Climate Change Shrink the Species

Little People: Will Climate Change Shrink the Species?

By JEFFREY KLUGER | February 24, 2012 | 

ILLUSTRATION BY DANIELLE BYERLEY / UNIVERSITY OF FLORIDA

This artist reconstruction compares Sifrhippus sandrae, right, with a modern Morgan horse that stands about 5 feet tall at the shoulder and weighs about 1,000 pounds. Sifrhippus, the earliest known horse, was the size of a small house cat (about 8.5 pounds) at the beginning of the Eocene about 56 million years ago.

If you think there are no new reasons to get freaked out by climate change, try this: There’s at least a theoretical possibility that a warmer and warmer world could lead to tinier and tinier humans. That’s the inevitable conclusion of a just-published study of Siferhippus sandae, the littlest horse that ever lived.

The Siferhippus sandae first appeared about 56 million years ago, and it was never a terribly prepossessing creature, weighing no more than 12 lbs. (5.5 kg). While it was not exactly built for steeplechase running, its skeletal architecture — not to mention its unmistakably equine face — mark it as a great-great-granddaddy of the modern horse./.../