BIOLOGY & BEHAVIOR


There are over three hundred and fifty varieties of squirrels, ranging from the smallest African pygmy squirrels at five inches in length to the giant Asian squirrels at over three feet in length!

The squirrel family comprises approximately 40% of all mammals. The family is divided into seven sub-families, the most common of which are ground squirrels, flying squirrels and the tree squirrels.

The average life span for a squirrel is 3-5 years, but some have survived as long as twenty years in captivity!

Although male squirrels are notorious for chasing females all during the mating seasons (which occur between February and March and again between July and August), female squirrels are ready to mate only one day out of each season. A female can breed with up to thirty different partners in a 24-hour period!

Male squirrels are solitary creatures and usually leave their mates immediately after the babies are born. The males move on immediately after mating, primarily because the females will not allow them to stay. The protective mothers will usually not allow the father to return and stay with the babies, even after they are grown, because the male squirrels may harm the children to allow the mother to go back into heat sooner. The fathers sometimes are allowed to board with the family during the winter months.

Mother squirrels usually deliver two litters a year, with one to three babies each. Infants are born hairless, blind, and only about two inches from nose to tail. After about five weeks, the young squirrels’ eyes open for the first time. The mothers do not allow them out of the nest until they are around 10 weeks of age. At that point, they lose no time and immediately begin gathering nuts!

Urban squirrels are susceptible to growing accustomed to human treats. In fact, once they are weaned on pizza, chocolate, and the like, they will reject natural foods. For example, British scientists were recently baffled to discover an entire park of squirrels who have become addicted to nicotine after chewing on littered cigarette butts!

The teeth of squirrels are constantly growing throughout their lifetime. The front part of a squirrel’s tooth is made of hard enamel, while the back is made of softer dentin. This means that a squirrel’s teeth are self-sharpening! Squirrels wear down their teeth by gnawing constantly, even grinding in their sleep!

The average squirrel brain is about the size of a walnut and is considered a delicacy in the South, where it is eaten with scrambled eggs, fried and served head and all, or used in a stew called "burgoo". However, doctors in Kentucky recently warned squirrel eaters that squirrels may carry a fatal strain of "mad cow disease". As one journalist aptly stated, "When you think about it, squirrels seem a lot crazier than cows."

A squirrel uses its tail as a rudder for balance, a parachute during flight, an umbrella and raincoat during the wet season, a blanket for warmth, and a flag to alert other squirrels of danger.

Squirrels have been clocked in at speeds of up to 20 miles per hour. The average squirrel, however, usually scampers about at no more than 12 miles per hour.

Squirrels occasionally find their bushy tails tangled in knots, even elaborate braids, with the tails of other squirrels who share their nests. Groups of confused squirrels (and other rodents) have been discovered in this condition periodically since the early 1800s. If you find a group of such unfortunate squirrels, contact a wildlife rehabilitator immediately. Frantic to free themselves, squirrels have been known to try to gnaw through their own tails, so don't delay!

Sometimes the squirrels' tails become entangled because of tree sap, which essentially acts as a glue. In addition, this happens when people leave twine, fishing line and other strings around their yards. A mother squirrel will incorporate these materials into her nest, and the tails become entangled with the twine or string. Wildlife rehabilitators who find squirrels in this condition often have to amputate the tails because the string is so entangled in the tails. So please don't leave string-like substances in your yard!

Grey squirrels are able to eat countless acorns without becoming ill, although acorns contain polyphenols (commonly known as "tannic acid") and are poisonous to humans. Grey squirrels produce a special digestive enzyme which protects them from the tannic acid. However, red squirrels are not immune and can become fatally ill from eating too many acorns. Currently, red squirrels are nearly extinct in Great Britain, as the remaining few compete with aggressive grey squirrels for non-poisonous nuts.

Although ground squirrels hibernate for months at a time (some mountain varieties are only awake three months of the year), tree squirrels stay active during the winters. To survive the frigid temperatures, squirrels subsist on buried nuts and keep warm in groups (sometimes of a dozen or more) in their nests. Squirrels can sniff out an acorn through a foot of snow!