Koala. Its name comes from an ancient Aboriginal word meaning "no drink" because it receives over 90% of its hydration from the Eucalyptus (Gum Tree) leaves it eats. Its one of only 3 mammals which can survive on a diet of eucalyptus leaves. Koalas today are found in Queensland, New South Wales, Victoria and South Australia. Koalas live in societies, just like humans, so they need to be able to come into contact with other koalas. It is because of this they need to have areas of suitable eucalypt forests.