The Phalangeridae are a family of mostly nocturnal marsupials native to Australia, New Guinea, and Eastern Indonesia, including the cuscuses, brushtail possums, and their close relatives.

Besides the large size, other key features distinguishing phalangerids from other possums include the presence of bare skin on at least part of the tail, and low-crowned molar teeth.

Like some similar species, they have a large cecum to ferment this highly fibrous food and extract as much nutrition as possible.

The only exception to these general rules is the ground cuscus, which is carnivorous, and is also less arboreal than other phalangerid species.

The adults are typically solitary, defending territories marked by scent-gland spray, odiferous saliva, urine, or dung.