A Tiny Horse That Got Even Tinier as the Planet Heated Up

by Rebecca on March 1, 2012

in Animal Stories,Animals in the News

Illustration by Danielle Byerley, Florida Museum of Natural History

Artist’s reconstruction of Sifrhippus sandrae (right) touching noses with a modern Morgan horse (left) that stands about 5 feet high at the shoulders and weighs approximately 1000 lbs.

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It happened to Sifrhippus, the first horse, 56 million years ago. Sifrhippus shrank from about 12 pounds average weight to about eight and a half pounds as the climate warmed over thousands of years, a team of researchers reported in the journal Science on Thursday.

The horse (siff-RIP-us, if you have to say the name out loud) lived in what is still horse country, in the Bighorn Basin of Wyoming, where wild mustangs roam.

Sifrhippus was not much like the mustangs or any other modern horses. It was the size of a cat, ate leaves rather than grass and counts as a horse only in scientific classification. It might have made a nice pet if anyone had been around to domesticate it, but the first hominids were a good 50 million years in the future.

Its preserved fossils, abundant in the Bighorn Basin, provide an excellent record of its size change over a 175,000-year warm period in the Earth’s history known as the Paleocene-Eocene thermal maximum, when temperatures are estimated to have risen by 9 to 18 degrees Fahrenheit at the start, and dropped again at the end.

Read more at: New York Times


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