Tree squirrels are the members of the squirrel family (Sciuridae) commonly just referred to as “squirrels.”
They get their common name from the fact that they are found in wooded and urban areas with trees.
There are 122 species of tree squirrels.
Tree squirrels inhabit the forests of Europe, Asia, North America, and South America.
Adult tree squirrels can have a lifespan of 5 to 10 years in the wild; but most of young don’t make it to their first year.
Variation in body size is considerable. The largest is the Indian giant squirrel at 1 meter (39 inches) in length and weighs up to 2 kilograms (4.41 pounds). The smallest is the African pygmy squirrel at 7 to 10 centimeters (2.8 to 3.9 inches) in length and just 10 grams (0.35 ounce) in weight.
Tree squirrels have slender, lanky bodies, long, muscular limbs, and furred feet.
Squirrels’ soft, dense fur is moderately long in most species but can be very long and almost shaggy in some. Colour can vary from brown to red to black or even white.
The tail is about as long as head and body or appreciably longer. Furred from base to tip, the tail appears bushy and cylindrical when the hairs grow evenly around the tail.
Their large, bright eyes convey an alert demeanour, and the broad, short head tapers to a blunt muzzle adorned with long whiskers.
The rounded ears, small in relation to body size, are densely covered with short, fine hairs, which form a long tuft at the tips of the ears in some species.
Like other rodents, they have four front teeth that never stop growing so they don’t wear down from the constant gnawing.
The forefeet have four long digits plus a short, stubby thumb, and the five-toed hind feet are narrow or moderately wide. The bald soles of the feet take the form of prominent, fleshy pads.
Because the ankle joints are flexible and can be rotated, squirrels can rapidly descend trees headfirst with the hind feet splayed flat against the trunk.
Claws are large, strong, curved, and very sharp, which enables tree squirrels to navigate vertical surfaces and slim branches.
They are arboreal, spending most of their time in trees. They nest, avoid predators and harvest food in trees.
Tree squirrels are diurnal (active during the daytime). They enjoy baking in the sun near their nest hole in the early morning.
Tree squirrels feed mostly on plant material, including seeds, nuts, acorns, tree buds, berries, leaves, and twigs. However, they are opportunists and also eat fungi, insects, and occasionally birds’ eggs and nestlings.
One well-known trait of some species of tree squirrels is the gathering and storing of nuts and seeds for the winter. These squirrels are scatter-hoarders; they will gather nuts and seeds and store them in any accessible hiding place, usually by burying them. They don’t dig up all of their buried nuts and seeds, which results in more trees!
Squirrels use their keen sense of smell to search for buried food, but can dig numerous holes in the process. This may become an annoyance to gardeners with strict landscape requirements, especially when the garden contains edibles.
Many tree squirrel species have adapted to human-altered environments such as rural farms, suburban backyards and urban parks; and because they are diurnal they have become perhaps the most familiar wildlife to most humans.
Tree squirrels don’t dig holes in trees. They don’t eat wood. They simply take advantage of pre-existing holes in trees, and live in those. When no knot hole or decomposed hole is available, squirrels will often build a nest out of sticks and leaves.
Tree squirrels breed once or twice a year and give birth to two to eight offspring after three to six weeks, depending on species.
The word squirrel comes from the Greek words skia meaning “shadow” and oura meaning “tail”; in other words, “tail that casts a shadow.”
White squirrels are almost always a white version of the eastern grey squirrel. There are a few types of genetic aberrations that cause the white coats. The first is albinism, caused by a mutation on a gene that codes for pigmentation. Albinos have red eyes. The other is a white morph, caused by a different gene. It is a naturally occurring trait of eastern grey squirrels that is very, very rare.