Horses evolved in North America and later crossed into Asia via the Bering landbridge. When did they do that?
Humans crossed the other way some 12,000 or more years ago. Did any other large animal cross the landbridge either way?
I am unaware of any species which crossed Beringia in the terminal pleistocene.
A land bridge has connected North America and Eurasia intermittently since the Cretaceous. Tyrannosaurs, for example, seem to have evolved in NA and later appeared in Asia.
I’m not going to try to outline all the comings and goings over tens of millions of years. However, deer, cattle (bison, mountain goats, sheep), elephants (mastodonts, gomphotheres, and later mammoths), certain rodents (lemmings, e.g.), and lions crossed from Eurasia to North America. Horses, camels, and probably cheetahs evolved in NA and crossed to Eurasia.
Yankee camels? coool.
One of the most far-reaching transfers across the Bering land bridge was the Myomorpha interchange – mouse-like rodents going both ways.
The house mouse and the common rat are both Old World mice – Family Muridae, which invaded the New World either by the landbridge or with early colonists. Native rats and mice such as the muskrat and the deer mouse are Cricetids, New World mice – as, interestingly, are the hamsters of the Middle East and the SDMB server.
Also quite interesting is the opening of the Central American landbridge, which of course still exists, in Pliocene-Pleistocene times, and the creatures that went both ways on that.
Wait a minute. Wasn’t North America still connected to Europe during the Cretaceous?
Anyway, I was more interested in those that crossed during the ice ages of the last few million years. But then I had the idea that after the split from Europe, there wasn’t any landbridge until the recent ice ages. Apparently, this was a mistaken idea. Were all these land bridges caused by ice ages?