The Amazing Spectacular Squirrel Tail

There is little doubt that the most beautiful and instantly recognizable physical characteristic of the squirrel is its tail. Tree squirrels especially are endowed with a long, thick, bushy tail, often equal in length to the rest of the squirrel's body, that even many squirrel haters can't help but grudgingly admire. The squirrel sitting on a branch in its "classic" pose--on its hind feet, a nut in its paws, tail in the "S"-curve over its back--may, for many city and suburb dwellers, be the most familiar image of wildlife. The squirrel's tail is such a stunning feature that back in 1899, one writer noted that "no one can see him put it into such graceful curves along with his delightful postures, without feeling that he is posing for esthetic effect."

"Classic" squirrel pose

The tail is, for the squirrel, much more than a nice decoration. In fact, it serves more functions than most people would likely ever imagine. In Squirrel Book, his book of squirrel essays and stories, Eugene Kinkead noted that the squirrel's tail

serves as a sunshade; as a blanket in cold or stormy weather; as an expressive aid to communication...; as a counterbalance in effecting marvelously quick turns; as an aerial rudder when its owner leaps from branch to branch, and as a parachute to soften the impact of occasional falls.

 Protection from the elements is one of the more obvious uses of the squirrel's tail. The very name "squirrel" comes from two Greek words, skia, meaning "shadow," and oura, meaning "tail." For some ground squirrel species living in hot climates, such as the South African ground squirrel, this function is especially important. Using the tail as a parasol to provide shade from the sun can lower the temperature by as much as five degrees Fahrenheit, enabling the squirrels to search for food even in the midday heat.

South African ground squirrel in the
shade of its tail

The tail can also provide protection against cold weather and precipitation.

Eastern gray squirrel using its tail for
protection from the snow

The tail helps keep its owner comfortable in less obvious ways, as well. Squirrels can unconsciously regulate the blood flow to the tail to aid in thermoregulation, or the control of the animal's body temperature. A long tail, which has a large surface area per unit of length, tends to lose heat rapidly. In hot weather, the squirrel increases the amount of blood flow to the tail, dissipating more heat and helping it to cool off. In cold weather, the amount of blood flow to the tail is reduced, conserving more heat and helping the squirrel to stay warm.

There is another important use for the heating of the tail: to help protect the squirrel against predators, especially snakes. Many species of squirrels, especially ground squirrels, live in areas where they are threatened by venomous snakes. One strategy that the squirrels have to protect themselves is tail flagging, which involves facing the snake directly, and waving the tail rapidly back and forth. At the  same time, the squirrel is increasing the blood flow to the tail, causing it to heat up. Snakes such as rattlers and cobras hunt more by detecting heat than by sight. Tail flagging together with the heating of the tail causes the squirrel to look larger and more threatening to the snake.

California ground squirrel tail flagging
at a rattlesnake

The tail also helps tree squirrels to maintain balance so that they can move about quickly and confidently among the branches high above the ground. It can even act as a counterbalance while the squirrel is resting or eating.

Indian giant squirrel with
tail as a counterbalance

As important as the tail is to a squirrel, it's not surprising that squirrels put some time and effort into taking care of their tails. To anyone who pays attention while watching the wildlife in their neighborhood, a squirrel stopping to groom its tail should be a common sight. Some observers have even made the mistaken assumption that a squirrel was using its tail as a napkin to wipe its face, when in fact it was grooming the tail.

South African ground squirrel grooming its tail