A young koala ©Getty Images

A young koala ©Getty Images

Even though it looks like a bear, the koala is not related to bears at all!  

It is one of Australia's best known and best-loved animals, and many people call it a koala bear, but its name is just koala.   It is a marsupial, and bears are not.   Marsupial babies are born at an early stage and finish their development in a pouch. 

The word 'koala' comes from an Australian Aboriginal word meaning 'no drink'. 

Habitat and Distribution (where it is found)

The koala is found in four states: Queensland, New South Wales, Victoria and South Australia.  They live in a range of habitats, including all tall eucalypt forests and woodlands.  They can only live where their food trees grow, although they also occasionally eat in non-eucalypt trees.

Body and Appearance

The dark patch on the chest marks where the male's scent gland is located. ©Getty Images

The dark patch on the chest marks where the male's scent gland is located. ©Getty Images

Koalas have soft, thick, grey or brown fur on their backs.  The fur on the stomach is cream or white.  Koalas that live in the southern parts of Australia have thicker fur than those in the north because of the cold winters, whereas the koalas in the northern part of the country live in warm to hot weather most of the year so have thinner fur. 

A koala has a large, hairless nose and round ears.  They have an excellent sense of smell. Koalas don't have tails.  Adult koalas measure between 64 to 76 centimetres in length and weigh between 7 and 14 kilograms.

Females have a backward facing pouch, meaning it is upside down. They grip muscles tight to close the opening and prevent a joey falling out. Males have a dark stripe on their chest which has a gland that,  as they climb, marks trees with a scent that warns other males not to climb that tree. 

Koalas have two thumbs on each front leg to help them climb trees. ©Getty Images

Koalas have two thumbs on each front leg to help them climb trees. ©Getty Images

Mammals have a part in the  body called a caecum (say see-cm), but in koalas it is unusually long, about 200cm.  It contains bacteria to break down the tough fibres of the leaves koalas eat so that nutrition can  be absorbed into the body.  

Koalas have strong, sharp claws and long toes to help them climb. The front paws have two thumbs to help them grip branches strongly - the two thumbs go on one side of the branch for better grip, the rest of the claws on the other.  The second and third toes on the back legs are joined together to form a grooming claw. The four legs are about the same length. Although mostly silent, koalas communicate with each other using a range of noises ranging from one that sounds like a loud snore, and a burping sound, to a loud bellow.

Koalas eat the leaves of some kinds of eucalyptus trees ©Getty Images

Koalas eat the leaves of some kinds of eucalyptus trees ©Getty Images

Diet

Koalas eat the leaves and young shoots of some kinds of eucalyptus (say you-kuh-lip-tus) trees, often called gum trees. In Australia there are over 600 species, or kinds, of eucalypts, but koalas only eat about 20 species. Within a particular area, there will be only three or four species of those eucalypts that will be regularly eaten by koalas. A variety of other species, including some non-eucalypts, are eaten by koalas occasionally or used for just sitting or sleeping in.

The koala's bony bottom helps it sit in trees. ©Getty Images

The koala's bony bottom helps it sit in trees. ©Getty Images

Different species of eucalypts grow in different parts of Australia, so a koala in Victoria has a very different diet from one in Queensland even though it may seem to be the same. Koalas don't often drink water, as they get moisture from eucalyptus leaves. However, in a severe drought, there is less moisture in leaves so koalas will then need to find water to drink.

Koalas spend much of their time asleep. The reason for this is that so much of their body's energy is needed to digest their food: eucalyptus leaves are very tough and hard. The leaves provide very little nutrition, so a koala has to eat lots of them to get enough nutrition, approximately a kilogram per night for an adult.  The leaves are poisonous to most mammals.

Like its closest relative, the wombat, a koala has a bony bottom which helps it wedge itself in trees.

Koalas spend a lot of time sleeping ©Getty Images

Koalas spend a lot of time sleeping ©Getty Images

Behaviours

Koalas spend nearly all their time in the trees using their sharp, curved claws and long toes to climb about and to hold on to the tree branches. They sleep most of the day, and feed and move from tree to tree mainly at night.  Sometimes they move about in the daytime. Sometimes they are seen on the ground, and can move quite quickly.  

Each koala has a home range made up of several trees that they visit regularly. They normally do not visit another koala's home trees except when a male is looking for a female to mate with. 

Life Cycle

Females usually have one joey per year. ©Getty Images

Females usually have one joey per year. ©Getty Images

Breeding season is generally from August to February. During this time the males will be heard bellowing as they compete for females. At this time the young from the previous year are ready to leave their mothers and become independent.  Usually a female has one young each year, but may not breed in some years.

A baby koala is called a joey

About 35 days after mating, a tiny baby called a joey is born. It is about 2 cm long, weighs less than 1 gram and is pink, hairless, blind and without ears. Amazingly, this tiny creature travels up its mother's belly and finds the entrance to the pouch. Inside the pouch, it attaches itself to a teat that immediately swells inside its mouth so that the joey cannot let go and lose the teat. The female is able to tighten muscles at the opening of the pouch to prevent the baby falling out.

The joey stays in its mother's pouch for several weeks after it is born and then travels on here back ©Getty Images

The joey stays in its mother's pouch for several weeks after it is born and then travels on here back ©Getty Images

The female carries her baby in the pouch for 6 or 7 months after it is born. The baby feeds on its mother's milk inside the pouch. Between 22 and 30 weeks of age, its mother starts feeding the joey a substance called pap, which is formed from pre-digested food and her droppings.  This is important, because it contains bacteria from the mother's intestine that will enable the joey to digest the toxic eucalyptus leaves.  It is fed to the joey for several weeks before it leaves the pouch.  After it leaves the pouch, the baby travels around on its mother's back, but continues to drink milk until a year old.  It is then often referred to as 'back young', now that it is no longer 'pouch young'. Generally this is when a young one leaves its mother, but if she does not breed then the young one stays longer.

An orphaned joey being hand reared by a wildlife carer. ©Getty Images

An orphaned joey being hand reared by a wildlife carer. ©Getty Images

Conservation status and threats

Koalas are classified as Vulnerable.  Habitat loss is a major threat for koalas as forests are cleared.  Koalas are hunted by dingoes,  feral (once domestic but now wild) dogs and foxes.  Goannas, wedge-tailed eagles, and large owls are a danger to baby koalas. If there are too many koalas in a small place, usually because much of the forest is cut down, koalas can become stressed, and then ill.  

Many koalas are killed on the roads at night. When live pouch young are found in a female that has been killed on the road, trained wildlife carers can hand rear the young. 

Watch a video of koalas in a zoo: you can see them move and eat, see close ups of their hands  and a close up of the male's scent patch. You can also hear the male bellow.

http://animals.sandiegozoo.org/animals/koala

Read more

https://www.savethekoala.com/about-koalas/physical-characteristics-koala