The northern flying squirrel (Glaucomys sabrinus) is a small nocturnal mammal known for its ability to glide between trees. Although it is called a flying squirrel, it does not truly fly but instead glides using a special membrane of skin stretched between its legs. This squirrel lives mainly in the forests of North America, especially in cooler northern regions. With its large eyes, soft fur, and gliding ability, the northern flying squirrel is uniquely adapted to life in dense woodland habitats.
What Is a Northern Flying Squirrel?
Scientific Classification
The northern flying squirrel belongs to the squirrel family Sciuridae, which includes tree squirrels, ground squirrels, and flying squirrels. Its scientific name is Glaucomys sabrinus.
Basic classification:
- Kingdom: Animalia
- Phylum: Chordata
- Class: Mammalia
- Order: Rodentia
- Family: Sciuridae
- Genus: Glaucomys
- Species: Glaucomys sabrinus
This species is one of the two main flying squirrel species found in North America, the other being the southern flying squirrel.
Overview of the Species
The northern flying squirrel is a nocturnal gliding mammal that spends most of its life in trees. Unlike typical tree squirrels that run and jump along branches, this species can glide from one tree to another.
Because it is active mainly at night, it is rarely seen by people during the day. Its large eyes allow it to see well in low-light conditions while moving through the forest.
These squirrels are well adapted to cold forest environments, especially in northern regions and mountainous areas.
Why It Is Called a Flying Squirrel
The northern flying squirrel does not truly fly like birds or bats. Instead, it glides through the air using a thin flap of skin called the patagium.
This membrane stretches between the squirrel’s front and back legs. When the squirrel jumps from a tree, it spreads its limbs and the patagium forms a gliding surface.
Gliding helps the squirrel:
- Move efficiently between trees
- Escape predators
- Search for food across larger areas
In some cases, northern flying squirrels can glide up to 150 feet (45 meters) depending on the height of the tree.
Northern Flying Squirrel Physical Characteristics
Northern flying squirrels have several physical features that help them glide, climb, and survive in forest habitats. Their bodies are lightweight and well suited for life in trees.
Size and Body Structure
Northern flying squirrels are relatively small compared to many other squirrel species.
Typical measurements include:
- Body length: 9–11 inches (23–28 cm) including the tail
- Tail length: About 3–5 inches (8–13 cm)
- Weight: Around 2–5 ounces (60–140 grams)
Their small body size helps them glide more easily between trees.
Fur Color and Appearance
Northern flying squirrels have soft, thick fur that helps keep them warm in colder climates.
Their fur is usually:
- Gray-brown on the back
- Pale gray or white on the belly
- Soft and dense for insulation
This coloring helps them blend into tree bark and forest surroundings.
Key Identification Features
Several distinctive traits make northern flying squirrels easy to recognize.
Important features include:
- Patagium membrane between the legs for gliding
- Large dark eyes for excellent night vision
- Flat bushy tail used for steering during glides
- Sharp claws that help them climb trees
- Lightweight body suited for gliding
These adaptations make the northern flying squirrel highly efficient at moving through forest canopies.
Northern Flying Squirrel Habitat
Geographic Range
Northern flying squirrels are found across large parts of North America, particularly in cooler northern regions.
Their range includes:
- Much of Canada
- The northern United States
- Mountain forests in the western United States
They are especially common in areas with large, mature forests.
Preferred Environment
Northern flying squirrels prefer dense forests with tall, mature trees. These forests provide both food sources and safe nesting areas.
Common habitats include:
- Coniferous forests
- Mixed hardwood and conifer forests
- Mountain forests
- Old-growth woodland areas
Trees such as spruce, fir, pine, and hemlock are often important parts of their habitat.
Nesting Locations
Northern flying squirrels typically live in tree cavities, which provide protection from predators and harsh weather.
They often use:
- Natural holes in trees
- Abandoned woodpecker nests
- Hollow logs
Sometimes they also build nests made from:
- Leaves
- Moss
- Bark
- Twigs
These nests provide shelter and a safe place for raising young. During winter, several northern flying squirrels may share a nest together to stay warm.
Northern Flying Squirrel Diet
Main Foods
The northern flying squirrel has a varied omnivorous diet, but it relies heavily on fungi found in forest ecosystems. These squirrels play an important role in spreading fungal spores, which help trees grow and maintain healthy forests.
Common foods include:
- Mushrooms and underground fungi
- Lichens
- Nuts and seeds
- Berries and fruits
- Tree buds and plant material
Fungi are often the most important part of their diet, especially in mature forests where these food sources are abundant.
Occasional Animal Foods
Although most of their diet is plant-based, northern flying squirrels sometimes eat small animal foods.
These may include:
- Insects
- Beetles and larvae
- Bird eggs
- Small invertebrates
Eating a variety of foods helps them survive when certain food sources become scarce.
Seasonal Diet Changes
The northern flying squirrel’s diet changes throughout the year depending on available foods.
Spring:
They eat tree buds, young plant shoots, and insects.
Summer:
Berries, fruits, seeds, and fungi become more common.
Fall:
They gather nuts, seeds, and fungi in preparation for winter.
Winter:
They continue feeding on stored food and fungi that remain available under snow or in tree cavities.
Northern Flying Squirrel Behavior
Nocturnal Activity
Northern flying squirrels are nocturnal animals, meaning they are active mainly at night. During the daytime, they remain hidden in tree cavities or nests.
Their large eyes allow them to see well in the dark, helping them search for food and move through the forest safely.
Gliding Ability
One of the most remarkable abilities of the northern flying squirrel is its gliding movement between trees.
When the squirrel jumps from a tree, it spreads its legs and stretches the patagium membrane. This creates a gliding surface that allows it to travel through the air.
Some important facts about their gliding ability include:
- They can glide distances of up to 150 feet (45 meters).
- Their tail helps control direction while gliding.
- They can land precisely on tree trunks.
Gliding helps them move efficiently through forests without coming down to the ground often.
Social Behavior
Northern flying squirrels can be more social than many other squirrel species. In colder seasons, several squirrels may share the same nest.
Group nesting helps them:
- Stay warm during winter
- Reduce energy loss
- Increase survival in cold climates
However, they usually search for food individually.
Northern Flying Squirrel Lifespan
Lifespan in the Wild
In natural environments, northern flying squirrels usually live about 4 to 6 years. Many individuals face dangers such as predators and harsh weather that can shorten their lifespan.
Lifespan in Captivity
In captivity, where food and protection are provided, northern flying squirrels may live up to 10 years or more.
Factors Affecting Lifespan
Several factors influence how long these squirrels live:
- Predator presence
- Food availability
- Weather conditions
- Habitat quality
- Disease and parasites
Northern Flying Squirrel vs Southern Flying Squirrel
Size Differences
Northern flying squirrels are generally slightly larger than southern flying squirrels and have thicker fur suited for colder climates.
Habitat Differences
Northern flying squirrels prefer cooler northern forests and mountain regions, while southern flying squirrels are more common in warmer eastern and southern forests.
Behavior and Diet Differences
Northern flying squirrels depend more heavily on fungi in their diet, while southern flying squirrels tend to eat more nuts and fruits.
Interesting Northern Flying Squirrel Facts
They Can Glide Long Distances
Northern flying squirrels can glide more than 150 feet between trees, allowing them to move efficiently through forests.
Large Eyes for Night Vision
Their large dark eyes are specially adapted for seeing in low-light conditions, helping them stay active at night.
Important for Fungi Dispersal
These squirrels help spread fungal spores through their droppings, which helps forests maintain healthy soil and tree growth.
Rarely Seen by Humans
Because they are nocturnal and live high in trees, northern flying squirrels are rarely seen by people during the day.
Predators and Threats
Natural Predators
Northern flying squirrels face several predators in the wild.
Common predators include:
- Owls
- Hawks
- Snakes
- Martens
- Foxes
Owls are one of their biggest threats because both animals are active at night.
Environmental Threats
Human activities can also affect northern flying squirrel populations.
Major threats include:
- Deforestation
- Habitat fragmentation
- Climate change
- Loss of mature forest habitats
Importance in the Ecosystem
Fungi Spore Dispersal
Northern flying squirrels play an important role in spreading fungal spores throughout forests. These fungi help trees absorb nutrients from the soil.
Supporting Forest Biodiversity
By helping fungi grow and spreading plant seeds, northern flying squirrels contribute to healthy forest ecosystems and biodiversity.
Conclusion
The northern flying squirrel is a fascinating nocturnal mammal known for its gliding ability and life in forest canopies. Found across northern North America, this small squirrel has specialized adaptations that allow it to glide between trees, find food at night, and survive in cold forest environments. With its important role in spreading fungi and supporting forest ecosystems, the northern flying squirrel remains a valuable and unique part of North American wildlife.
