One of a squirrel’s most distinctive features is her big, fluffy tail. In fact, about half a squirrel’s length is taken up by her tail.1 Other rodents like mice and rats have tails of similar length but without all the fluff. So does this big tail give squirrels any particular advantage?
It turns out that squirrels use their tails for all sorts of things. Fluffy tails help squirrels communicate with each other, perform arboreal acrobatics, and survive extreme temperatures.
Squirrels use their prominent tails to communicate with each other in a form of sign language. There are two main types of tail signals. The first is a small up-and-down undulation, and the second is a larger whipping motion.2 This whipping motion is a squirrel’s way of giving an alarm that a predator is near.3 It’s especially associated with indicating to other squirrels that a land-based predator, as opposed to a hawk or other aerial predator, is approaching.4
A High-Wire Balancing Act
Squirrels are often seen running along precariously thin branches and power lines. So how do they keep their balance? A long tail can help an animal run confidently through the treetops by serving as a counterbalance to the animal’s body weight.5 Think of the way a tightrope walker uses a long pole to stay upright on a wire. If a squirrel running along a narrow branch starts slipping off one side, she can move her tail in the opposite direction to balance herself out.
Of course, sometimes even squirrels take a fall. When that happens, their tails once again come in handy. A squirrel’s tail can act as a parachute to slow her down during a fall and then cushion her when she hits the ground.6
Staying Warm and Keeping Cool
Squirrels are active year round, so they need a way to stay warm in the winter and cool in the summer. Apparently, a big, furry tail is the perfect solution. One of the most common postures a squirrel will adopt is to sit with her tail curled over her head like a fuzzy umbrella. Not only does this tail umbrella protect a squirrel from the rain, but it helps her stay cool by shading her from the sun.6 Unsurprisingly, a squirrel’s furry tail also keeps her – and her babies – warm and cozy in colder weather.6
1 Webster, D., Parnell, J., & Biggs, W. (1985). Mammals of the Carolinas, Virginia, and Maryland. Chapel Hill and London: The University of North Carolina Press.
2 McRae, T. (2012). Predator-specificity of multimodal alarm signals in the eastern gray squirrel (Sciurus carolinensis). Open Access Dissertations, Paper 736. Retrieved from http://scholarlyrepository.miami.edu/cgi/viewcontent.cgi?article=1748&context=oa_dissertations
3 Jayne, K., Lea, S., & Leaver, L. (2015). Behavioral responses of Eastern grey squirrels, Sciurus carolinensis, to cues of risk while foraging. Behavioural Processes, 116: 53-61.
4 McRae, T. & Green, S. (2014). Joint tail and vocal alarm signals of gray squirrels (Sciurus carolinensis). Behavior, 151(10), 1433-1452.
5 Young, J., Russo, G., Fellmann, C., Thatikunta, M., & Chadwell, B. (2015). Tail function during arboreal quadrupedalism in squirrel monkeys (Saimiri boliviensis) and tamarins (Saguinus oedipus). Journal of Experimental Zoology, 9999, 1-11. Retrieved from http://www.academia.edu/14055165/Tail_Function_During_Arboreal_Quadrupedalism_in_Squirrel_Monkeys_Saimiri_boliviensis_and_Tamarins_Saguinus_oedipus_
6 Haupt, L. (2013). The urban bestiary: encountering the everyday wild. New York, NY: Little, Brown and Company.