About this publication
Koala
September 2002
Is the koala a bear?
Despite being called 'koala bears' for many years, koalas are actually marsupials. Bears give birth to well-developed young. Newborn koalas, however, are tiny enough to fit on your thumbnail. They are raised in their mother's pouch.
The closest relative of the koala is the wombat - both animals have pouches which open towards the rear. This is fine for the wombat, but koalas need strong muscles ringing the pouch to keep their young from falling out.
Where do they live?
Koalas are found between south-eastern South Australia and Queensland, but only where enough suitable trees have been left. The largest koalas weigh over 10 kilograms and are found in Victoria, while the smallest live in North Queensland and weigh only 5.5 kilograms. Koalas live for between 10 and 20 years.
How do they get about?
With huge claws and strong muscles, koalas are able to hold on tightly to trees. They have two thumbs and three fingers on each front paw, which makes their grip more even on each side of a branch. They also have a clawless big toe on their hind legs, which allows them to grip with their hind feet as well. Two of their hind toes joined together form a handy two-toothed comb, used for grooming fur and removing ticks.
What do they eat?
A koala eats about half a kilogram of leaves each day. Koalas are fussy eaters, choosing most of their food from a few varieties of eucalypt. Around Sydney, red gums and mahoganies are their most favoured trees. In northern areas of the State, tallowwood and forest red gum are important, manna gum tops the bill in the south, and in the west koalas prefer river red gum and ribbon gum. They use a variety of other trees for shelter during the day and in heatwaves or storms, including paperbark, she-oak, brush box and acacia trees.
Gum leaves are not the easiest things to digest - they are tough and contain oils which can be poisonous. To cope with such an unusual diet, koalas have a long, thin tube like an appendix branching out from their intestines. This tube grows to a length of two metres. It probably helps with digestion, although its exact function remains a mystery.
As their food contains little energy, koalas conserve energy by sleeping for most of the day and looking for food in the evening.
Growing up
Female koalas can breed from about two years of age. A newborn koala is tiny, blind and hairless, and is born about two months after mating. Dragging itself into its mother's pouch, it attaches itself to one of her two teats. By about seven months, the baby has outgrown the pouch. It rides on its mother's back, or rests against her chest as she drowses in the fork of a tree. During this time, the young one samples gum leaves.
When the young koala is about one year old, its mother is able to mate again. This usually happens between September and January, when the trees ring with a wide range of mating noises. Koala mating songs range from the pig-like grunts and growls of the males, to the high pitched trembling sounds of the females. Often, young male koalas will be driven off by older males. To survive, they must find a suitable area which is not already occupied by other dominant male koalas.
The loss of koala habitat across NSW
Trees help protect koalas from predators and harsh weather, but most importantly they provide them with food. Koalas prefer forests growing in better soils, and most of these forests have been chopped down for agriculture and housing. This has left many koalas living in small, isolated patches of poor quality forest.
If a particular patch of forest is fully occupied and they have to leave the area, young koalas may have to cross open spaces, including roads. They can be run over by cars, and many are attacked by dogs (which means that large dogs living in areas of koala habitat should be carefully supervised). A lack of suitable food and the stress of living in a fragmented environment may also make them more susceptible to disease.
Koalas have been declared a vulnerable species in NSW.
Koala conservation efforts
Koalas are totally dependent on particular species of eucalypt trees, which are being rapidly cleared in NSW. The only solution to the problems faced by koalas is to plant and keep trees for food and shelter in areas where the animals can reach them. The NPWS, together with voluntary conservation bodies, has been planting food trees for koalas in several areas, including Port Macquarie and Lismore.