If there is one animal that has become a beloved Australian icon it is the Koala (Phascolarctos cinereus). Widely perceived as cute and cuddly this arboreal marsupial feeds a few hours a day on Eucalyptus leaves. As this diet hardly contains any nutrients and calories koalas spend most of the time sleeping in a tree, and as nineteenth century British naturalist John Gould observed ‘it is so slothful that it is very difficult to arouse and make it quit its resting place’.
Large numbers of koalas have been hunted for its fur and skins in the late 19th and 20th century. Regarding the millions of skins exported Koalas once were much more abundant than they are today. However, clearing, fragmentation and degradation of natural habitat, infections with Chlamydia, bush fires and drought are the main causes of population declines or collapses since the ban on the fur trade.
The natural range of Koalas currently stretches from the north-east Queensland to the south-east corner of South Australia, a distribution thought to be similar to the one prior to European settlement in Australia. Although fossil Koalas were recovered from several Plio-Pleistocene deposits in Western Australia – notably Mammoth Cave and Delvil’s Lair in the south-west and Koala Cave in Yanchep National Park – Koalas don’t occur naturally in this state. A 1930’s translocation of a Victorian population initially brought the Koala back to Yanchep National Park but death and diseases forced conservationists to bring in new colonies twice. The current colony hails from Kangaroo Island, South Australia, brought in to replace individuals rendered infertile by Chlamydia in the 1980’s. They nowadays are healthy and happily feeding on the ample trees within their sanctuary.