How Did The Fox Squirrel Arrive In The Eastern United States?how-did-the-fox-squirrel-arrive-in-eastern-unisted-states

Besides its name, there are many other interesting facts about the fox squirrel, including its morphology, color phase, and nesting habits. This article will explore each of these factors and answer the question, “How did the fox squirrel arrive in the eastern United States?”


For phylogeographic studies of eastern North America, the fox squirrel is an excellent candidate. These rodents occur throughout most of eastern North America, east of the Rocky Mountains, at latitudes up to 48degN. Although they are widespread, some subspecies are threatened or endangered, mainly because of habitat destruction. In this article, we will discuss some of the evolutionary and genetic differences between eastern and western fox squirrels.

The MC1R24 haplotype is associated with melanism in both the gray and fox squirrel species, suggesting that they shared a common ancestor. It is unlikely that the two species evolved independently, because balancing selection would likely have retained the haplotype. However, it is possible that mutations in different haplotypes may have arisen independently. This mutation in the MC1 gene may have been an introgression.

Habitat preferences

Among the many species of squirrels that inhabit eastern North America, the eastern fox squirrel has diverse habitat preferences. It is found in cypress domes and upland pine forest. These habitats provide year-round nest trees and year-round food sources such as pine seeds and cabbage palm. It also has sparse understories and low/volatile temperatures that favor breeding.

The fox’s diet consists of a variety of nuts that are immature or mature. It also feeds on a variety of plants, including trees, bushes, and fruit. These animals dig holes in lawns and gardens and bury their food. Sometimes they will gnaw telephone cables and wood buildings. However, despite being nocturnal, these animals can cause considerable damage.

Nesting habits

The Eastern Fox Squirrel is a diurnal, non-territorial rodent that spends much of its day on the ground compared to other tree squirrels. It uses a variety of materials in its nests, including suet, corn, and tree bark. These animals use two types of dens: leaf nests, which are built in crotches of tree branches, and hollowed-out tree trunks. Typically, breeding pairs use two dens for their young, and their nests are co-habitable. Their homes are usually located at least fifteen feet up in trees.

The nesting habits of the Eastern Fox Squirrel have been studied since the late 1970s, and have shown that it relies on ample supplies of potential den cavities to raise a family. In fact, it takes thirty to forty pounds of hard mast to support one squirrel for a breeding season. If the hard mast does not grow quickly enough, the subadult class will be forced out of its home range, which has a negative effect on recruitment and population stability.


The fox squirrel is a medium-sized tree squirrel with no sexual dimorphism. Females have eight digits and a well-furred tail, while males are slightly larger and possess abdominal musculature. Females mate with several males at once, and males compete to mate first. Polygamy and the origin of the fox squirrel are still debated topics, but the species’ reproductive practices are generally viewed as an evolutionary benefit.

The Eastern fox squirrel, Sciurus niger, is the largest representative of its group in North America. It is divided into 10 subspecies, including red-tailed and gray-headed ones. Its range is primarily in the eastern and central United States, with some subspecies having spread into the southern and northern prairies of Canada, some parts of Mexico, and urban areas in western U.S.

Reproductive biology

A study by Claytor and Moncrief (2011) revealed that the fox squirrel has distinct ovarian characteristics based on age and reproductive category. Females in estrus had more tertiary follicles than nonreproductive ones, while the corpora lutea was present in 100 percent of pregnant and lactating fox squirrels. Interestingly, the fox squirrels have a much shorter gestation period than the other squirrel species, making their gestation period shorter than other mammals.

The gestation period of the fox squirrel is 44 days, with litter sizes varying from two to four young. The female’s body mass accounts for twenty percent of her body weight during this period. The young are ten to fifteen grams in weight, and females give birth to multiple litters a year. Males typically move on after the female gives birth and don’t mate with the females until at least a year after they give birth.

Range expansion

During the last decade, scientists have gathered enough evidence to estimate the extent of fox squirrel population loss in eastern North America. A study of the southeastern United States suggests that populations of S. niger have declined. They are present along the Arkansas River and its major tributaries, but there are no known evidences to suggest that the population has expanded into southeastern New Mexico.

Moncrief and colleagues (1998) studied fox squirrel populations in the lower Mississippi River valley and found that the morphological variation between western and eastern species did not match allozymic differences. In addition, the authors hypothesized that there are two refugia in the eastern United States. In addition, they documented distinct east-west patterns of allozymic differences among eastern and western populations. These findings are consistent with their model of fox squirrel range expansion in the eastern United States.


What colors can fox squirrels be?


Gray brown or black.


Where do fox squirrels live?


In North and Central America.


How big are fox squirrels?


They can be up to 3 feet long.


How do fox squirrels travel?


They can climb and jump.


What do fox squirrels eat?


They eat insects acorns nuts fruits and seeds.


What is the predators of fox squirrels?


Owls snakes and hawks.


How long do fox squirrels live?


In the wild they can live up to 10 years old.


How much does a fox squirrel weigh?


Between 1 and 2 pounds.


When are fox squirrels most active?


In the morning and the evening.


What is the home range of a fox squirrel?


1 to 2 acres.


How many young does a fox squirrel have at a time?


2 to 5.


What is the gestation period of a fox squirrel?


45 days.


When do fox squirrels mate?


In the winter.


How did the fox squirrel arrive in the Eastern United States?


They were introduced in the early 1900s.


What is the scientific name for the fox squirrel?


Sciurus niger

How Did The Fox Squirrel Arrive In Eastern Unisted States

Jessica Watson is a PHD holder from the University of Washington. She studied behavior and interaction between squirrels and has presented her research in several wildlife conferences including TWS Annual Conference in Winnipeg.

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