Because of their low quality diet, koalas conserve energy by their behavior. For breeding males the home range will overlap those of females as well as subadult and non-breeding males. These calls advertise an individual's presence and warn off other males. The only vocalization generally heard from females and subadult males is a harsh wailing distress call given when harrassed by adult males. During mating the male will grasp the back of the female's neck with his teeth.
Koalas are mainly nocturnal and completely arboreal.
The koala is primarily a solitary animal, although sometimes it lives in small harems led by a single male. Habitat Koalas are arboreal, remaining mostly in the branches of the eucalyptus trees, where they are able to feed and stay out of reach of their predators. The koala is confined to eucalyptus forests below 600 m. In the early 20th century the koala was hunted extensively for its warm, thick coat. Koalas were nearly exterminated at the turn of the century because they were hunted for their fur, and because their environments were destroyed by fires caused by humans.