The Koala Phascolarctos cinereus


The Koala is probably the best known of all living marsupials. The word ‘koala’ appears to have been derived from a name used by the Aboriginal people of New South Wales, although this is complicated by dialects and variations. Although they are not related to true, placental bears, they are often called ‘koala bears’. Koalas are stocky, lack a tail, have relatively long legs and spend most of their time sitting regally in the fork of a tree. A koala has a face rather than a muzzle and eyes that are directed frontwards. All these features evoke human empathy.

Photo of a Koala

Photographer / Source: Gary Lewis

Where do they occur?

The fossil history of koalas spans a period of 15 million years, and a change in Australia’s vegetation. The clearing of forests has led to a reduction in their range to the east coast, and today they occur from the Atherton Tablelands south to Victoria and south-eastern South Australia. Koalas in the south are larger than in the north.

What do they feed on?

Koalas feed almost entirely on the foliage of eucalypts. They have particular food preferences depending on the region they inhabit. In the south they prefer Manna Gum, Swamp Gum and Blue Gum, while Red Gums, Tallowwood, and Grey Gum are favoured in the north. Eucalypt leaves have poor nutrient value, but a koala’s anatomy, physiology and behaviour is adapted to this. Foremost is their low energy requirement.

What is their breeding cycle?

Females start breeding when they reach two years of age and if healthy they can continue to reproduce until they are more than 14 years of age. Their longevity is about 18 years. Following summer mating, a single young (rarely twins) is born after a 35 day gestation period, climbs into the backwardly pointing pouch and attaches to a teat where it remains for about six months. It leaves the pouch and stays with the mother until about 12 months old when it is weaned and becomes independent.

Do they suffer from any diseases?

Koalas suffer from diseases of the eye and reproductive tract. Chlamydia is the main problem of the latter.

What is the most satisfactory management strategy?

Koalas have no natural predators – the preservation of large tracts of suitable land, and the introduction of habitat corridors is now the most important management goal.

Photo of a Koala

Photographer / Source: Gary Lewis

Further Reading

Lee, A. and Martin, R. (1988). The Koala: A Natural History. New South Wales University Press, Kensington NSW.

Martin, R. and Handasyde, K. (1999) 2nd Ed. The Koala: Natural History, Conservation and Management. UNSW Press, Sydney.

Menkhorst, P. and Knight, F. (2001). A field guide to the mammals of Australia. Melbourne: Oxford University Press.

Menkhorst, P. W. (Ed.) (1995). Mammals of Victoria. Oxford University Press. Melbourne

Strahan, R. (Ed.) (1995). The Mammals of Australia. Reed Books, Chatsworth, N.S.W.

Comments (2)

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Mason McClaugherty 28 April, 2010 04:18
What are some good resources for finding the anatomy of the koala?
Discovery Centre 2 May, 2010 10:49

Hi Mason, the Australian Koala Foundation has a huge list of resources for finding out more about the anatomy, physiology and biochemistry  of koalas. We also have a number of books in the Discovery Centre Library that may be useful for your research. 

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