North American Squirrels

Image of eastern gray squirrel climbing tree

Squirrel Description

In the rodent family, squirrels are small, furry mammals known for their big, bushy tails and their propensity to store nuts for winter. There are three main varieties of squirrel types; tree, soil, and flying squirrels, although regionally common species differ.

These pests generally range in length from 12 to 25 inches and have short fur that varies in color, such as brown, red, black, and grey. Some have stripes, light-colored fur on their bellies, or even change their coats depending on the season.

Learn More: Pest Species In The U.S.

Size Of Common Squirrels

The average length of North American Squirrels:

  • Grey Squirrel: 55 cm
  • Red Squirrel: 45 cm
  • Fox Squirrel: 33 cm
  • Flying Squirrel: 22 cm

The average Weight of North America Squirrels:

  • Grey Squirrel: 1 lbs.
  • Red Squirrel: 0.75 lbs.
  • Fox Squirrel: 1.8 lbs.
  • Flying Squirrel: 1 lbs.

Squirrel Behavior

Photo of squirrel eating out of bird feeder

Gray squirrels are best described as a crepuscular species active in the spring, summer, and fall but are only active in winter around noon. In fall, when nuts are abundant, they may be particularly active. They are not territorial, but the squirrels will defend the immediate area around a nest site.

Gray squirrels have become accustomed to human interaction and often live in large, mature shade trees in urban or suburban areas.

During the day, Red squirrels are active but can rest during periods of the intense midday heat. They may remain inactive in their nests during severe winter weather. Juvenile red squirrels will establish their home sites near their mother. They have been known to be territorial and to defend their nesting areas from other red squirrels. 1Go To Source mass.gov -“Learn about squirrels”

Social Hierarchy Of Squirrels

Hierarchies define the relationships between squirrels living in close proximity to each other. Older, larger adult males dominate smaller males. Except when litter is present, females are subordinate to males. Females defend small territories around their dens or nests at this time.

Both sexes’ home ranges overlap, with the males’ being larger. The home range size depends on the availability of food, but generally is 1-6 acres. Adults are promiscuous and do not form bonds with couples. The only social groupings are female-young associations that may persist into winter.

Squirrel Communication Methods

Squirrels rely on vocal signals and produce many kinds of vocalizations to communicate. Females give kuks, quas, and moans before and after mating. These may be accompanied by foot-stamping and tail-waiving. Visual signals include posturing and motor patterns that are always important components of tail-position, movement, and form. Anal glands provide sexual status clues and perhaps other data as well. 2Go To Source esf.edu -“Gray Squirrel (Sciurus carolinensis Ord)”

Squirrel Reproduction

Females squirrels with birth live young after mating. At the age of one year, they are able to begin the mating process. In late winter, the first mating season begins, usually around the end of February. The season may last as long as May.

At the end of spring, the second mating season occurs and lasts until late summer. There are two litters for most squirrel species; one at the end of spring and one at the end of summer. Some species only have one litter once a year. Baby squirrels are referred to as kittens.

Squirrel Mating Process

Female squirrels produce a powerful scent that can be detected by the male squirrel. Once the male squirrel senses the female scent, he will chase her through trees at high speeds. He’ll also loudly slap the bark of the tree with his paws. If more than one male chases one female, the males will often try to chase each other away. It results in extraordinary acrobatics through the trees.

The female will select the strongest male with whom to mate. From that day forward, she will recognize him and never mate with him again. The male squirrel leaves after mating for good. He has nothing to do with the kittens being raised. 3Go To Source sciencing.com -“How Does a Squirrel Reproduce?”

Habitats That Attract Squirrels

In wooded areas, tree squirrels usually live since they prefer to live in trees. Ground squirrels are living up to their names. They dig burrows, a system of underground tunnels, to live in. To keep warm, some squirrels also hibernate in caves during the winter.

Flying squirrels often live on tree branches and crooks of trees. They will spread their muscle membrane and jump from trees to take flight (glide). Up to 160 feet, they can glide, making it look like they can fly. 4Go To Source livescience.com -“Squirrels: Diet, Habits & Other Facts”

Squirrel Species Range

With the exception of Madagascar, Australia, southern South America, the Antarctic, Greenland, many oceanic islands, and certain desert regions such as the Sahara, squirrels are found worldwide, originating in all terrestrial areas.

North American forest is filled with various squirrel species, and trees in all U.S. neighborhoods can be a suitable home for most squirrels.

Diet Of Common Squirrels

Picture of squirrel eating nuts

The majority of squirrels eat tree seeds and fruit mainly, but their diet is varied, including insects, eggs, fungi, lichens, and tiny vertebrates. Although some squirrels consume fungi as a secondary component of their diet, almost half of other species’ diet is made up of them.

Many squirrel species are opportunistic eaters and like the young and eggs of birds or other mammals. In general, foods such as buds, shoots, flowers, bark, lichens, and green plant material per unit weight have low energy content and make up a smaller portion of the diet.

Food availability and accessibility primarily determine the quantity of each type of food that is consumed. Diet composition changes from region to region, season to season, and year to year for this reason. Many squirrel species will also store or hoard food. 5Go To Source animaldiversity.org -“Sciuridae squirrels”

Predators Of The Squirrel

The list of squirrel-eating animals is long and depends on where squirrels live and the squirrel type. Common predators include:

  • Snakes
  • Martens
  • Hawks
  • Badgers
  • Eagles
  • Minks
  • Raccoons
  • Owls
  • Skunks

Squirrel Interaction With Humans

Squirrels are seen as pests, but not nearly as many other urban animals species. The common conflicts between humans and squirrels include invading attics and feeding on bird feeders. Once in an attic, these small rodents can cause severe damage to the building’s structure and insulation.

These critters have historically been eaten in many cultures, and a number of different recipes call for squirrel meat. The native red squirrels are outcompeting the invasive grey squirrels in the United Kingdom. A push to eat grey squirrel meat has been enacted to combat this and save the red squirrel. 6Go To Source animals.net -“Squirrel”

Squirrel Species

 

Sources:

  1. Commonwealth of Massachusetts. “Learn about Squirrels.” Mass.Gov, Commonwealth of Massachusetts, www.mass.gov/service-details/learn-about-squirrels. Accessed 22 Jan. 2021.
  2. Communications, Esf Office Of. “Gray Squirrel | Adirondack Ecological Center | SUNY ESF | College of Environmental Science and Forestry.” SUNY College Of Environmental Science And Forestry, State University of New York, 1988, www.esf.edu/aec/adks/mammals/gray_squirrel.htm#:%7E:text=Social%20system%20%2D%20Hierarchies%20define%20the,except%20when%20litters%20are%20present.&text=Home%20ranges%20of%20both%20sexes%20overlap%2C%20the%20males%20being%20larger.
  3. Nix, Ruth. “Squirrel Mating and Gestation.” Sciencing, Leaf Group Ltd./Leaf Group Media, 2 Mar. 2019, sciencing.com/squirrel-mating-gestation-8740132.html.
  4. Brown, E.; A. Peri and N. Santarosa 2014. “Sciuridae” (On-line), Animal Diversity Web. Accessed January 22, 2021 at https://animaldiversity.org/accounts/Sciuridae/
  5. Oldham, Cydni. “Squirrel.” Animals Network, Animals.NET, 18 July 2018, animals.net/squirrel.