Two groups of rodents are referred to as flying squirrels. They are:

• the subfamily Petauristinae of the Sciuridae, the group that includes the typical squirrels. Flying squirrels of this group are mainly found in Asia, but extend to Europe (Finland) and North America.
• the scaly-tailed flying squirrels of the family Anomaluridae, found in Africa.

Although the wrist-winged gliders (subfamily Petaurinae) of the marsupial family Petauridae, and the colugos, the "flying lemurs" of the order Dermoptera, are similar to flying squirrels, they are unrelated, and the similarities are an example of convergent evolution.

There are 43 species of flying squirrel worldwide. There are about 36 species in the subfamily Petauristinae, arranged in around 13 genera. The largest is the Woolly Flying Squirrel, Eupetaurus cinereus, found in Kashmir. The two species of the genus Glaucomys are native to North America, and it is these that are most often meant when the name "flying squirrel" is used in English. They are:

• Glaucomys sabrinus, the Northern Flying Squirrel, whose range extends from Alaska to Virginia (25 geographical subspecies are recognised, two of which (G.s. fuscus and G.s. coloratus) are endangered in the USA);
• G. volans, the Southern Flying Squirrel, whose range extends from the south-eastern Canada to parts of Central America (10 geographical subspecies are recognised, one of which (G.v. volans) is endangered in Canada);

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Flying squirrels do not fly in the same sense as birds or bats - they do not employ powered flight . Rather, they glide: once they have launched themselves into the air, they have no means of forward propulsion. They are true gliders: that is, unlike a human-made sailplane, they do not use upcurrents in the air to soar, so they will lose height during a glide. However, they can steer themselves very adroitly while in a glide. They do not steer with their tails, as is commonly but erroneously reported. Steering is accomplished by adjusting tautness of the patagium and positioning of the forelegs. The tail acts as a stabilizer in flight, much like the tail of a kite, and as an adjunct airfoil when "braking" prior to landing on a tree trunk.

Popular culture reference

• The Rocky and Bullwinkle Show
• Samurai Champloo

External links

• Glaucomys.org, general info and pictures
• Animal Diversity Web: Pteromyinae, classification
• Flying Squirrel Central, a directory to over 150 sites