Koala

The koala lives almost exclusively in the top braches of eucalyptus trees. Its strong legs and sharp claws help it grip the trunks. A nocturnal animal, it feeds at night on young shoots and leaves, and spends its day sleeping curled up in a fork of the tree.

Koalas use a range of sounds to communicate with one another over relatively large distances. There is a deep grunting bellow which the male uses to signify its social and physical position. Males save fighting energy by bellowing their dominance and they also bellow to allow other animals to accurately locate the position of the caller. Females do not bellow as often as males, but their calls too are used to express aggression as well as being part of sexual behaviour, often giving the impression of fighting. Mothers and babies make soft clicking, squeaking sounds and gentle humming or murmering sounds to one another, as well as gentle grunts to signal displeasure or annoyance. All koalas share one common call which is elicited by fear. It is a sickening cry like a baby screaming and is made by animals under stress. It is often accompanied by shaking. Koalas also communicate by marking their trees with their scent.

Koalas mate between December and March. A single baby is born 35 days later. It is blind, hairless, and only 3/4 inch long. By instinct, it drags itself into its mother's pouch, which opens to the rear rather than to the front as with most other marsupials.

During the course of its evolution, the koala has developed special cheek pouches that store food and a digestive system to handle a diet consisting entirely of eucalyptus leaves. Of the more than 100 species of eucalyptus tree that grow in Australia, the koala feeds on only twelve.