Cat Sized Horses Trotted the Earth 50 Million Years Ago

An artist's reconstruction shows Sifrhippus sandrae touching noses with a modern Morgan horse. (Danielle Byerley, Florida Museum of Natural History)

 

More than 50 million years ago, the Earth was a hotter place than it is today and horses the size of pet cats roamed the forests of North America, United States scientists say. 

These earliest known horses, known as Sifrhippus, actually got smaller over tens of thousands of years in order to adapt to the higher temperatures of a period when methane emissions spiked, possibly due to major volcanic eruptions.

The research could have implications for how the planet's modern animals may adapt to a warming planet due to climate change and higher carbon emissions, scientists said.

 

Researchers made the discovery after analysing horse tooth fossils uncovered in the western US state of Wyoming that showed the older ones were larger, and that the species had shrunk over time.

Many animals became extinct during this 175,000-year period, known as the Paleocene-Eocene Thermal Maximum, some 56 million years ago.

Others got smaller in order to survive with limited resources.

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