Eight Facts About The Flying Squirrel

Flying squirrels — which actually glide, not fly — date back to at least the Oligocene Epoch, and now come in 43 species across Asia, Europe, and North America. They sail from tree to tree on a special membrane between each front and back limb, a trick that has evolved multiple times in history. (Aside from flying squirrels, it’s also used by other aerial mammals such as anomalures, colugos, and sugar gliders.)

1. Those Adorable Eyes Are for Night Vision

Big, round eyes are one reason why flying squirrels look so cute to humans. But while this trait typically indicates infancy in mammals — like the wide eyes that endear us to babies and puppies — flying squirrels retain their disproportionately plump peepers into adulthood. They evolved big eyes to collect more light for better night vision, an adaptation shared by many nocturnal animals, from owls to lemurs.

2. They Can Glow at Night

While we know all species of flying squirrels are active at night, it wasn’t until recently that researchers discovered some also glow at night. They also learned the flying squirrels glow more strongly on their undersides. It’s still unclear why the squirrels give off a fluorescent effect at all, but the researchers have several theories, including avoidance of predators at night, communication among the squirrels, and navigation of snowy and icy terrain.

3. Instead of Wings, Flying Squirrels Have ‘Patagia’ and Wrist Spurs

The furry, parachute-like membrane between a flying squirrel’s front and back limbs is known as a “patagium” (the plural is patagia). These flaps catch air as the squirrel falls, letting it propel itself forward instead of plummeting. But to make sure the patagia catch enough air, flying squirrels also have another trick up their sleeves: cartilage spurs at each wrist that can be extended almost like an extra finger, stretching out the patagia farther than the squirrel’s tiny arms could on their own.

When a flying squirrel wants to reach a tree that’s beyond jumping distance, it just boldly leaps out into the night, as captured in the video above. It then extends its limbs, including its wrist spurs, to stretch out its patagia and start gliding. It lands on the trunk of its target tree, gripping the bark with its claws, and often immediately scurries to the other side to avoid any owls that might have seen its glide.

4. Flying Squirrels Can Glide 300 Feet and Make 180-Degree Turns

They may not really fly, but flying squirrels still cover impressive distances in the air. The average glide of a northern flying squirrel (Glaucomys sabrinusis) is about 65 feet (20 meters), according to the University of Michigan Museum of Zoology, or slightly longer than a bowling lane. But it can also go much farther if needed, with glides recorded up to 295 feet (90 meters). That means an 11-inch (28 cm) northern flying squirrel could glide almost the full length of a soccer field, or about as far as the Statue of Liberty is tall. It’s also remarkably agile, using its limbs, fluffy tail, and patagia muscles to make sharp turns, even pulling off full semi-circles in a single glide.

5. 90% of All Flying Squirrel Species Exist Only in Asia

Wild flying squirrels can be found on three continents, but they aren’t evenly distributed. Forty of 43 known species are endemic to Asia, meaning they naturally exist nowhere else on Earth. And relatives of flying squirrels have inhabited parts of Asia for roughly 160 million years, according to research on flying-mammal fossils that hail from the age of dinosaurs.

6. Only 3 Flying Squirrels Are Native to the Americas

Flying squirrels exist across a large swath of North and Central America, except for sparsely treed places like deserts, grasslands, and tundra. They’ve adapted to a wide range of forests in dramatically different climates, from Honduras to Quebec and Florida to Alaska. Yet unlike their highly diverse relatives in Asia, all these American flying squirrels hail from just three species. There’s the northern flying squirrel and the southern flying squirrel (Glaucomys volans), plus the Humboldt’s flying squirrel (Glaucomys oregonensis), identified as a species in 2017 after previously being classified as a subspecies of northern flying squirrel.

7. Baby Flying Squirrels Need a Lot of Mothering

Southern flying squirrels are savvy survivors, but they only get to that point with a lot of motherly love. Their ears open within two to six days of birth, and they develop some fur after about a week. Their eyes don’t open for at least three weeks, though, and they remain dependent on their mothers for several months. “Females care for their young in the nest and nurse them for 65 days, which is an unusually long time for an animal of this size,” the UMMZ adds. “The young become independent by 4 months old unless they are born later in the summer, in which case they usually overwinter as a family.”

8. Flying Squirrels Don’t Hibernate, but They Do Hygge

Despite inhabiting frigid forests in places like Canada, Finland, and Siberia, flying squirrels don’t hibernate. Instead, they become less active in cold weather, spending more time in their nests and less time foraging. (They do still venture out during winter, though, like the Japanese dwarf flying squirrels in the video above.) They’re also known to deal with harsh winter weather by huddling together. Multiple squirrels sometimes share a nest for this reason, beyond just immediate family members.  They can reduce their metabolic rate and body temperature to save energy.

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