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anatomy index
Tail

Flying squirrels are sciuriuds. The word sciuridae comes from the Greek "skiouros", which means "shade tail". Being a nocturnal squirrel, the tail does not offer any shade for them ...just the diurnal squirrels get the shade effect! Of course, the tail of any squirrel is not really there to shade them from the sun.

What the tail does not do

The flying squirrel's tail is dorso-ventrally flattened. Let's get this out of the way right now. FLYING SQUIRRELS DO NOT STEER WITH THEIR TAILS. I repeat. FLYING SQUIRRELS DO NOT STEER WITH THEIR TAILS. The tail does NOT act as a rudder. There, I feel much better now. Many nature guides and web sites still state that flying squirrels employ their tails to steer. This is folly. As we mentioned, the tail is dorso-ventrally flattened. How on earth could a tail like that steer anything?

Famed flying squirrel researcher and author Nancy Wells (formerly Wells-Gosling) put it best:

"The tail's function during a glide is not fully understood, but referring to it as a rudder is misleading. The tail does not control glide direction. More accurately, it serves as a balancing organ, similar to the tail of a kite, stabilizing the glider in midair".


What the tail really does

We've already mentioned that the tail serves as a stabilizer in glide, much like the tail of a kite acts. This is evident if you watch our high speed videos capturing glides in slow motion.

The tail also serves as an added airfoil when braking for a landing.

Another use is for balance, especially when walking or running along precarious routes such as thin branches or branches moving with the wind, and when browsing the outer reaches of trees and shrubs for fruit, flowers, buds or nuts.

The position of a flying squirrel's tail can also provide clues as to its health, its hierarchy within the group, and its emotional state. A healthy flying squirrel will, when sitting, keep its tail up most of the time, with a marked bend away from the body and down, about two-thirds out from the base. A young adult flying squirrel will keep its complete tail down, somewhat, in the presence of an alpha squirrel. A mad flying squirrel will, when sitting, bend its tail towards its head. And a really mad flying squirrel will flick its tail in tandem with alarm calls.

The tail is passively employed in escaping the grasp of a predator's teeth or talons. Flying squirrels have "break-away" tails. Should a predator attack and grab a flyer's tail, escape is possible, if only  at the cost of part of its tail, not its life. The sight of a wild flying squirrel with half a tail is not an uncommon sight. The affected squirrel makes adjustments to this loss and can live a normal life afterwards.

tails
Tails of southern flying squirrel (left) and northern flying squirrel (right)
breakaway
Flyers possess "breakaway tails", which can often  allow them to deny a meal to a predator.