CRITTERS OF NORTH IDAHO: Flying squirrel soaring in North Idaho
It’s a bird! It’s a plane! Actually, it’s neither of those (nor is it Superman). It’s actually a small mammal gliding in from the forests of northern Idaho: Glaucomys sabrinus, otherwise known as the northern flying squirrel.
Animals have a variety of methods they use to become airborne. We say that a creature is capable of true flight when it is capable of producing lift to elevate itself. Birds do this using wings composed of feathers extending from their hands and arms. The wing of a bat consists of skin stretched across its entire front limb. The wing of a pterosaur (“pterodactyl”) is similar, but the membranous skin is stretched between an elongated finger bone, along its arm and to its leg. Insect wings are extra appendages that look like miniature stained glass windows. Once in the air, it is common for those capable of true flight to flap to retain their position, or even fly higher.
The flying squirrel, on the other hand, is a little bit different. Their “wings” are actually flaps of skin stretched between their front and back limbs called “patagium”, and they are only capable of gliding. But glide they do, brilliantly! The flaps of skin along the sides of their bodies act kind of like a parachute, slowing their descent long enough to steer and end up exactly where they want to go. To quote a well-known space-ranger Buzz Lightyear, “This isn’t flying. It’s falling … with style!”
One thing that helps the flying squirrel remain airborne is its small size. They’re 10 to 13.5 inches long and weigh between 75 and 140 grams, making them quite light. You can usually see the squirrel’s patagium even when not extended, making these rodents quite easy to identify. If you’re still stumped, however, take notice that the squirrel is grayish brown in color with a pale underbelly. Another thing to keep in mind if you’re looking for flying squirrels is that they’re mainly active at night. This is because they’re not quite agile enough to dodge airborne predators like birds of prey, and the patagium renders them clumsy on the ground, making them easy prey for weasels, coyotes and domestic cats. The darkness conceals them while they go about their nightly activities.
What is it that northern flying squirrels get into at night anyway? Usually they’re on the lookout for food. Like most squirrels, flying squirrels love acorns and other nuts, but they’ll also munch on fungi, lichens, fruit, bird’s eggs and insects on occasion. It is believed that they stash their food for later, like other squirrels, but this has never been observed. Fortunately for the flying squirrels, all of aforementioned foods are common in the coniferous (pine tree) forests in which they live, but they’ve got to consume considerable quantities of them in order to sustain their rapid metabolism.
This is where gliding comes in handy! Instead of climbing up a tree, snacking on some acorns, and then climbing back down the tree to repeat the whole process, the flying squirrel saves time by climbing up a tall tree and then leaping off, spreading their patagium to slow their descent. But wait! The squirrel’s gliding off in the wrong direction! Not to worry. Their long fluffy tail acts as a rudder, steering them whichever way they want to go next.
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