In Neocene Australia and New Guinea had merged to unite land massive named Meganesia. This continent continuously moves to the north, to the equator, “crushing” edges of lithosperic plates of Indonesia. Actually, this circumstance became the reason of raising of northern part of Meganesian lithosperic plate. Movement of continent has caused the considerable changes in climate of territories included in continent. The northern Meganesia in Neocene is in the area of equatorial climate that has positively had an effect on nature of continent. The north is covered with rich rainforests. And in forest swamps rivers originate and flow to the south and carry water to areas represented rigorous waterless deserts in Holocene. Rainforests of the north of Meganesia are rich in life. Various birds, reptiles and amphibians, and also unnumerable species of insects live here. Besides, the forest canopy is inhabited by various small and medium-sized mammals, and large species of mammals are found in underbrush. Among them there are descendants both of native Australian and New Guinean species, and descendants of species introduced by people. Rainforest is a habitat of rather large species of marsupial mammal which is named marsupial biruang. It belongs to group of carnivorous possums classified in family Carnopossumidae. Its close relatives are huge marsupial grizzly living in the south of continent, and marsupial panda – smaller species from mountain areas at the east of the continent. Marsupial biruang is the smallest representative of carnopossumids: weight of adult animal is only about 60 kg. It is the ecological analogue of Malayan bear, or biruang, known in human epoch – hence the name of this species. Marsupial biruang has robust constitution and rather short limbs. Similarly to all carnopossums, it has very short tail which does not take part in tree-climbing. On paws of animal long hooked claws grow; with their help marsupial biruang easily gets on high trees. Fingers of animal are mobile and permit it to gather very small objects and to catch insects. The wool of this animal has black or dark brown color, and only above eyes there are two light grey spots. At young animals spots above eyes are absent. On hands and feet wool is thin, and through it grey skin of animal is visible. Eyes of animal are directed forward, and provide enough wide sector of three-dimensional vision. Ears at marsupial biruang are short, rounded, slightly jutting out from wool. At this animal there are rather short muzzle and increased forward cutters. Molars are obtused: their shape is characteristic for omnivores. Marsupial biruang uses for life all levels of rainforest – from underbrush up to forest canopy at height over 20 meters. This is sluggish single animal marking borders of territory with the help of musky liquid secreted by two glands at the root of tail. This animal is omnivorous and easily finds enough of food. It eats fruits of various tropical trees, sappy leaves and stalks of epiphytic plants. Also this animal catches large insects and digs out of ground worms and grubs. If the opportunity is represented, marsupial biruang catches little mammals and ravages nests of birds. Any animals from insects and snails up to vertebrates weighting up to 3 – 4 kgs become its prey. Having caught prey, marsupial biruang perches on wide strong branch of tree, sits on hinder legs and eats food, holding it in forepaws. After meal the animal licks wool by long tongue, and “washes” by forepaws like cat. Marsupial biruang is active in day time, and only in hottest time of day sleeps till some hours, having chosen a shady place. At this species of marsupials the female is larger and heavier, than the male. Animals do not form constant pairs, and meet only for the period of pairing. The pouch at the female opens forward – when female swarms up a tree, such position of pouch is safer for the large cub. The female bears only 2 – 3 rather large cubs (large to measures of marsupials – newborn marsupial biruang weighs about 10 grammes). Some months later only one cub from the litter usually survives. The female looks after it for a long time: the cub stays in pouch till about seven months. Having left the pouch, it follows the female and learns to search for food till about three – four months. At this time the female can couple with another male and bear new posterity. When the new cub is born and gets into a bag, the female starts to show aggression to the previous cub, and it passes to independent life. Sexual maturity at marsupial biruang comes at the age of four years, and life expectancy reaches 40 years and more.