Fox squirrels are medium-sized tree squirrels with a long, furry tail. Fur color varies greatly in this species, from overall pale grey to black with white feet. The most common fur color is reddish-brown. Often the hairs are reddish tipped with brown, giving these squirrels a frosted look. The fur on their belly is always lighter in color.
Fox squirrels have very sharp claws and muscular bodies. This enables them to climb trees and other objects extremely well.
Fox squirrels are found throughout the eastern and central United States. They occur as far south as northeastern Mexico and as far north as south central Canada. They have been introduced into cities in the western United States as well.
Fox squirrels prefer open, savannah-like habitats, where trees are widely spaced and the understory is open. They are most common in oak-hickory forests but are also found in live oak, mixed forests, cypress and mangrove swamps, and pine forests. Because of this habitat preference they tend to do well in urban and suburban settings. They are rare in heavily forested areas, unlike their close relatives grey squirrels.
Fox squirrels need large trees with cavities or holes in them for building nests to raise their young. They may use these cavities to hibernate in during the winter as well. They also build leaf nests, a collection of leaves in the branches that are used by adults. They build the leaf nests high up in larger trees. They usually use large oak, elm, and other hardwood trees.
Females can mate with several males, but the males will compete with each other to determine who gets to mate first.
Fox squirrels can mate all year long; however, most mating occurs in two mating seasons on from December to February and another from May until June. Females can begin to have babies at 6 months old and have one or two litters per year. Males can begin to mate at 10 to 11 months old. Female fox squirrels are pregnant for about 44 days. Average litter size is 3 young but it can range from 1 to 6 young per litter.
Babies are born without fur and weigh 13 to 18 g. They develop fur after 14 days old. They open their eyes at about 30 days old. They begin to explore outside of the nest after about 7 to 8 weeks. They don't travel much on their own until 3 months of age.
Female fox squirrels care for their young in the nest for 6 weeks. When the mother leaves her young in the nest she covers them with nesting material. Young fox squirrels move away from their mothers in the fall of their first year. Male fox squirrels disperse farther and may die more as a result.
Fox squirrels have been known to live to 18 years old in captivity. Under natural conditions the average lifespan is 8 to 18 years old, though most squirrels die before they reach adulthood.
Fox squirrels spend most of their time in trees during the day. They live in small family groups whose home ranges overlap. They are not territorial but they will defend food and nest sources from neighboring squirrels.
Fox squirrels have excellent vision, even in dim light. They have well-developed senses of hearing and smell. Fox squirrels also have several sets of vibrissae. Vibrissae are thick hairs or whiskers that are used as touch receptors to sense the environment. These are found above and below their eyes, on their chin and nose, and on each forearm.
Fox squirrels communicate many ways. They use a variety of sounds, including barks, chatters, distress screams, and high-pitched whines. They use scent marks. They also communicate through behavior. For example, they will threaten one another by standing upright with their tail over their back and flicking it.
Fox squirrels are omnivores, eating everything from plant matter to insects, birds, and carrion. Their diet depends on what is available in the area in which they live. Fox squirrels mainly eat the nuts, flowers, and buds of oak trees and walnut, hickory, and pecan trees. They also eat fruits, seeds, and buds of maple trees, mulberry, hackberry, elms, buckeyes, horse chestnuts, wild cherries, dogwoods, hawthorn, hazelnut, ginkgo, and pine seeds. They eat edible varieties of fungus when they are available. They will eat bird eggs and nestlings, bones, and other small animals or animal remains as they find them. Squirrels are scatterhoarders, which means that they hide small amounts of food in various locations and go back to find it later. They find them later by remembering where they put them and by smelling for the food. They use their strong incisors to chew through the husks of the different kinds of seeds they eat. In the fall of each year fox squirrels begin eating much more than they need so that they can accumulate a large store of body fat to help them get through the winter. Fox squirrels can get some of the water they need from eating moist foods, but generally need to have standing water for drinking. They might find small pools of water that collect after rains in the holes and nooks of large trees. Female fox squirrels need foods with extra protein and calcium, such as bones, meat, and nuts, when they are pregnant and nursing their young.
Fox squirrels are preyed on mainly by large hawks and owls. Young squirrels may also be taken by snakes. Fox squirrels take advantage of their agility and maneuverability in the trees to escape most predators. They emit alarm calls that alert other squirrels when they see a predator.
Because squirrels eat so many tree seeds, they play a significant role in shaping the composition of forests. Together with other seed-eating animals, they may eat almost all of the tree seeds produced in some years. When squirrels bury seeds and forget them, these seeds are likely to sprout where they were placed. Because of this, squirrels promote the growth of certain kinds of trees. Fox squirrels are also important prey items for small predators because they are so abundant.
Some people think squirrels are a nuisance because they raid bird feeders and gardens. They sometimes damage corn crops. They often use electrical lines as routes of travel, and this can cause power outages.
Fox squirrels are hunted for food and for their fur, even though the fur is not very valuable. In addition, fox squirrels are important tree seed dispersers.
Several subspecies of fox squirrels in the eastern United States are endangered due to overhunting and destruction of forests.
Bridget Fahey (author), University of Michigan-Ann Arbor.
Koprowski, J. L. Sciurus niger. Mammalian species No. 479: 1-9.
Nowak, R.M. Walker's Mammals of the World, 5th Edition. Johns Hopkins University Press.