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