for National Geographic News
An ancient period of global warming spurred the world's first primates to spread from Asia to North America, new research shows.
The animals may have taken as little as 20,000 years to disperse across the Northern Hemisphere from the moment they first appeared.
The findings were reported by scientists studying the fossils of animals called Teilhardina, which have been found in China, Belgium, and the western United States.
Teilhardina were tiny primates about the size of chipmunks that jumped through the forest from tree to tree, says paleontologist Philip Gingerich.
Gingerich, from the University of Michigan, is a co-author of the new study, which appears in the July 25 issue of the Proceedings of the National Academy of Sciences.
(He is also a member of the National Geographic Society's Committee for Research and Exploration. National Geographic News is a division of the National Geographic Society.)
Gingerich's team concludes that the tiny primates first appeared in China at the beginning of an ancient warming period that began 55 million years ago.
The animals appeared in Europe slightly later and then made their way to North America 20,000 years into the warming event.
"So you have a suggestion that it's appearing earlier in China than in Europe, and earlier in Europe than in North America," Gingerich said.
In addition, he says, the Chinese animals appear to be more primitive than the European ones, which in turn appear more primitive than North American specimens.
This indicates that Teilhardina migrated west from China to Europe and then to North America, covering 12,000 miles (20,000 kilometers) in 20,000 years.
That, Gingerich said, represents "very rapid dispersal," occurring at the same pace at which animals move into new territories today.
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