Flying phalangers are marsupials. While listed as synonymous with flying squirrels in certain dictionaries (shifty-eyed glance at Webster 1913), they are not related to those species of rodent. True flying squirrels are rodents of the genus Glaucomys, and are native to North America, while flying phalangers are, well, phalangers (marsupials with grasping hands and feet), and most belong to the genus Petaurus, though Acrobates and Petauroides also contain one "flying" species each, respectively. All together, there are eight species, and all are native to Australia.

Perhaps the most well known flying phalanger species is the sugar glider, which has become popular as an exotic pet. As is typical of flying phalangers, the sugar glider prefers to go about its business at night, is small (usually around 400 mm, counting the tail), and has folds of loose skin extending from its wrists to its ankles. Flying phalangers use this skin to glide from tree to tree by jumping and holding out their limbs spread-eagle. Catching the air in this way, they're able to travel for distances as long as 100 meters. Beside the distinctive skin folds, flying phalangers also have large, forward facing eyes, short though pointed faces, and long, flat tails which are used as rudders while gliding.

There are eight species of flying phalanger: Petaurus breviceps, the sugar glider; P. australis, the yellow bellied or fluffy glider; P. gracilis, the mahogany glider; P. abida, the Northern glider; P. biancensis, the Biak glider; and P. norfolcensis, the squirrel glider, plus Petauroides volans, the greater glider, and Acrobates pygmaeus, the feather tail glider. The two species outside of Petaurus (the feather tail and the greater glider) represent the extremes of flying phalanger size. The feather tail is tiny and weighs in at a mere 12 grams, while greater gliders are usually around 1.5 kilos and are 900 mm (counting tail) in length. All of the animals listed are omnivores, and eat tree sap, gum, nectar, pollen, and insects, along with more mythical sounding foods such as manna and honeydew (not the melon). Most flying phalangers seem to be solitary, though the yellow bellied and sugar glider both are known to live in groups.

While greater, Biak and sugar gliders are relatively common, most of the other species are rare, or, in the case of mahogany glider, endangered. Mahoganies are so uncommon that they weren't seen for more than a hundred years after their original discovery in 1883. Nearly a month after they were rediscovered in 1989, their habitat was cleared for plantations, and another population wasn't found until 1991.

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