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Fox Squirrels
Fox squirrels are found throughout the eastern United States; their natural range extends from Florida, north to Canada, and west to the Dakotas, Colorado, and Texas, but they are not found in New England.
Fox squirrels were introduced to Southern California especially Los Angeles by Fish & Game sometime in the 1930's I believe. They dropped them off at different parks and campuses including I think Larchmont Park.
In natural conditions, fox squirrels live to 7 or 8 years of age, although one individual lived to 18 years of age in captivity. They tend to be larger in the northern part of their range than in the southern part of their range. Their bodies measure 450 - 700 mm total length, 200 - 330 mm tail length, 51 - 82 mm right hind foot length, and they range in weight from 500 - 1000 grams. Fox squirrels have both a summer and winter coat, and therefore molt twice each year. The spring molt begins in March, whereas the autumn molt begins in September, but the tail only molts once each year during the summer.
Fox squirrels have four sets of whiskers located above and below the eyes, on the underside of the head in front of the throat, and on the nose. Whiskers, also known as vibrissae are touch receptors that provide the animal with information about its immediate surroundings. Fox squirrels have very good eyesight even in dim light, and a wide field of vision. They also have a well developed sense of smell and hearing.
Squirrels have upper and lower incisor teeth followed by a gap called a diastema. The diastema is where the canine teeth would normally be found in carnivorous animals such as cats or dogs, or omnivorous animals such as monkeys. Behind the diastema are the cheek or grinding teeth which consist of premolars and molars. As with other rodent species, the incisors continuously grow to compensate for the enormous amount of wear that comes from a herbivorous diet. Young squirrels have milk teeth which are replaced by permanent teeth when they are between six and twelve months old.
Fox squirrels are highly adapted for climbing trees and fatal falls are rare. Adaptations for climbing trees include tough curved claws for climbing and they can leap considerable distances using powerful hindlimbs. Tails are used for balance when running and leaping between trees, and held over the back of a resting animal.
Juvenile squirrels are born without hair and their eyes remain closed for about one month. Young begin to venture outside of their nest at 7 - 8 weeks of age, but generally don't travel on the ground until closer to 3 months of age.
Juvenile males are more likely to leave the natal area and disperse than are juvenile females. Dispersal usually occurs during the fall and young males move between 1 and 16 kilometers away from their natal nest. The longest recorded dispersal is 100 km. Dispersal is a high cause of mortality among males, which results in a slightly female biased sex ratio.
Fox squirrels have large overlapping home ranges and are non-territorial. Fox squirrels are most commonly found in oak-hickory forests. In the south they will also be found in live oak and mixed forests, cypress and mangrove swamps, and in piney areas.
Fox squirrels are generalist feeders and their diet is dependent upon the area in which they are found. Squirrels feed heavily on nuts, flowers, and buds of 24 oak species, and 10 species of walnut, hickory and pecan. Other food items include the fruits, seeds, buds or flowers of maples, mulberry, hackberry, elms, buckeyes, horse chestnuts, wild cherries, dogwoods, hawthorne, hazelnut and ginkgo. Pine tree seeds and pollen cones are readily eaten including cedar, hemlock, pines, and spruce. Fungi are also consumed when readily available in summer, as are cultivated crops in winter. Animal food items include bones, bird eggs, nestlings, and frogs.
Food consumption peaks in summer or autumn and decreases in winter. Autumn rates of food consumption exceed energetic needs by 32% so that the animals can increase their weight before the onset of winter. Fox squirrels are classic scatterhoarders. They carry nuts in their jaws and bury them in various locations within their home ranges. Olfaction and memory are used in locating their caches.
Tree dens are another type of nest used by fox squirrels. These are holes or cavities in the main trunks of trees which are also lined with soft material. Formation of den cavities requires 8 - 30 years, and are more common in deciduous trees than in coniferous trees. Squirrels often use dens in winter months and dreys in summer months.
Skeleton and skull of a squirrel -
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