Warm Up the Planet, Shrink Down the Species

9/13/2012 10:37:41 AM

Humans may be getting taller, but what would happen if we started shrinking instead? This is true for a certain horse called a sifrhippus sandrea.

This horse is one of the earliest-known North American horse relatives. It lived during the Eocene epoch, some 55.6 million years ago. It was also one of the smallest.

"Fossils found recently show that when the Earth warmed up dramatically 55 million years ago, the horse, already small, got even smaller," said Mark Fischetti, an editor for Scientific American. "When scientists raised fish in a lab in water that's warmer than natural, the mature fish end up smaller. The thinking is that smaller animals shed heat more easily."

The question is this: will humans begin to get smaller? The short answer is yes. Research has shown it's happening with some birds. As for humans, we may not shrink, just get taller more slowly.