DENVER, Aug. 7 (UPI) -- A global warming span from 53 million to 47 million years ago strongly influenced the biodiversity of western North America, geologists said.
The warming spurred a biodiversity boom of plants and animals, the researchers reported this week in the Proceedings of the National Academy of Sciences.
"Today, the middle of Wyoming is a vast desert, and a few antelope and deer are all you see," geologist Michael Woodburne, of the Museum of Northern Arizona, said.
Fifty million years ago, however, when temperatures were at their highest, that area of Wyoming was a tropical rain forest teeming with lemur-like primates, small horses, forest rodents and other mammals, Woodburne said.
"In fact, there were more species of mammals living in the western part of North America at that time than at any other time," he said.
Woodburne's research into global warming was aided by Gregg Gunnell of the University of Michigan Museum of Paleontology and Richard Stucky of the Denver Museum of Nature & Science.