Quetzalcoatlus

(ket-zal-co-AT-lus) Size: 17 feet long
Flying reptiles once soared through the skies, and that would have been quite a sight. This guy had the wingspan of a small airplane!

Proailurus

(PRO-ay-LURE-us) Size: 3 feet long
Not much larger than your housecat, this feline’s name means “first cat.” All cats—lions, tigers, and your pet—came from a cat like this.

Mesohippus

(meh-so-HIP-us) Size: 2 feet tall
A horse is a horse, of course. But the grandpa of all horses and zebras was smaller (about the size of a dog). And it had three toes—not just one big hoof.

Hesperocyon

(hes-per-OH-sigh-on) Size: 2 ½ feet long
If you saw Hesperocyon, you’d think it was a strange dog—and that’s exactly right. Today’s pet dogs don’t have its flexible body and long tail.

Theosodon

(thee-OS-oh-don) Size: 6 feet long
Although theosodons looked like camels or llamas, they belonged to a different kind. They were part of the only known family of animals with both a long neck and trunk-like nose.

Anisodon

(An-EES-uh-don) Size: 8 ½ feet tall
This giant walked on its knuckles like a gorilla but had a head like a horse. It probably clawed and ate leaves like a sloth. What a unique and wonderful mix.