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The Koala
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The Koala
A Unique Marsupial from the Australian Continent
Apr 20, 2009 © Harry P. Schlanger
The koala is Australia’s best-known marsupial, meaning that the animal has a pouch. Koalas grow
to a length of 60-85cm, weighing 8-13 kg and may live 10-12 years in the wild.
Koalas live in the wild only in Australia. They are an easily recognizable species and they have become
a symbol of what is uniquely Australian.
The koala is sometimes erroneously referred to as "koala bear" due to its cuteness and resemblance to a
bear. However, the koala is certainly not a bear, nor is it related to bears. It is a very unique animal
- a marsupial with its own genus and family.
Appearance
The koala has the well known furry appearance but in particular it has:
- A stout body with relatively long arms and large paws
- Large round head with fluffy ears
- Forward facing eyes and a relatively high forehead
- Upright posture
- A pouch for rearing its young at the front
Wombats are the closest relatives to koalas. Both animals have backward-opening pouches.
Koalas rub their chest to mark their territory. They are docile animals, except when teased or frightened.
Figure 1. Koala Distribution
Koala Distribution in Australia
Fossil koalas may be found in Western Australia and Northern Territory, pointing to the
origin of koalas
that have been around for millions of years. The koala’s current
distribution is confined mostly to Victoria, New South Wales and Queensland, with a small
pocket in South Australia (Fig. 1).
Koalas Live in Trees
Koalas spend most of their life in trees. They have long arms with powerful claws that easily wrap
around the tree branches to give it a firm grip. They sleep most of the day, usually in the fork of a
tree.
Koalas are solitary animals - only rarely are two animals found in the same tree, except during mating
or when a female is carrying a young koala.
Koalas do not use nests or tree hollows for shelter but they have an extremely well insulated coat.
Koalas are agile climbers but because eucalypt woodlands have an open canopy (i.e. a sparse blanket of
tree foliage), they often descend to the ground to move from tree to tree, but they are clumsy on the
ground.
Rearing Young Koalas
In a habitat of good quality, females produce each year one young koala.
Mating occurs
in early summer. After one-month gestation period, the young koala is born and finds its way to the
mother’s pouch, where it attaches itself to a teat. The mother produces milk until the young koala is
finally weaned in late spring.
The young koala first pokes its head out of the pouch towards the end
of winter. It starts to nibble the leaves its mother is feeding on, and this is how it learns which
eucalypt leaves are best. Because of the absence of a den, a young animal is carried on its mother's
back until it grows to about 2kg in weight.
Koala Diet - Fussy Eaters
Koalas live entirely on a highly specialized diet of eucalypt leaves wherever eucalypts grow in
relatively undisturbed dry forests and woodlands. Only about 35 of Australia’s 600 eucalypt species
produce first-choice koala foliage.
Koala will starve rather than eat eucalypt leaves that are too high in tannins or essential oils,
which are part of the tree’s defence against being eaten by insects – and koalas. In some cases, they
do eat pine needled from pine plantations, but only for short periods as they pass through the area.
Koalas Population Under Stress
Clearing the koala’s habitat for farming, the
koala fur trade, forestry and urban sprawl has reduced the animal's
distribution to a small fraction of what it was 200 years ago. As a result of quality habitat loss,
the prevalence of Chamydia infections, causing infertility in females, is believed to be the main
threat to survival of koalas. The wellbeing of wild koalas depends on conservation of the remaining
habitat and restoration of damaged habitats, rather than the development of vaccines.
Bushfires and droughts also affect the koala's habitat and food supply and can also threaten the
koala's survival.
References:
- "Encyclopedia of Australian Wild Life", Edited by Louise Edgerton. Reader's Digest (Australia),
Ultimo, NSW. 1998.
The copyright of the article The Koala: A Unique Marsupial from the Australian Continent is owned
by Harry P. Schlanger. Permission to republish in print or online must be granted by the author in writing.
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