アメリカ自然史博物館のインスタグラム(amnh) - 8月7日 22時17分

Fifty-five million years ago, the earliest known horses evolved on Earth. They were dog-sized at the time and remained small forest browsers for more than half their history. As climate conditions changed some 20 million years ago, grasslands expanded and divergent equine species rapidly evolved. Some horses became larger and developed grazing diets. This was the familial line that led to modern horses. For around 5,000 years, humans have domesticated horses—and altered their biology through a process known as artificial selection. As we created dozens of breeds, we also made horses faster, stronger, bigger (or, in the case of the show pony, smaller.) We’ve copiously documented their pedigrees, and in the 18th century, European “studbooks” emerged to track horse lineage and inherited traits. Those old records, along with modern DNA sequencing, now help biologists understand horses’ origins. #horse #horses #amnh #naturalhistory #fossil #fossils

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