The Flying Squirrel

Did you know that there are flying squirrels here in New Jersey?  The first time I realized this, I was a little freaked out. I couldn't help but picture a rodent flying at my face. Then, I did some research. Turns out, flying squirrels are quite intriguing and their mechanisms for flight are really cool. Aspects of human inventions like the wingsuit and planes resemble the wings of flying squirrels. How could these creatures have evolved? Do they fly because they are related to birds?

A drawing of a flying squirrel (original photo)

What is a flying squirrel?

This incredibly fascinating creature illustrated above is known as the flying squirrel. It is a mammal and a rodent (not a bird). In the wild, they live on average five to six years. There are about 50 different species of flying squirrels in total. They can be as small as dwarf flying squirrels which are about 3 inches long and weigh about 3.5 ounces. These tiny gliding creatures are found in the Malay Peninsula and frequently get mistaken for large butterflies. They can also be as big as the Japanese giant flying squirrel which is about 2 feet long and weighs about 5 pounds. Flying squirrels can be found worldwide, but are mostly found in Asia. There are 2 species that are native to North America, the northern flying squirrel, and the southern flying squirrel. They are mainly found in forests or woodlands. If these animals are not related to birds, how did they develop the ability to fly?

A flying squirrel gliding to a nearby tree (original photo)

How do they fly?
Okay, so they can’t technically fly, they glide. They developed something called patagia, which produces lift and enables them to glide. A patagium is a special membrane made up of loose skin and underlying muscle that connects the front and back legs. When they spread their limbs apart, the membrane is exposed and the body is transformed into a gliding platform. They can use small leg movements to steer and they can use their tail as a break. They also have a small flap on their wings that curl upwards, similar to the tips of the wings on an airplane. These are theorized to help increase flight efficiency and help control the glide (as it does in commercial planes). A flying squirrel can glide as far as 450 meters (about 1476 feet).

Their ecological niche

Flying squirrels are nocturnal, meaning that they are awake when it is dark outside. For that reason, they can be hard to spot. If you would like to find a flying squirrel, they den in tree cavities and rock crevices. Flying squirrels are omnivores and their diet mostly consists of seeds, fruits, nuts, flower buds, insects, or spiders. Flying squirrels have to be careful of predators including snakes, owls, raccoons, and foxes.

A Flying squirrel on a tree (original image)

Their evolution

Flying squirrels make up the tribe Pteromyini within the squirrel subfamily Sciuridae. They are most closely related to the tree squirrel. Flying squirrels were found to have diverged from tree squirrels during the Oligocene Epoch about 33.9 million to 23 million years ago. Flying squirrels are frequently compared with sugar gliders. They both have big eyes, white bellies, and patagia, and they are both known for their ability to glide from tree to tree. However, flying squirrels are placental mammals and sugar gliders are marsupials. They are not very closely related at all as their most recent common ancestor is most likely a rat-like animal. In actuality, these animals are most likely the result of convergent evolution and their similarities are examples of analogous structures. They live very similar lifestyles. They both jump from trees, necessitating their patagia, and forage for food, leading to large eyes. The environment led to similar selective pressures and they evolved independently from one another.

A sugar glider (original image)

Some examples of adaptations that flying squirrels have developed are a good balance, intricate wrist bones (to help with steering), and fluffy tails to stabilize flight. Their ability to glide makes them very adept at escaping from predators. The adaptations that they have developed over time are part of why flying squirrels are so neat. They are one of a handful of mammals that have developed the ability to glide. Their ability to glide makes them very energy efficient. Since they are mostly active at night and are mostly found high in trees, they are rarely seen or noticed. Both southern and northern flying squirrels can be found in New Jersey, so next time you're walking at night, look up in the trees and see if you notice a flying squirrel.