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Koala (Koala Bear, Bangaroo, New Holland Sloth)

Can get chlamydia, just like humans

Order: Diprotodontia Prev. Marsupialia

Family: Phascolarctidae prev. Phalangeridae

Genus & Species: Phascolarctos cinerus


Koalas are small, furry marsupials of Australia that resemble a cross between a bear and a sloth. In habits they resemble the loris and the sloth. And yet they carry their underdeveloped young in a pouch, making them marsupials like the wombat or opossum.

Sexual dimorphism is present in this species, with the males being larger than the females. They grow to heights of 24-30 in (60-75 cm). The males weigh 14.3-26 lbs (6.5-11.8 kg) , and the females weigh 11.2-17.4 lbs (5.1-7.9 kg). The koalas in the north are smaller than those in the south. Koalas are unusual looking mammals. The body is short and stocky, and is tailless except for a short rounded stump where the tail would be. The ears are large and tufted, the eyes are small with vertical slits for the pupils, and the snout is large, prominent, and black. The forelegs are slightly longer than the hindelegs and the hindelegs are slightly stickier than the forelegs. All four feet are used for grasping. The forefeet have five digits, with the first two thumbs opposed to the last three fingers. On the hindefeet, there are again five toes, with the first one much smaller and opposed to the rest. The second and third toes are joined together. All the feet end in sharp claws. Koalas lack canine teeth. The males have a sternal scent gland located on their stomach, which they use to communicate with other koalas. Koalas have the thickest coat of all the marsupials. It is ash-grey in colour, with a brown tinge on the upper quarters. The hindquarters are tawny and the underparts are white. Koalas in the north have a short coat; koalas in the south have a longer coat with the backhairs thicker and longer than those on the belly.

Koalas are distinct from other marsupials in that their pouch opens to the back, not to the front. It has "drawstring" muscles that, when pulled taught, will close the pouch.

Koalas are avid tree climbers and use their feet to grasp the branches. They are very strong swimmers but are awkward on land. They have a life span of 13-18 years in captivity, shorter in the wild.


Koalas are mostly found in eastern Australia, from northern Queensland to southwestern Victoria. They are extinct in southern Australia, but efforts are being made to reintroduce them there. They have been introduced to Flinders Island (S. Australia) and the Phillip and French Islands off Victoria, as well as western Australia.

Koalas are fussy eaters and therefore are found only in small patches in eucalyptus forests and woodlands where the vegetation is suitable. Koalas are tree dwellers, sleeping for 20 h curled in a branch during the day and eating at night. They live solitary lives, getting together only to mate.


Koalas are strictly herbivorous in nature, feeding only on the leaves of 120 out of 600 species of eucalyptus (or gum) trees. They feed primarily on 12 species, including the manna gum and the red gum. They eat roughly 1-2 lbs of leaves each day, some of which enters cheek pouches to be eaten later. To cope with this diet, their digestive system is specialized to handle gum leaves.

Eucalyptus trees produce toxins during some stage of their growth, and therefore koalas must have a good sense of smell to know which leaves are edible and which leaves are not.

Koalas will eat soils to gain minerals, and drink very little water as the leaves they eat provide most of it for them.


Koalas have few natural enemies, being killed mainly by dingos, domestic dogs, and cars. When koalas get stressed, they become susceptible to disease, and large numbers have been wiped out by diseases such as chlamydia, conjunctivitis, cystitis, and leukemia. Their biggest threat is man, who at one time nearly hunted them to extinction for sport, and, after 1908, for their coat. By 1824, over 2 million koala pelts had ben exported. Today, measures are being made to protect koalas, but forest fires and land clearance still take their toll. There are 40000-80000 koalas left in the wild.


Females reach sexual maturity at 2-3 years, males at 3-4 years. The breeding season is from September to January in the south and November to February in the north. 1 young, rarely two, is born after a 35 day gestation period. It is blind at birth and is 3/4 in (19 mm) long and 0.5 g in weight. It drags itself into the pouch by following a trail of saliva laid down by the mother and grabs hold of one of two nipples. After 22 weeks, the eyes open and the Joey looks out of the pouch. By 24 weeks it is fully furred. At 36 weeks it emerges from the pouch and clings to its mother's back until 48 weeks, when it becomes adventurous and leaves its mother for short periods of time. It goes off on its own after 1 year.


There are 3 subspecies of the koala: P. c. victor, P. c. cinerus, and P. c. adustus.


1. "Koala" Funk & Wagnall's Wildlife Encyclopedia, pg 1215, vol 10, 1974, USA, BPC Pub Ltd
2. "Koala" Wildlife Fact File, USA, IM Pub