Koalas (Phascolarctos cinereus) are placed in their own family, which shows how different they are from other marsupials. These animals live practically their whole lives in stands of eucalyptus trees that form the core of their territories. Eucalyptus leaves are by far the most important food for koalas. The animals even smell of eucalyptus oil. A problem with eucalyptus leaves is that they are very fibrous and difficult to digest, so koalas have cheek pouches and long intestines, and occasionally eat soil or gravel. All these traits are adaptations to help them break down the tough eucalyptus leaves.

Koalas are very solitary animals and, although the territories of males and females overlap, males will not tolerate intruders of the same sex. Resident koalas usually attack intruders savagely. Males mark out their territories with strong-smelling scent, and make loud calls to warn off other males.

During the breeding season, males try to guard as many female territories as they can. The single young or joey stays in its mother's pouch for seven months, then rides on its mother's back until the next season's joey matures. Koalas used to be very common in south-eastern Australia, but a mixture of hunting for fur in the early 20th century, habitat loss and severe forest fires have reduced their numbers.


ARKive photos and videos of the koala