Flying Squirrel

Pteromyini

Flying squirrels (tribe Pteromyini) are about 50 species of night-active squirrels that glide from tree to tree on a furry membrane stretched between the wrist and the ankle. They live in forests across North and Central America, Europe and Asia, from the 38–90 g southern flying squirrel to giant flying squirrels weighing well over 1 kg. Despite the name, they cannot truly fly: every glide starts high on one tree and ends lower on another.

Also known as Polatouche (French), Letyaga (Russian), Musasabi (Japanese, for the Japanese giant flying squirrel)

Flying squirrel abilities

up to 28 m southern flying squirrel glide
Climb high, leap, spread the legs, and the furry membranes turn the squirrel into a living kite that sails to the next trunk.
- Most southern flying squirrel glides are 6–9 m. The longest reach about 28 m.
- Red giant flying squirrels have been seen gliding up to 75 m.
- A glide always ends lower than it started. How far a squirrel goes depends mostly on how much height it drops.
- Gliders often take short, steep glides, even though longer, flatter ones would cost less energy per metre.
How far do they glide?
Southern: most glides6–9 m
Southern: longest28 m
Red giant: longest seen75 m
Distances from the species accounts on this page.
Sources [1, 9, 13, 16]
2 cartilage spurs, one per wrist
A stiff rod of cartilage flicks out from each wrist to hold out the front corner of the membrane, like the frame of a kite.
- The styliform cartilage is attached to a small wrist bone, the pisiform. It swings out when the wrist is bent back and outwards.
- Spread, it makes the gliding surface bigger. Folded, it keeps the membrane tucked away while the squirrel climbs.
- The wrist bones of flying squirrels are unlike those of any other gliding mammal.
- An 11.6-million-year-old fossil from Spain was first mistaken for a primate, until its tiny wrist bones showed it was a flying squirrel.
Sources [2, 8]
3–10× body weight on landing
Just before touching down, the squirrel tips its head and body up so the whole membrane catches the air and slows it down.
- In test jumps, northern flying squirrels landed with forces of 3–10 times their body weight.
- When the approach was too steep, they couldn’t pitch up enough and landed front paws first, taking bigger jolts.
- Scientists think the need for softer landings may be why gliding control evolved in flying squirrels in the first place.
- Malayan colugos, unrelated gliders, also turn their bodies before landing, and land more softly after longer glides.
Sources [13, 17]
Pink under ultraviolet lightStill debated
Shine an ultraviolet torch on a North American flying squirrel and its fur glows pink, on the back and the belly.
- Reported in 2019 from 109 museum skins and 5 wild squirrels, in males and females of every North American species, collected over 130 years.
- Day-active grey, fox and red squirrels did not glow.
- Nobody knows what it is for. Ideas include camouflage, a warning or mimicry. It may have no job at all: glowing fur turns up in at least 125 mammal species, mostly night-active ones.
- Night birds such as owls glow pink under UV too, from a pigment called coproporphyrin III.
Sources [2, 10, 11, 12, 18]
65 kHz peak of a recorded call
Flying squirrels chirp, trill and make short bursts of noise, and some of these calls are pitched far above what people can hear.
- Ultrasound means sounds above 20 kHz, the top of human hearing. Noise-burst calls often peaked above 60 kHz.
- Owls hear only up to about 12–14 kHz, so scientists wonder whether high calls let squirrels keep in touch without owls listening in. That idea is not yet tested.
- Humboldt’s flying squirrels use arc chirps, tonal chirps, upsweeps and trills, with more trills in summer, the breeding season.
- Gliding mammals in general seem to use ultrasound more than their non-gliding relatives.
How high is that?
Flying squirrel call peak65 kHz
Top of human hearing20 kHz
Top of barn owl hearing13.8 kHz
One recorded noise burst; many calls are lower and some you can hear.
Sources [2, 4, 19]
23 groups of fungi in autumn diet
Northern flying squirrels feast on truffles, the hidden underground fruit of fungi that partner with tree roots, and spread their spores.
- Droppings from 318 northern flying squirrels in eastern Washington held 23 genera or groups of fungi in autumn, plus about 22% plant material.
- The droppings held more kinds of truffle (19 genera) than the scientists found by searching the soil (12).
- Truffle spores can pass through a mammal’s gut alive, so truffle-eaters help these root fungi spread to new trees.
Sources [3, 14, 15]
25–40° angle of the twig fork
Some small Asian flying squirrels carve a groove around a nut and jam it into a forked twig, storing it like a carpenter’s joint.
- Filmed in Hainan, China, in two species of small Hylopetes flying squirrels.
- The twigs were only 0.1–0.6 cm thick and met at angles of 25–40°.
- The larders were 10–25 m from the nearest nut tree, which probably keeps other animals from finding them.
- Southern flying squirrels store food too. When stores run low, their spring breeding season can start later.
Sources [1, 5]
2–4 young in a northern litter
Mothers raise their tiny, hairless babies in tree holes or snug nests high above the ground.
- Northern flying squirrels nest 1–18 m up, in nests of twigs and bark lined with fur, feathers, leaves and needles.
- Southern flying squirrels use old woodpecker holes, bird and squirrel nests, and nest boxes. They can have two litters a year, of 1–7 young.
- A newborn southern flying squirrel weighs just 3–5 g.
- Up to 8 northern flying squirrels sometimes share one nest.
Sources [1, 3]

Tap a pin on the model or a part below.

31 days until a baby’s eyes open
- Big, dark eyes for the body’s size. In the southern flying squirrel they are ringed with black fur.
- Flying squirrels are the only squirrels alive today that are active at night.
- Before it jumps, a southern flying squirrel moves its head from side to side to judge the distance to its landing spot.
- Northern flying squirrel babies are born with their eyes shut. They open after about 31 days.
Sources [1, 2, 3]
>20 kHz some calls are ultrasonic
- Some flying squirrel calls are ultrasonic: higher than 20 kHz, the top of human hearing.
- Owls, which hunt at night, hear best between about 2 and 6 kHz and only up to about 12–14 kHz.
- A baby southern flying squirrel’s ears stay sealed for its first 3–4 weeks.
Sources [1, 4]
0.1–0.6 cm thin twigs used to hold nuts
- In a rainforest in Hainan, China, small flying squirrels chew a groove around a nut, then wedge it tightly into a forked twig.
- The groove fits the twig like a carpenter’s joint, so the nut hangs safely in the bushes.
- Northern flying squirrels eat nuts, acorns, fungi and lichens, plus fruit, buds, sap and the occasional insect or bird egg.
Sources [3, 5]
Wrist to ankle furry patagium
- Each side has a loose fold of furry skin, the patagium, running from the front wrist to the back ankle.
- Spreading the legs pulls it tight like a kite. In the southern flying squirrel its edge is lined with black hair; the Siberian flying squirrel’s has a soft fur fringe.
- Letting one side go a little slack changes the angle, speed and direction of the glide.
- In lab glides, southern flying squirrels tilted the membrane at 35–54° to the airflow, steep enough to make an aircraft wing stall, and came down at angles of 40–57°.
Sources [1, 6, 7]
11.6 million years age of the oldest wrist spurs found
- A rod of cartilage, the styliform cartilage, sticks out from each wrist and supports the outer edge of the membrane.
- It swings out when the squirrel bends its wrist back and outwards, making the membrane bigger.
- When the squirrel climbs, the wrist spur keeps the membrane tucked out of the way.
- This wrist set-up is found only in flying squirrels, and it was already there in a fossil 11.6 million years old.
Sources [2, 8]
≈80% of head-and-body length
- The northern flying squirrel’s tail is furry, flat and rounded at the tip, about 80% as long as its head and body.
- The red giant flying squirrel’s tail is about 42 cm long, longer than its 40 cm head and body.
- Many guides call the tail a rudder and brake. The studies we read describe steering mainly with the membranes, so the tail’s exact job is less well measured.
Sources [1, 3, 9]
Pink glow under UV light
- Under ultraviolet light, the fur of all North American flying squirrels glows pink, on the back and on the belly.
- Museum skins of day-active grey, fox and red squirrels did not glow.
- Glowing fur turns up in many night-active mammals, so the pink may come from pigments in the fur rather than a special signal.
Sources [10, 11, 12]
3–10× body weight on landing
- In short test jumps, northern flying squirrels pushed off with 1–10 times their body weight and landed with 3–10 times.
- Just before landing they tip the body up so the membrane acts like an air brake.
- On a steep approach they can’t pitch up enough, so they hit front paws first and take a harder jolt.
- On the ground, northern flying squirrels are clumsy compared with how gracefully they glide.
Sources [3, 13]
23 kinds of fungi in the autumn diet
- In eastern Washington, USA, the autumn diet of northern flying squirrels held 23 genera or groups of fungi, plus about 22% plant material.
- Most of those fungi were truffles: the hidden, underground fruiting bodies of fungi that live on tree roots.
- Truffle spores can survive the trip through a mammal’s gut. Living spores have been found in the droppings of at least 40 mammal species.
Sources [14, 15]

Real flying squirrels

Photos from Wikimedia Commons. Each one can repaint the 3D model as its species.

Southern flying squirrelSmall: 20–28.5 cm long including the tail and 38–90 g, with big dark eyes ringed in black and a membrane edged with black hair.IUCN: Least Concern. Often moves into nest boxes.Mid-glide: a southern flying squirrel with its patagium stretched tight. Photo: Pratikppf (English Wikipedia), CC BY-SA 3.0
Southern flying squirrelSmall: 20–28.5 cm long including the tail and 38–90 g, with big dark eyes ringed in black and a membrane edged with black hair.IUCN: Least Concern. Often moves into nest boxes.Southern flying squirrel in a red maple. Photo: Ken Thomas, Public domain
Southern flying squirrelSmall: 20–28.5 cm long including the tail and 38–90 g, with big dark eyes ringed in black and a membrane edged with black hair.IUCN: Least Concern. Often moves into nest boxes.Snacking on sunflower seeds at a bird feeder. Photo: Joshua Mayer, CC BY-SA 2.0
Northern flying squirrelBigger than its southern cousin: about 25–30 cm long and 70–140 g, with a flat, furry tail about 80% as long as its head and body.IUCN: Least Concern. The Carolina subspecies is listed as Endangered in the USA.Northern flying squirrel. Photo: Henrique Pacheco, CC BY 4.0
Northern flying squirrelBigger than its southern cousin: about 25–30 cm long and 70–140 g, with a flat, furry tail about 80% as long as its head and body.IUCN: Least Concern. The Carolina subspecies is listed as Endangered in the USA.Northern flying squirrel in Canada. Photo: Henrique Pacheco, CC BY 4.0
Siberian flying squirrelHead and body 12–23 cm and about 130 g on average, with a soft fringe of fur along the edge of the membrane.IUCN: Least Concern. Prefers forests with plenty of old, hollow trees.Siberian flying squirrel. Photo: Andrew Bazdyrev, CC BY 4.0
Siberian flying squirrelHead and body 12–23 cm and about 130 g on average, with a soft fringe of fur along the edge of the membrane.IUCN: Least Concern. Prefers forests with plenty of old, hollow trees.Siberian flying squirrel in mixed forest near Borovsk, Russia. Photo: Pavel Chekanov (Чеканов Павел), CC BY-SA 4.0
Giant flying squirrel (red giant)A heavyweight: the red giant flying squirrel averages about 1.75 kg, with a 40 cm head and body and an even longer 42 cm tail.Glides seen up to 75 m. Red, Japanese and Indian giant flying squirrels are all Least Concern.Red giant flying squirrel. Photo: Richard Fuller, CC0
Giant flying squirrel (red giant)A heavyweight: the red giant flying squirrel averages about 1.75 kg, with a 40 cm head and body and an even longer 42 cm tail.Glides seen up to 75 m. Red, Japanese and Indian giant flying squirrels are all Least Concern.Red giant flying squirrel, one of the biggest gliders. Photo: Kalyan Varma, CC BY 4.0
Giant flying squirrel (red giant)A heavyweight: the red giant flying squirrel averages about 1.75 kg, with a 40 cm head and body and an even longer 42 cm tail.Glides seen up to 75 m. Red, Japanese and Indian giant flying squirrels are all Least Concern.Japanese giant flying squirrel (musasabi), Karuizawa, Japan. Photo: Julia Wittmann, CC BY 4.0

Flying squirrel by the numbers

Measured by scientists and museums, with comparisons you can picture.

Species: 52; in 15 genera, across North America, Europe and Asia⁠[8]
Southern flying squirrel: 38–90 g; 20–28.5 cm long, tail included⁠[1]
Red giant flying squirrel: ≈1.75 kg; average weight; head and body ≈40 cm, tail ≈42 cm; About 19 times the heaviest southern flying squirrel⁠[9, 1]
Typical glide: 6–9 m; most southern flying squirrel glides⁠[1]
Longest glide seen: 75 m; red giant flying squirrel; southern flying squirrels reach about 28 m⁠[9, 1]; Red giant75 mSouthern28 m
Landing force: 3–10×; body weight, in short test jumps by northern flying squirrels⁠[13]
Highest call peak: 65 kHz; a recorded noise burst; ultrasound starts at 20 kHz⁠[4]; Flying squirrel call65 kHzTop of human hearing20 kHz
Pregnancy: 37–42 days; northern flying squirrel; about 40 days in the southern⁠[3, 1]
Newborn weight: 3–6 g; southern 3–5 g, northern 5–6 g; born hairless with eyes closed⁠[1, 3]
Lifespan: 3–5 years; southern flying squirrels in the wild; a northern flying squirrel has lived 13 years in captivity⁠[1, 3]

Flying squirrel myths and facts

Tap Myth or Fact for each claim, then check the answer.

0 of 8 answered

“Flying squirrels can fly like bats.”
“Flying squirrels flap their skin flaps to stay in the air.”
“Some flying squirrels glow pink under ultraviolet light.”
“Scientists have proven the pink glow helps flying squirrels hide from owls.”
“Flying squirrels only live in faraway tropical rainforests.”
“A sugar glider is a kind of flying squirrel.”
“Flying squirrels are out and about in the daytime, like other squirrels.”
“Flying squirrels make sounds too high for people to hear.”

Flying squirrel records

Superlatives and record holders, each checked against its source.

Most kinds of gliding mammal
52 species
Flying squirrels
the only group of gliding mammals with real diversity, in 15 genera⁠[8]
Oldest flying squirrel skeleton
11.6 million years
Miopetaurista neogrivensis
from Catalonia, Spain; first thought to be a primate, until its wrist bones turned up⁠[8]
Only night-shift squirrels
1 group
Flying squirrels
the only living squirrels that are active at night⁠[2]
Longest glide on this page
75 m
Red giant flying squirrel
an observed glide; southern flying squirrels manage about 28 m⁠[9, 1]
Biggest gliding membrane
Neck to tail tip
Colugo (Philippine flying lemur)
no other gliding mammal has such a big membrane; a flying squirrel’s runs from wrist to ankle⁠[26, 1]
Highest-pitched call on this page
65 kHz
Northern and southern flying squirrels
peak of a recorded noise burst, more than 3 times the top of human hearing⁠[4]
Tail longer than the body
≈42 cm
Red giant flying squirrel
tail, against a head and body of about 40 cm⁠[9]

A year in the life of a flying squirrel

Mostly the southern flying squirrel, which can raise two families a year.

Autumn
Filling the larder
Flying squirrels store food for later. When a southern flying squirrel’s stores run low, the spring breeding season can be delayed.⁠[1]
Through the year
Sharing a nest
Some squirrels share a home. Northern flying squirrels may live in groups of up to 8 adults and young.⁠[3]
February–March
Spring breeding
The first breeding season. In a New Hampshire study it ran from 11 February to 26 March.⁠[1]
About 40 days later
Tiny babies
After a pregnancy of about 40 days, the mother gives birth in a tree hole or nest. Spring litters usually have 2 or 3 hairless babies of 3–5 g each.⁠[1]
3–6 weeks old
Eyes open
Eyes and ears open at about 3–4 weeks. The babies are nursed until they are about 5–6 weeks old.⁠[1]
About 2 months old
First glides
In northern flying squirrels, the young are weaned at about 2 months and try their first glides around then.⁠[20, 3]
June–July
Second family
A second, summer breeding season for southern flying squirrels. Summer litters are often bigger, with 4–5 young.⁠[1]
3–5 years
A short life
Southern flying squirrels usually live 3–5 years in the wild.⁠[1]

Flying squirrel vs sugar glider vs colugo

Three unrelated animals that evolved the same trick: a furry gliding membrane and a life at night.

Flying squirrel vs sugar glider vs colugo
	Flying squirrel	Sugar glider	Colugo
What it is⁠[8, 25, 26]	A rodent: a squirrel	A marsupial	A colugo, also called a “flying lemur”
Where⁠[8, 1, 25, 17]	North and Central America, Europe and Asia	Eastern Australia	Southeast Asia
Size⁠[1, 9, 25, 17, 26]	38–90 g (southern) to ≈1.75 kg (red giant)	16–21 cm long	about 0.75–1.75 kg
Gliding membrane⁠[1, 8, 27, 26]	Wrist to ankle, held out by a cartilage spur on each wrist	Outer side of the front foot to the ankle	Neck to the tips of the fingers, toes and tail
Active⁠[2, 25]	At night	At night	At night

Gliding evolved separately in six living groups of mammals, and all of them are nocturnal.

Are flying squirrels endangered?

It depends on the species. The best-known flying squirrels are common, but some rare Asian species are in serious trouble.

IUCN Red List

Varies by species

Trend unknown

The southern, northern, Siberian and red giant flying squirrels are all Least Concern. The Namdapha flying squirrel is Critically Endangered and the western woolly flying squirrel is Endangered.⁠[22, 21, 23, 24, 28, 29]

IUCN Red List: each species is assessed separately

Threats

Losing old trees
Flying squirrels nest in tree holes. Siberian flying squirrels prefer forests with plenty of old, hollow trees.⁠[6, 1]
Logging and fire (past)
In the southern Appalachians, industrial logging and fires around 1900 badly shrank the high forests where Carolina northern flying squirrels live.⁠[20]
Tree-killing insects
Tiny insects called adelgids are killing Fraser firs and hemlocks in those same mountain forests.⁠[20]
Climate change
A warming climate could add more stress to cool, high mountain forests.⁠[20]

What’s helping

Legal protection1985
The Carolina northern flying squirrel has been listed as Endangered in the USA since 1 July 1985.⁠[20]
Replanting red spruce
Biologists are restoring red spruce in parts of the southern Appalachians to make up for lost conifers.⁠[20]
Nest boxes
Southern flying squirrels readily move into nest boxes as well as old woodpecker holes.⁠[1]
Keeping old trees
Leaving old, hollow trees standing keeps nest sites for species like the Siberian flying squirrel.⁠[6]

Status of some flying squirrels

Southern flying squirrelLeast Concern
Eastern North America to Central America.⁠[22, 1]
Northern flying squirrelLeast Concern
The species is Least Concern; its Carolina subspecies is Endangered under US law.⁠[21, 20]
Siberian flying squirrelLeast Concern
Northern Europe and Asia; depends on old, hollow trees.⁠[23, 6]
Red giant flying squirrelLeast Concern
One of the biggest flying squirrels, at about 1.75 kg.⁠[24, 9]
Western woolly flying squirrelEndangered
Endangered on the IUCN Red List.⁠[29]
Namdapha flying squirrelCritically Endangered
Critically Endangered on the IUCN Red List.⁠[28]

Flying squirrel quiz

12 questions. Every answer is somewhere on this page.

Question 1 of 12Score 0

Can flying squirrels truly fly?

Flying Squirrel field notes

Diet, food web, safety and badges from the Snappit field guide.

Diet & Feeding

These omnivores munch on nuts, seeds, fruits, fungi, and even insects.

Primary Foods

Acorns
Hickory nuts
Fungi
Berries
Insects
Lichen
Foraging Method: Foraging

Ecological connections

Great Horned OwlEaten by
A silent, nocturnal predator that hunts flying squirrels.
Long-tailed WeaselEaten by
A slender, agile hunter that can pursue squirrels into tree hollows.
Oregon TruffleEats
Helps disperse the spores of this underground fungus, aiding forest health.

Safety

Danger 1/5 · Very low

If you ever see a flying squirrel, admire them from a distance and don't try to catch them.

Traits

Collections

Mammals

Classification

Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Rodentia
Family: Sciuridae

Sources for these flying squirrel facts

29 studies and references · checked Oct 16, 2026

Frequently Asked Questions

How to identify Flying Squirrel?

Compare ears, muzzle, tail, feet and coat markings. Size is hard to judge without something nearby for scale, and young mammals may not have adult coloring yet. Mammal Identifier: upload a photo and compare the visible details.

How long is Flying Squirrel?

12-20 cm

What is Flying Squirrel's wingspan?

25-35 cm

How much does Flying Squirrel weigh?

0.05-0.15 kg

How long does Flying Squirrel live?

3-6 years

What does Flying Squirrel eat?

These omnivores munch on nuts, seeds, fruits, fungi, and even insects.

Where is Flying Squirrel usually found?

Forests

Can flying squirrels actually fly?

No. They glide. A flying squirrel climbs high, leaps and spreads its legs so the furry membrane between wrist and ankle pulls tight like a kite. Every glide ends lower than it started. Most southern flying squirrel glides are 6–9 m.

How far can a flying squirrel glide?

Southern flying squirrels usually glide 6–9 m and can manage about 28 m. Red giant flying squirrels have been seen gliding up to 75 m. The distance depends mostly on how much height the squirrel can drop.

Do flying squirrels glow in the dark?

Not on their own. But under an ultraviolet torch, the fur of North American flying squirrels glows pink. This was reported in 2019. Many other night-active mammals glow under UV too, and nobody knows yet whether the glow has a purpose.

Where do flying squirrels live?

There are 52 species across North America, Europe and Asia. The southern flying squirrel ranges from eastern North America to Honduras, the Siberian flying squirrel lives in the forests of northern Eurasia, and giant flying squirrels live in Asia.

What do flying squirrels eat?

Northern flying squirrels eat nuts, acorns, fungi and lichens, plus fruit, buds, sap and the occasional insect or bird egg. Truffles are a big part of their diet: one study found 23 groups of fungi in their autumn droppings.

Are flying squirrels nocturnal?

Yes. Flying squirrels are the only squirrels that are active at night, and every living gliding mammal is strictly nocturnal.

How big is a flying squirrel?

It depends on the species. A southern flying squirrel is 20–28.5 cm long including the tail and weighs 38–90 g. Northern flying squirrels weigh 70–140 g. The red giant flying squirrel averages about 1.75 kg.

Are flying squirrels endangered?

Most well-known species are not: the southern, northern, Siberian and red giant flying squirrels are Least Concern. But the Namdapha flying squirrel is Critically Endangered, the western woolly flying squirrel is Endangered, and the Carolina northern flying squirrel has been protected as Endangered in the USA since 1985.