Nepedia
Back to Discover
Advanced Reader
🧬

Eastern gray squirrel

life science Maturity 5-7 Next article →

The eastern gray squirrel, known scientifically as *Sciurus carolinensis*, is a highly adaptable tree squirrel.

Brown Squirrel 0300 (4327562105)
Brown Squirrel 0300 (4327562105)

It is a vital part of its native ecosystem in eastern North America. These squirrels act as natural forest regenerators. They do this by hiding seeds that eventually grow into new trees. However, when moved to new areas, they can become problematic. In Europe, they are classified as an invasive species. This means they can crowd out local wildlife. Because of this, the European Union prohibits their import or intentional release.

Eastern Grey Squirrel in Bunhill Fields
Eastern Grey Squirrel in Bunhill Fields

This species is native to the eastern and midwestern United States. It also lives in southern parts of Canada, such as Ontario and Quebec. In the mid-1800s, their numbers in the midwest were described as astonishing. Later, human activities like deforestation caused their numbers to drop significantly. By 1900, they were almost gone from Illinois. Today, their range extends from New Brunswick down to Florida and East Texas. They sometimes overlap with the fox squirrel, *Sciurus niger*. You can tell them apart because gray squirrels have white undersides.

Sciurus carolinensis Tracks
Sciurus carolinensis Tracks

The eastern gray squirrel has several unique physical traits. Most have gray fur with brown streaks and a bushy tail. Some squirrels possess a melanistic form, which means they are almost entirely black. This color comes from a mutation of the MC1R gene.

Juvenile sciurus carolinensis 1 (cropped)
Juvenile sciurus carolinensis 1 (cropped)

This dark fur helps them survive in cold climates. When exposed to -10 °C, black squirrels show an 18% reduction in heat loss. They also show an 11% increase in non-shivering thermogenesis, which is a way to create body heat. Adult squirrels vary in weight and size, but they do not show sexual dimorphism. This means males and females look very similar.

Growth and development follow a specific sequence for these animals. Newborns are called kits, kittens, or pups. They are born pink, hairless, and blind. Their skin begins to darken about 7 to 10 days after birth. Their lower incisors erupt between 19 and 21 days. Their eyes usually open between 21 and 42 days. By week 6, their cheek teeth begin to emerge. Weaning typically finishes by week 10. A squirrel will reach its full adult body mass by 8 to 9 months of age.

Juvenile sciurus carolinensis 1 (cropped)
Juvenile sciurus carolinensis 1 (cropped)

Squirrels use complex behaviors to survive and find food. They are scatter-hoarders, meaning they hide food in many small caches. An individual squirrel might make several thousand caches in one season. They use landmarks and a strong sense of smell to find them. They even use deceptive behaviors to trick rivals. A squirrel might pretend to bury an object while actually hiding it in its mouth. This suggests they may possess a "theory of mind," which is a type of advanced thinking.

Sciurus carolinensis -British Columbia, Canada-8
Sciurus carolinensis -British Columbia, Canada-8

Their physical abilities allow them to navigate trees with ease. They are among the few mammals that can descend a tree head-first. They achieve this by rotating their hind feet. This allows their claws to grip the bark as they move downward. For shelter, they build nests called dreys.

Squirrels drey
Squirrels drey

These spherical nests are made of twigs and leaves. They often add moss, feathers, or grass for insulation. Squirrels may also live in tree hollows or even in the walls of houses.

Gray Squirrel Window Drey
Gray Squirrel Window Drey

Finally, it is important to understand the health risks and history of the species. The fossil record shows they have existed in North America at least 18 times during the Pleistocene epoch. They can also carry various diseases and parasites. Ticks carried by squirrels can spread Lyme disease or Rocky Mountain spotted fever. They can also suffer from illnesses like squirrelpox or fibromatosis, which causes large skin tumors. While they are essential to North American forests, their presence in places like Vancouver Island or Britain can threaten native species like the American red squirrel or the Eurasian red squirrel.

630 words

Where will your curiosity go next?

Keep exploring at your chosen reading level.

🖼️ Images & Media (11)
Grey Squirrel (Sciurus carolinensis)...
File:Brown Squirrel 0300 (4327562105).jpg
Brown Squirrel 0300 (4327562105).jpg
File:Sciurus carolinensis Tracks.jpg
Sciurus carolinensis Tracks.jpg
File:Juvenile sciurus carolinensis 1 (cropped).jpg
Juvenile sciurus carolinensis 1 (cropped).jpg
File:Sciurus carolinensis -British Columbia, Canada-8.jpg
Sciurus carolinensis -British Columbia,...
File:Gray Squirrel Window Drey.jpg
Gray Squirrel Window Drey.jpg
File:Squirrels drey.JPG
Squirrels drey.JPG
File:Eastern Gray Squirrels (Sciurus carolinensis), Family - Mississauga 02.jpg
Eastern Gray Squirrels (Sciurus...
File:Hazelnuts gnawed by Grey Squirrel.jpg
Hazelnuts gnawed by Grey Squirrel.jpg
File:Eastern Grey Squirrel in Bunhill Fields.jpg
Eastern Grey Squirrel in Bunhill Fields.jpg
File:Problems at Dodd Wood (19534706210).jpg
Problems at Dodd Wood (19534706210).jpg
More to explore

🔬 Go deeper

More advanced topics to explore

🪜 Step back

Simpler topics to build understanding

What is Nepedia?

A free, ad-free encyclopedia for children. Every article is written at five reading levels, so the same page works for a five-year-old and a fifteen-year-old — use the level switcher above to see this one change. No account needed to read.