The koala (Phascolarctos cinereus or inaccurately, koala bear[a]) is an arboreal herbivorous marsupial native to Australia. It is the only extant representative of the family Phascolarctidae, and its closest living relatives are the wombats. The koala is found in coastal areas of the mainland's eastern and southern regions, inhabiting Queensland, New South Wales, Victoria and South Australia. It is easily recognisable by its stout, tailless body; round, fluffy ears; and large, spoon-shaped nose. The koala has a body length of 60–85 cm (24–33 in) and weighs 4–15 kg (9–33 lb). Pelage colour ranges from silver grey to chocolate brown. Koalas from the northern populations are typically smaller and lighter in colour than their counterparts further south. It is possible that these populations are separate subspecies, but this is disputed.The koala is a stocky animal with a large head and vestigial or non-existent tail. It has a body length of 60–85 cm (24–33 in) and a weight of 4–15 kg (9–33 lb), making it among the largest arboreal marsupial. Koalas from Victoria are twice as heavy as those from Queensland. The species is sexually dimorphic, with males 50% larger than females. Males are further distinguished from females by their more curved noses and the presence of chest glands, which are visible as hairless patches. As in most marsupials, the male koala has a bifurcated penis, and the female has two lateral vaginas and two separate uteri. The male's penile sheath contains naturally occurring bacteria that play an important role in fertilisation. The female's pouch opening is tightened by a sphincter that keeps the young from falling out.Koalas are herbivorous, and while most of their diet consists of eucalypt leaves, they can be found in trees of other genera, such as Acacia, Allocasuarina, Callitris, Leptospermum and Melaleuca. Although the foliage of over 600 species of Eucalyptus is available, the koala shows a strong preference for around 30. They tend to choose species that have a high protein content and low proportions of fibre and lignin. The most favoured species are Eucalyptus microcorys, E. tereticornis, and E. camaldulensis, which, on average, make up more than 20 percent of their diet.
from:http://en.wikipedia.org/wiki/Koala