How much of an effect would domestic reindeer have on North America if they were domesticated 4000 years ago?
They're herd animals that can live during mating season comfortably in the thousands, and in winter in herds of hundreds. They provide milk and meat. They can be ridden although they're not much for fighting, more like riding a donkey from what I understand. They can pull sleds so could pull a wagon as well, this also means they could potentially pull a plow.
Also Caribou a close relative live as far south as Yellowstone Park and further south before they were hunted out. So even without breeding a more heat resistant breed, they could cover a huge area.
Most timelines dealing with domestic large animals have horses, bison, dolphins or llama's, I'm curious what people think would occur with reindeer, a good potential domesticate.