The genus Petaurus contains flying phalangers or wrist-winged gliders, a group of arboreal marsupials. There are six species, sugar glider, squirrel glider, mahogany glider, northern glider, yellow-bellied glider and Biak glider, and are native to Australia or New Guinea. Flying phalangers are typically nocturnal, most being small (sometimes around 400 mm, counting the tail), and have folds of loose skin running from the wrists to the ankles.