Today is the last of my Inktober-inspired blog posts (side note: I finished Inktober, and drew 31 drawings in 31 days! Hooray!). The theme on day 28 was ‘fall’ and for some reason it made me think of flying squirrels. After all, gliding is really just a form of controlled falling.
There are 45 species of flying squirrel, making up the taxonomic tribe known as Pteromyini. There are other gliding mammals, such as the colugos, and the families Petauridae (which are marsupials) and Anomaluridae, which are not closely related to flying squirrels (though they are often called flying squirrels). True flying squirrels can be found in many places, including North America, Europe and Asia. Most flying squirrels are nocturnal, to avoid daytime predators such as birds of prey that could pick them off while the squirrels are gliding.
Flying squirrels are not only closely related to tree squirrels, they look pretty similar as well. There are few differences; flying squirrels have longer limbs, and shorter hands and feet than tree squirrels. These adaptations are all related to flyings squirrels’ primary method of locomotion: gliding.
All species of flying squirrel have a membrane-like structure running from their wrists to their ankles. This is known as a patagium, and allows flying squirrels to glide for up to 90 meters. Flying squirrels have exceptional control over their direction and movements during glides, thanks to special adaptations in their wrists. By moving their wrists while gliding, the squirrels adjust the position of the patagium, and thus control their direction of travel. Their long tails also help control direction during glides, and act as an air brake to help soften then impact of landing.
We’re not exactly sure why flying squirrels glide and tree squirrels simply leap around. One theory is that gliding is much more energy efficient than leaping around or crawling from tree to tree. Gliding also helps flying squirrels avoid predators, as they can simply glide away if they are threatened.
Another interesting hypothesis is that sudden leaps to avoid danger cause lots of strain on a squirrel’s body, especially during take off and landing. Gliding allows squirrels to be more precise and slow down before landing to minimize the impact on their bodies. Whatever the reason flying squirrels developed the ability to glide, it’s a pretty cool way of getting around.
Flying squirrels mate between February and March, with female flying squirrels nesting with their young while they develop. The young are born hairless and rely completely on their mothers for food and care. After about five weeks the young are almost fully developed, and start practicing jumping and gliding. At two and a half months of age, the young squirrels are ready to venture out on their own. They have to be careful though — flying squirrels fall victim to snakes, raccoons, owls, martens, fishers, coyotes, bobcats and owls, and young squirrels are particularly vulnerable to predation.
Flying squirrels are super cool! We should appreciate them more.
Cover image by lonelyshrimp, CC0, via Wikimedia Commons