Red Squirrel

Tamiasciurus hudsonicus

Last updated: May 15, 2023
Verified by: AZ Animals Staff
© Giedriius/Shutterstock.com

The red squirrel has one of the most impressive memories in the entire animal kingdom


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Red Squirrel Scientific Classification

Kingdom
Animalia
Phylum
Chordata
Class
Mammalia
Order
Rodentia
Family
Sciuridae
Genus
Tamiasciurus
Scientific Name
Tamiasciurus hudsonicus

Read our Complete Guide to Classification of Animals.

Red Squirrel Conservation Status

Red Squirrel Locations

Red Squirrel Locations

Red Squirrel Facts

Name Of Young
Kits or pups
Group Behavior
  • Solitary
Fun Fact
The red squirrel has one of the most impressive memories in the entire animal kingdom
Estimated Population Size
Unknown
Biggest Threat
Competition for resources with other animals
Most Distinctive Feature
The red-colored fur
Other Name(s)
Pine squirrel and chickaree
Gestation Period
1 month
Litter Size
1-8 pups
Habitat
Hardwood and conifer forests
Predators
Weasels, martens, minks, foxes, lynx, snakes, eagles, owls, and hawks
Diet
Omnivore
Favorite Food
Nuts, seeds, mushrooms, flowers, sap, insects, and bird eggs
Type
Mammal
Common Name
Red Squirrel
Number Of Species
1

Red Squirrel Physical Characteristics

Color
  • Brown
  • Grey
  • Red
  • White
Skin Type
Hair
Top Speed
15 mph
Lifespan
5 years on average
Weight
200-300g (7-10oz)
Length
25-38cm (10-15in)
Age of Sexual Maturity
1 year
Age of Weaning
70 days

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The American red squirrel is one of the most common mammals in all of North America.

As a type of rodent, these agile tree climbers are found almost anywhere with mixed hardwood and evergreen conifer forests. They’ve also adapted very well to urban and suburban environments. Renowned for their excellent memory, American red squirrels will bury their food for the winter and then return to it later to feed. While easily dismissed for their small size and ordinary appearance, they are actually quite remarkable creatures.

5 Incredible Red Squirrel Facts!

  • Red squirrels play an important environmental role by dispersing seeds and fungi throughout the ecosystem. After burying a cache of food, the squirrel sometimes forgets about it or fails to return, leaving the seed germinating.
  • One of the more amazing facts is that squirrels can remember the location of thousands of nuts they buried during their preparation for the lean winter months. Their brain even seems to expand in size and develop more neural activity during the fall.
  • The squirrel’s big, bushy tail is not just for show. It helps to provide balance and regulate body temperature.
  • Another amazing fact is that squirrels have a remarkable ability to jump vertically some 4 to 5 feet and horizontally around 10 feet. Like cats, they seem to land on their feet without any problem by twisting their bodies in the air and rotating their tail.
  • There are 25 recognized subspecies of American red squirrels, isolated by region.

Scientific Name

American Red Squirrel - Tamiasciurus hudsonicus, closeup of squirrel peeking out of a small hole in a tree trunk. Bokeh of leaves in the background.

The American red squirrel is a separate species in a different genus from the Eurasian red squirrel.

©RT Images/Shutterstock.com

The scientific name of the American red squirrel is Tamiasciurus hudsonicus. It was named after Hudson Bay, where it was first cataloged in 1771. Its closest living relatives in the genus of Tamiasciurus are the Douglas squirrel and Mearns’s squirrel, both of which have a more grey-brown body color. The American red squirrel should not be confused with the Eurasian red squirrel, which is a separate species in a different genus.

Species

The American red squirrel is one of three tree squirrel species in the genus Tamiasciurus, also called the pine squirrel. The others are the Douglass squirrel, (T. douglasii), and the southwestern red squirrel, (T. fremonti). More names for the American red squirrel are the Hudson’s Bay squirrel and chickaree.



There are 23 subspecies of American red squirrels listed at the end of the article.

Evolution

Eastern gray squirrel tracks in snow

Squirrels crossed the Bering Strait land bridge to cross from North America to Europe around 30 million years ago.

©Susan Edmondson/Shutterstock.com

The earliest fossil evidence of squirrels was found in western North America and dated to around 36 million years ago. Six million years later – fossil records indicate that squirrels appeared in Europe. During that time the Bering Strait land bridge provided passage for many different species – including squirrels – from North America. Squirrels show up in African fossil records shortly after they collided with Eurasia about 18 – 20 million years ago. After that, squirrels evolved and adapted to their diverse environments – into the over 200 species known today.

Appearance

squirrel eating acorns

American red squirrels are rusty red with white bellies.

©iStock.com/suefeldberg

The red squirrel can be identified by its small but stout body, relatively large paws, bushy and curling tail, and erect ears with small tufts of fur. Their long incisors, which help them cut through tough material, can grow 6 inches in a year and must be worn down by eating and gnawing. The back and face are covered with a rusty red color that turns slightly grey in the winter, while the underside of the body and the ring around the eyes are white. There are also black parts around the tail and nose.

Red squirrels are about the same size as a large book. They weigh between 7 and 10 ounces and measure about 10 to 15 inches with the tail included. Both males and females are similar in appearance.

Red Squirrel vs. Grey Squirrel

Grey squirrels can be as much as 50% larger than red squirrels.

©Sterling E Thompson/Shutterstock.com

In North America, there are several species of grey squirrel, including the eastern grey squirrel, the western grey squirrel, the Arizona grey squirrel, and the Mexican grey squirrel, all of which belong to a separate genus, Sciurus. Besides the obvious differences in color, the red squirrel is about 30% to 50% smaller than other types of tree squirrels. It also has tufts of fur on the ears and lacks the multi-colored “halo” effect around the tail.

Behavior

Red squirrel collecting food in the forest.

The American red squirrel can remember where it hid food for up to two years.

©Henk Bogaard/Shutterstock.com

The American red squirrel is a true expert at foraging for limited resources. The peak of their activity occurs in the fall when they prepare to stock up on food for the winter. The squirrel will bury thousands of different nuts every year in random underground caches around its territory. In order to find where they hid the food, the squirrel must rely on its excellent memory. Some studies performed on a similar grey squirrel demonstrate that they can still recall the solution of a puzzle two years after first learning about it.

For a small number of squirrels, the arduous process of nut collection may be too much work. They will spy on other squirrels that bury their food and then resort to outright theft. This competition for food may be a matter of life and death since the winter can be harsh and unforgiving. As the temperature drops, the squirrel becomes progressively more lethargic and inactive. It does not quite enter a state of hibernation, however, since it will leave the nest to forage and eat at least once a day.

Red squirrels are highly territorial in nature and do not tolerate the presence of intruders. Each one maintains a territory a few acres in size. Their aggression tends to ramp up in the fall as they prepare for the mating season and the lean winter months. Squirrels will construct their nests somewhere within their territory and close to the food caches.

Eastern gray squirrel nest
Squirrels build nests in trees if there is no natural hollow or cavity available.

They prefer to inhabit the natural hollows and cavities of trees, but if these are not available, then they will usually build a nest in branches, underground burrows, and even human homes and buildings. They are very discriminating in their choice of homes. Tree diameter, the structure of the branch, and the existence of escape routes are all factored in. The nests will be lined with grasses, moss, feathers, leaves, and fur.

In order to communicate, the red squirrel makes a cacophony of different chirping, growling, screeching, and buzzing sounds. Most of these sounds serve as a warning against predators, threats, or anything else that encroaches on its territory. The sounds also help aggressive males drive off reproductive competitors in the breeding season.

A scent marking will be the first sign that the squirrel is intruding on someone else’s territory. This will usually be enough to drive away intruders and prevent unnecessary conflicts. But if these incursions persist, then a fight may break out among the squirrels.

Habitat

View of a mountain lake between fir trees

The red squirrel prefers a habitat of mixed hardwood-conifer forests.

©iStock.com/Oleg Charykov

The red squirrel can be found almost anywhere in Canada and the United States (including Alaska) with plenty of coniferous tree cover. This means it’s much less common in the Great Plains states, the southeastern US, and parts of the Pacific coast. It seems to prefer a habitat of mixed hardwood-conifer forests with spruce, pine, hemlock, or fir trees in elevations of up to 2,500 feet.

Predators and Threats

Barred Owl in flight, hunting for prey during the winter in northern Wisconsin.

Red squirrels are a favorite food for owls and other birds of prey.

©Lynn_Bystrom/Shutterstock.com

Many red squirrels will die to predation and natural attrition yearly, but this species does not face any significant threats in the wild. Habitat loss is generally not a problem on the whole. While squirrels may lose some territory to logging and development, the amount of tree cover has remained steady in the United States. Perhaps the biggest problem is that red squirrels are sometimes outcompeted for resources, especially by their larger and bulkier grey cousins.

What eats the red squirrel?

The red squirrel is preyed upon by weasels, martens, minks, foxes, lynxes, snakes, eagles, owls, and hawks. Humans have historically hunted them for food and for their fur.

Diet

What does the red squirrel eat?

The red squirrel primarily feeds on seeds and nuts. These highly opportunistic animals will supplement their diet with the occasional piece of fruit, mushrooms, tree sap, flowers, insects, or bird eggs. In order to draw out the tree sap, the squirrel will puncture the sap-carrying vessels and then harvest it later. But it will only resort to this if other food is not widely available. The green seeds of conifer trees appear to be the squirrel’s favorite type of food.

Reproduction and Life Cycle

Baby squirrels, a type of rodent, looking out for their mother.

Baby squirrels are expected to be fully independent around 70 days after they are born.

©Nilanka Sampath/Shutterstock.com

The red squirrel has one or two defined breeding seasons per year, usually lasting between March and May and between August and September. Males compete against each other quite aggressively to acquire the most mates. Individual pair bonding is rare. The female may only be in estrus (meaning sexually available) for one day every breeding season. In this short window, the males will spend their energy pursuing the female and driving off other competitors.

After a pregnancy period lasting about a month, the female gives birth to an average of four (though as many as eight) young at a time. These baby pups are born completely helpless and without much fur. The mother assumes sole responsibility for raising the young, while the male usually returns to his own territory and has no other contact with the mate and the offspring.

Lactation occurs within the first 70 days of birth. After each baby is weaned off the milk, the pups are expected to become fully independent. Sometimes, when the mother is ailing, the newly mature squirrel may receive some pieces of her territory, like the heirs to an estate. This will significantly increase their odds of survival.

Little baby red squirrel sitting on a log.

Red squirrels have a high birth rate and a high youth mortality rate.

©Miroslav Hlavko/Shutterstock.com

Red squirrels have a very high birth rate, probably because they also have a very high youth mortality rate as a baby due to predation, lack of food, and harsh environmental conditions. Only about a quarter of them will survive their first year of life. If they do grow out of the juvenile phase, however, they will have a lifespan of about five years. The oldest squirrel on record lived about 10 years in the wild.

Population

The American red squirrel is currently classified as a species of least concern by the IUCN Red List. While population numbers are not well-known, this species probably numbers in the millions. However, this obscures some variability in the population numbers of some local subspecies. The Mount Graham red squirrel of Arizona, for instance, is known to be endangered with only a few hundred individuals remaining in the wild.

List of the 23 Subspecies of American Red Squirrel

1. T. h. abieticola13. T.h. lychnuchus
2. T.h. baileyi14. T.h. minnesota
3. T. h. columbiensis15. T.h. pallescens
4. T.h. dakotenisi16. T.h. petulans
5. T.h. dixiensis17. T.h. picatus
6. T.h. fremonti18. T.h. preblei
7. T.h. gymnicus19. T.h. regalis
8. T.h. kenaiensis20. T.h. richardsoni
9. T.h. lanuginosus21. T.h. streatori
10. T.h. laurentianus22. T.h. ungavensis
11. T.h. loquax23. T.h.ventorum
12. T.h. lychnuchus

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About the Author

After a career of working to provide opportunities for local communities to experience and create art, I am enjoying having time to write about two of my favorite things - nature and animals. Half of my life is spent outdoors, usually with my husband and sweet little fourteen year old dog. We love to take walks by the lake and take photos of the animals we meet including: otters, ospreys, Canadian geese, ducks and nesting bald eagles. I also enjoy reading, discovering books to add to my library, collecting and playing vinyl, and listening to my son's music.

Red Squirrel FAQs (Frequently Asked Questions) 

Are red squirrels endangered?

No, the red squirrel is a species of least concern – the best possible classification. However, some individual subspecies may be endangered.

Where do red squirrels live?

The American red squirrel can be found in hardwood or coniferous tree cover all over the United States and Canada.

How rare is a red squirrel?

The red squirrel is one of the most common mammals in North America.

Is the red squirrel extinct?

No, red squirrels are still thriving just about everywhere they can be found.

Do grey squirrels kill red squirrels?

Grey squirrels do not usually kill red squirrels directly, but they will sometimes out-compete red squirrels for resources or even pass on dangerous viruses and pathogens.

Why are red squirrels bad?

Red squirrels aren’t really bad, but they can sometimes have a negative impact on the local ecosystem by stripping off bark and flowers from trees. This can prevent trees from fully growing properly. The squirrels can also cause property damage with their very sharp teeth and claws. While this behavior can be very annoying to people, they do this to sharpen their incisors.

What do red squirrels eat?

The red squirrel mostly consumes nuts and seeds. This is supplemented with fruit, mushrooms, flowers, sap, insects, and bird eggs.

How did the red squirrel evolve?

While the exact origin of the red squirrel is not well-understood, the first squirrel ancestors evolved around 45 to 57 million years ago. They later diversified into tree and ground squirrels some 25 million years ago.

What are the differences between the red squirrel and the chipmunk?

The main differences between red squirrels and chipmunks are that red squirrels are larger, are granivores, and mostly live in Canada and the Rocky Mountains. Chipmunks are smaller, are omnivores, and live across North America and Asia.

What are the differences between the red squirrel and the fox squirrel?

Fox squirrels and red squirrels differ in size, distribution, and habitat preferences.

Thank you for reading! Have some feedback for us? Contact the AZ Animals editorial team.

Sources
  1. Animal Diversity Web, Available here: https://animaldiversity.org/accounts/Tamiasciurus_hudsonicus/
  2. Connecticut DEEP, Available here: https://portal.ct.gov/DEEP/Wildlife/Fact-Sheets/Red-Squirrel

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