A newborn koala is about the size of a gummy bear. As soon as it's born, it crawls into its mother's pouch, where it stays for about six months, nursing and growing.

Sharp claws and two thumbs on each hand make racing up a 15-story-tall tree easy for a koala.

Koalas can't run very fast or for very long, so they are most vulnerable on the ground.

Photograph of a koala walking by Kennan Ward
Photograph of a koala eating by Tom Brakefield/Corbis