TIME

First Mammals

≈ 225–200 million years ago

A museum model of Megazostrodon, a small, shrew-like early mammal with grey fur, a long tail and a pointed snout, standing on a rock against a rust-red wall.

Earth & LifeFirst Mammals

Small, shrew-sized beginnings.

The first mammals appeared in the Late Triassic as small animals that evolved from cynodonts and probably hunted insects at night.

Where a mammal begins is a matter of definition. Megazostrodon, shown here, lived about 200 million years ago.

225–200 million years ago, placed on the scale of its era on a line leading toward now.

Era
Earth & Life
Period
≈ 225–200 million years ago
Edition
1/1
Status
Not Released
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Background artwork

Cinematic background showing a small early mammal at night among the dinosaurs. An illustration generated with an AI image tool for TIME. It is an artistic depiction, not a photograph or a record of the moment. Colours and surroundings are imagined.