THE koala bear is not a bear at all. Its closest relative is the wombat, the world's largest burrowing animal, and they share the characteristic marsupial feature, the pouch. The koala, Phascolarctos cinereus , lives in the southeast of Australia. It has a pair of tufted ears and a prominent bear-like snout. Its fur is thick, insulating it from temperature extremes. In the north, it has short brown fur and weighs no more than six kilograms. In the south, it has long, ash-grey fur and can reach 13 kilograms. They enjoy a varied diet, eating acacias, kapok, and native cherry leaves besides the well-known eucalyptus. Koalas sleep and lounge for 19 hours every day and live mostly at night - eating between dusk and midnight. . They lead solitary lives, meeting other koalas only to mate, care for the young, and defend territory. The mating season is from September to January and a female produces a single cub a year. The gestation period is about 35 days. At birth, the koala cub is hairless and the size of a peanut. It lives in its mother's pouch for seven months and is dependent on her for a year. Massive habitat clearance in Australia is the koala's No 1 enemy but koalas are also vulnerable to diseases such as conjunctivitis. Though not yet considered endangered, koalas could easily be threatened if habitat loss continues at the present rate.