Fauna of New Guinea Guinea. However, the tree-kangaroos, which are mostly endemic to New Guinea, are different in appearance and behaviour. As suggested by their name, they are arboreal. They have long, thick tails which enable them to balance in trees, and large, strong forearms for gripping to trees. Two species of tree kangaroos are also found in Australia, they are believed to have migrated from New Guinea during the Pleistocene. The cuscus, family Phalangeridae, are a family of marsupials closely related to the possums of Australia. The cuscus have evolved in New Guinea, and are found throughout the island. Most species are dark
New Guinea is about the same amount as that found in the United States or Australia. A high percentage of New Guinea's species are endemic, and thousands are still unknown to science: probably well over 200,000 species of insect, between 11,000 and 20,000 plant species, and over 650 resident bird species. Most of these species are shared, at least in their origin, with the continent of Australia, which was until fairly recent geological times part of the same landmass (see Australia-New Guinea for an overview). The island is so large that it is considered 'nearly a continent' in terms of its biological