Flying Squirrel

Quick Take

• Flying squirrels can glide an almost unbelievable distance, one so impressive that it puts a famous landmark to shame. See gliding details →
• Their genes have barely changed in tens of millions of years, and the reason why reveals something clever about survival. Explore their ancient lineage →
• A highway in North Carolina posed a life-or-death problem for flying squirrels, and the fix that was found is stranger than you would expect. Discover the PVC pipe fix →
• These squirrels store enough food in a single season to feed a small army, yet their nightly diet is far more varied than nuts alone. See their varied diet →

Despite its name, a flying squirrel doesn’t fly the same way a bird or a bat flies. Instead, flying squirrels glide or drift through the air. These omnivores eat insects, mushrooms, flowers, and, of course, nuts. Flying squirrels are nocturnal animals and search for food at night. They can change direction by 180 degrees when gliding through the air.

Incredible Flying Squirrel Facts

• These squirrels can gather and store up to 15,000 nuts in one season.
• The 50+ types of flying squirrels are in a group known to scientists as Pteromyini.
• The extremely large eyes of these small rodents allow light to pour in so they can see at night.
• These squirrels live in Europe, Asia, North America, Mexico, and Central America.

Evolution

Biologists believe that flying squirrels first began to diverge from the family tree of regular squirrels and develop their signature gliding ability sometime between 23 and 36 million years ago. Their genes have remained largely unchanged since they first appeared on the evolutionary scene, as their special gliding membrane has proven to be an incredibly successful trait for escaping predators and securing food with ease. Flying squirrels are also notable to biologists for being the most diverse lineage of gliding mammals alive today, with more than 60 gliding mammal species soaring through forests across Asia, Europe, and North America.

Classification and Scientific Name

Flying squirrels belong to the Sciuridae family and the Mammalia class.

The southern flying squirrel, the northern flying squirrel, Humboldt’s flying squirrel, and the Japanese dwarf flying squirrel are just four of the over 50 species of this animal in the Pteromyini tribe.

Appearance and Behavior

These squirrels have a light coat of brown fur on their back and white fur on their stomach. Some types of squirrels have small differences in fur color. For instance, the southern flying squirrel has all-white fur on its stomach while a northern flying squirrel has belly fur that’s white at the tip and darker near the skin. The most notable feature of all of these squirrels is a pair of large, dark eyes. Their eyes let a lot of light in, which helps these animals to see their surroundings as they hunt at night.

These squirrels have a flat tail, four small feet, and long whiskers. Their whiskers help them to avoid running into objects while hunting at night. Like their cousin, the ground squirrel, they have sharp teeth they use to cut into black walnuts and other types of nuts.

Adult flying squirrels have a total body length of up to 12 inches, with southern flying squirrels measuring about 8 to 10 inches and northern flying squirrels measuring 10 to 12 inches. They weigh from three to five ounces. For reference, a 14-inch-long squirrel is almost as long as a bowling pin. Furthermore, a squirrel that weighs eight ounces is as big as an adult hamster.

The largest species is the Red and White Giant flying squirrel. It has a body length of up to about 21.6 inches with a tail measuring around 24 inches. Also, this squirrel weighs around 6.6 pounds. In contrast, the Japanese dwarf flying squirrel is one of the smallest types of these squirrels. It grows to be around nine and a half to thirteen inches long, including its tail, and weighs between five and eight ounces.

These squirrels have a membrane or fold of skin called a patagium. This membrane spreads out on both sides of the squirrel’s body, allowing it to glide between tree branches. If you look up at a flying squirrel moving from tree to tree, the membrane takes the shape of a square.

Though these squirrels can glide a distance of up to 300 feet, the average gliding distance is 20 to 30 feet. To get a better mental picture, when a flying squirrel glides 300 feet, it is traveling about as far as the Statue of Liberty is tall (not including its base)! A squirrel that glides 65 feet is traveling a distance equal to the length of three adult giraffes.

These squirrels spend most of their time in trees as a way to stay safe from predators. When they do walk on the ground, they are clumsy and will hide from predators rather than trying to run away.

Adult and young squirrels share nests with about eight other squirrels. These small squirrels are not aggressive and are rarely seen, mostly because they are active late at night.

Habitat

These squirrels live in Europe, Asia, North America, Mexico, and Central America. They live in deciduous and coniferous forests high up in the trees. A group of these squirrels may live in a nest abandoned by a large bird or in a woodpecker’s hole in a tree. These squirrels stay in trees most of the time because they are more vulnerable to predators when they go to ground level.

These squirrels communicate with one another by letting out high-pitched chirping sounds as they glide through the trees. These chirps can be used to warn other flying squirrels of danger or to recognize members of a group. This is a quality they share with ground squirrels, which have a complicated system of chirps and barks they use to communicate with one another.

Northern, Southern, and all other species of flying squirrels like to stay warm. So, if the weather gets very cold in winter, they survive by huddling with other squirrels inside a tree or nest to keep warm.

Diet

What do these squirrels eat? These animals are omnivores and eat insects, flowers, bird eggs, nuts, fungi, and fruit. They have a varied diet and will eat whatever food source is most plentiful within their habitat.

A flying squirrel eats about 10 grams of food per day. This amount of food weighs a little less than an AAA battery you may put in an alarm clock.

Predators and Threats

It probably won’t surprise you to know that these squirrels have many predators. Some of them include snakes, owls, hawks, weasels, raccoons, bobcats, and sometimes even domesticated cats.

Most of this animal’s predators live in or can climb into trees. This makes flying squirrels vulnerable to them. Plus, many of these animals are nocturnal, so they are active at the same time. When looking for food, a raccoon may climb a tree to access a nest of these squirrels. Or, an owl may swoop down to capture a flying squirrel that has just taken off to glide toward another tree branch.

Humans are another threat to these squirrels because these animals are sometimes captured to sell as pets. Flying squirrels also face loss of their habitat whenever parts of a forest are cleared, and trees are cut down.

Though their habitat is threatened, there are some things people do to help flying squirrels. For example, when the Cherohala Highway was built in North Carolina, it was discovered that the highway was too wide for the northern flying squirrels to glide over. So, pieces of PVC pipe were attached to the top of poles on both sides of this highway. A squirrel gliding over this highway is able to safely grab onto the PVC pipe when it reaches the other side. They sometimes even disappear inside the PVC pipe for protection against predators in the area.

Reproduction, Babies, and Lifespan

During mating season, male squirrels chase females through the trees playfully. These squirrels breed twice a year. Breeding season happens from January through April and again from June through August. A male and female stay together for that breeding season and may not meet again. The gestation period, or pregnancy, lasts for 40 days.

A female squirrel gives live birth and can have up to six babies in a litter. However, most females only have two to three babies in one litter. A baby squirrel is about 2½ inches long from nose to tail tip — about the length of an adult human’s thumb.

Baby squirrels are called kits and are nursed by their mother in the nest for the first 65 days of life. They are born without fur, and their eyes and ears are closed. This makes them very vulnerable to larger animals that might find the nest. So, the mother stays with them except when she leaves to hunt food for herself. When they are about three or four days old, the kits’ ears open; at 25 days old, their eyes open. The kits stay with their mother in the nest until they are four months old. At that time, they are able to find their own food and can survive on their own.

In the wild, these squirrels live to be five or six years old. In a zoo or wildlife park, these squirrels can live to be 10 years old. These animals live longer in a zoo or wildlife park because they are protected from predators, fed nutritious food regularly, and cared for by staff.

In 2018, the oldest fossil of a flying squirrel was discovered in Catalonia, Spain, by paleontologists. The fossil is believed to be 11.63 million years old.

Population

When it comes to population, some types of flying squirrels are categorized as decreasing or stable, or their population trends are unknown. For instance, the Sipora flying squirrel in Indonesia is decreasing, while the population of the Indochinese flying squirrel in China is stable.

Sometimes scientists face challenges gathering the data they need to determine the population of a particular species of flying squirrel because some types of flying squirrels live in forests and wooded areas that are hard for humans to get to. Also, a group of flying squirrels may remain hidden, making it difficult for scientists to get an accurate count. One example is the Red-cheeked flying squirrel. There is not enough data to determine its population.