Pigs, several additional species of rats, and the ancestor of the New Guinea singing dog were introduced with human colonization.
Prior to the 1970s, archaeologists called the single Pleistocene landmass by the name Australasia, although this word is most often used for a wider region that includes lands, such as New Zealand, which are not on the same continental shelf.
Other than bats and some two dozen indigenous rodent genera, there are no pre-human indigenous placental mammals.
The highest peaks on the island of New Guinea are: Another major habitat feature is the vast southern and northern lowlands.
Stretching for hundreds of kilometres, these include lowland rainforests, extensive wetlands, savanna grasslands, and some of the largest expanses of mangrove forest in the world.
These are the island's major river systems, draining roughly northwest, northeast, southwest, and southeast, respectively.
Many have broad areas of meander and result in large areas of lakes and freshwater swamps.