Not a bear at all but a marsupial. Their closest relative is the wombat. The males are larger than females with southern koalas being 30% larger than the northern koalas. They can live for up to 17 years but males seldom live more than 10 years as they are vulnerable to attack by dogs and being hit by cars.Koalas prefer to move around just after sunset spending daytimes asleep in the fork of a tree. Koalas spend 75% of its time sleeping. Koalas have a slow metabolic rate due to their high-fiber, low nutrient diet. Because they store little or no fat, koalas must adopt strategies that conserve energy. Sleeping is one of them.
Just after sunset koalas move around and can often be heard "barking" aggressively at other koalas.
The Koala is the only mammal that can survive exclusively on a diet of eucolyptus leaves. They also seldom drink water as eucolyptus leaves are 50% water.
Koalas breed once a year. Mating normally occurs from September to March.
Gestation lasts 35 days, after which one koala is born.
The baby koala, "joey", is blind, hairless, less than one inch long and weighs less than 1 gram (0.035 oz).
It then crawls into its mothers pouch completely unaided, relying on its sense of smell, strong forelimbs and claws.
Once inside the pouch, baby koala attaches itself to one of the two teats and stays there drinking milk for the next six months.