The first horse on Earth was no bigger than a lamb: Meet Eohippus, the 55 million-year-old tiny ancestor of every modern horse

The first horse on Earth, Eohippus, lived 55 million years ago and was no bigger than a lamb. This tiny ancestor had four toes on its front feet and lived in dense forests. Researchers said, "The Eohippus might have been striped, making it camouflaged against the forest light during the Eocene period."