Flying squirrels are fascinating creatures.
They are members of the tribe Pteromyini in the family Sciuridae.
There are 44 species of flying squirrels.
Three species are North American, two live in northern Eurasia, and all others are found in the temperate and tropical forests of India and Asia.
The lifespan of a flying squirrel is about 6 years in the wild and up to 15 years in captivity.
Some giant flying squirrels of tropical India and southeastern Asia weigh 1 to 2.5 kilograms (2.2 to 5.5 pounds) and have a body length of about 30 to 60 centimeters (12 to 24 inches) and a tail 35 to 64 centimeters long.
The smallest are the dwarf flying squirrels (Petaurillus) of northern Borneo and the Malay Peninsula; their bodies are just 7 to 9 cm long and their tails 6 to 10 cm. When seen in the tall trees of the tropical rainforest, the glides of these tiny rodents are easily mistaken for the flutter of large butterflies.
Generally, flying squirrels have predominantly gray and brown coats, with generally white underparts, though they vary from species to species.
Despite the name, none use powered flight: all are gliders.
They glide the aid of a patagium, a furry, parachute-like membrane that stretches from wrist to ankle. When not in use, the membranes are pulled close to the body.
Flying squirrels can glide up to 90 meters (300 feet), steering with their tail, and landing on tree trunks, gripping it with all four feet.
They can make 180-degree turns while gliding.
Gliding is an energetically efficient way to progress from one tree to another while foraging, as opposed to climbing down trees and maneuvering on the ground floor or executing dangerous leaps in the air.
Unlike other squirrels, flying squirrels are nocturnal. They can easily forage for food in the night, given their highly developed sense of smell.
Flying squirrels are omnivores. They eat mostly plants, like seeds, nuts, leaves, maple sap, bulbs, bark, flowers, and roots. Less often, they eat insects, eggs, worms, small birds, and other small animals.
They den in tree cavities, grottoes or rock crevices on cliffs, and cave ledges.
The mating season for flying squirrels is during February and March. The young are born in a nest and are at first naked and helpless. They are cared for by their mother and by five weeks are able to practice gliding skills so that by ten weeks they are ready to leave the nest.
Flying squirrels are not dangerous and pose no health hazard. They’re not aggressive but they do have sharp teeth.
Some captive-bred southern flying squirrels have become domesticated as small household pets, a type of “pocket pet.”
In 2019 it was observed, by chance, that a flying squirrel fluoresced pink. Subsequent research by Paula Spaeth Anich, a biologist at Northland College in Northern Wisconsin, found that this is true for all three species of North American flying squirrels. At this time it is unknown what purpose this serves. Non-flying squirrels do not fluoresce under UV light.
Before the 21st century, the evolutionary history of the flying squirrel was often debated. This debate was clarified by two recent molecular studies. These studies found that the living flying squirrels originated 18–20 million years ago, are monophyletic, and have a sister relationship with tree squirrels.