especially because it's such a cool and unique animal. I'm just happy that bison still exist. I hope their population keeps growing even though they will never be as many as they were.