The Sunda flying lemur does not belong to the prosimian group like true lemurs, but is in a zoological order of its own, Dermoptera or “skinwings”, which has only one genus and two species: the Philippine and Sunda flying lemurs. The latter is mottled grayish or brownish on its upper parts and is paler below. Flying lemurs do not actually fly, but glide from one tree to the next, by means of the patagium, a membrane that stretches from their forelimbs to their tail. There is little information about their life span but the oldest known individual in captivity lived to 17.5 years old.
Sunda flying lemurs live either solitary or in small groups that are loosely connected. They can be territorial as regards foraging and sleeping areas. They are mainly nocturnal. They are strictly arboreal and in the daytime they sleep high within dense foliage in the treetops or in holes in trees. With all four of their feet, they cling on to the trunk of a tree or the underside of branches. Climbing involves stretching out their two front legs and then bringing up their two back legs, which results in an awkward hopping. They can glide more than 100 m with minimal loss in elevation. When threatened they either climb higher up or remain motionless. These animals are quite helpless if on the forest floor.