Once the young begins to feed on leaves growth is rapid. Toward the end of their pouch life the young feed regularly on material passed through the mother's digestive tract (Nowak, 1997). Young have a pouch life of 5-7 months, feeding on milk or predigested leaves that are nontoxic, and are weaned at 6-12 months (Nowak, 1997). The young weigh less than 0.5 grams when born, and attach to one of the nipples in the pouch. Litters generally consist of only one young but twins have been reported (Nowak, 1997). The gestation period is 25-35 days with births occurring in mid-summer (December-January). Females are seasonally polyestrous, with an estrous cycle of about 27-30 days, and usually breed once every year (Nowak, 1997). Males are fertile at two years but usually don't mate until they reach four simply because competition for females requires larger size. Average basal metabolic rate 5.744 W AnAgeįemales are sexually mature at two years of age.The first digit of the hind foot is short and greatly broadened while the second and third digits are relatively small and partly syndactylous but have separate claws (Nowak, 1997). On the forepaw the first and second digits oppose the other three which enables the koala to grip branches as it climbs. The paws are large, and both fore and hind feet have five strongly clawed digits. The coat is generally shorther and lighter in the north of range. The rump is often dappled with white patches and the ears are fringed with long white hairs (MacDonald, 1984). There is white on the chin, chest and inner side of the forelimbs(MacDonald, 1984). Koalas have dense, wooly fur that is gray to brown on top and varies with geographic location. Average weights are: in the south, males-11.8 kg, females-7.9 kg in the north, males-6.5 kg, females 5.1 kg (MacDonald, 1984) "Males are up to 50% heavier than females, have a broader face, somewhat smaller ears, and a large chest gland (MacDonald, 1984)." Females have two mammae and rather than a chest gland, have a pouch that opens to the rear and extends upward and forward (Nowak, 1997). In the south, males have an average head-body length of 78 cm and females 72 cm (MacDonald, 1984). In both areas they exhibit sexual dimorphism with the males being larger. Koalas from the southern end of the range are generally larger in size than their northern counterparts. The koala is confined to eucalyptus forests below 600 m. Koalas are arboreal, remaining mostly in the branches of the eucalyptus trees, where they are able to feed and stay out of reach of their predators. They have been introduced to western Australia and nearby islands (LPZ, 1997). The koalas live in eastern Australia and range from northern Queensland to southwestern Victoria.
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