Endemic to North America, the Eastern fox squirrel is a comparatively large rodent with a long and bushy tail. The scientific name of this species is 'niger' (black), since the first Eastern fox squirrel to be described had black coat. However, overall, the coloration of their fur varies greatly from individual to individual. The Eastern fox squirrel is co called due to the common yellowish-red coloration, closely resembling that of a fox. The Eastern fox squirrels also come in melanistic or entirely black coloration, which is more common in populations in the southern parts of their range. Individuals of both sexes look alike. The winter and summer coats are generally similar, although during the winter months, they exhibit more tufted ears as well as heavily furred foot soles. One of the most unusual facts about this mammal is that it has pink bones, whereas bones on most mammals are white. This is due to accumulating a chemical in its teeth, bones and tissues.
The natural range of this species extends over certain portions of southern Canada, eastern United States and northern Mexico. Meanwhile, introduced populations of the Eastern fox squirrel occur in British Columbia and Ontario (Canada) as well as California and Washington in the western part of US. The preferred habitat of this rodent is open woodland with open understory and scattered cover of trees. Within this habitat, the Eastern fox squirrel favors living among oaks, hickories, walnuts and pines. This animal is also known to occur in hedgerows and timbered fencerows that are adjacent to prairies. This type of habitat is also found in urban areas, where the Eastern fox squirrel can occasionally be observed.
The Eastern fox squirrels are mainly terrestrial, although they can also live in trees. These rodents are generally not very social animals. However, there have been known cases of several individuals living in the same nest during the winter months. Each individual has its own territory, which often overlaps with these of conspecifics. Females and their offspring are known to fiercely defend the central parts of their range. These animals are diurnal foragers that are active throughout the year. They usually nest in a tree called dreys. Nests are used as daily shelters and sites of raising the offspring. They construct their nest out of leaves and occasionally nest in tree cavities, especially during the winter. The major forms of communication are scents, vocalizations as well as tail and body postures. Vocalization includes a wide variety of barks. They typically use a chattering sound as an alarm call, whereas a tooth chattering serves as a display of aggression.
The Eastern fox squirrels are omnivores, they generally feed upon plant matter and gall insects, including moths, beetles, bird, eggs, and dead fish. They complement this diet with seeds such as these if acorn, hickory, walnut, mulberry, and Hawthorne.
The Eastern fox squirrels have a polygynandrous (promiscuous) mating system, where individuals of both sexes have multiple mates. However, males usually compete for their mating right. These rodents have two defined breeding season, one of which occurs in December-February, and the other lasts from May to June. Gestation period lasts for 44 - 45 days, yielding a litter of up to 7 young with an average of 2 - 3. Females are able to produce 2 litters per year, but generally yield only a single litter. Newborn babies are naked and cared by their mothers for the first 7 - 8 weeks of their lives, during which period they live in the nest. Leaving the nest, the female covers her offspring with nesting material. Complete weaning occurs at 12 - 14 weeks old, but the young become fully independent only at 16 weeks old. The age of sexual maturity is 10 - 11 months old for males and 8 months of age for females.
Currently, this species is threatened with loss of its natural habitat that results in sharp population decline. Thus, population in certain parts of Florida suffers from excessive logging of their pine forest habitat as well as development such as urbanization. On the other hand, their habitat is now becoming less favorable due to prevention of fires, which cause overgrowth of understory vegetation. And finally, this rodent is commonly hunted across the United States as a popular game species.
According to IUCN, the Eastern fox squirrel is abundant and widely distributed but no overall population estimate is available. Currently, this species is classified as Least Concern (LC) and its numbers remain stable.
On one hand, feeding on a wide variety of seeds, the Eastern fox squirrels have a huge impact on the ecosystem of their range, helping many plants survive. This is largely due to their habit of storing food items: burying seeds underground, they often forget them. As a result, many of these seeds consequently sprout. One the other hand, because of being common and widespread throughout their range, these animals are a key prey species for a number of small predators.