What nocturnal rodent uses a membrane called a patagium to glide between trees?

The nocturnal rodent that uses a membrane called a patagium to glide between trees is the flying squirrel. This furry fold of skin stretches from the wrist to the ankle and acts like a controllable parachute or gliding surface.

Flying squirrels do not truly fly like bats or birds. They launch from branches, spread their limbs to tighten the patagium, and steer by changing the position of their legs, arms, and tail. A specialized cartilage projection at the wrist helps support the leading edge of the membrane. Their flattened tails provide stability and help them brake before landing.

The name refers to a whole group of squirrels, not one single species. Flying squirrels belong to the tribe Pteromyini, which includes roughly 50 species. Most are active at night, when darkness helps them avoid many daytime predators and compete less directly with other tree-dwelling animals.

Colugos and sugar gliders also glide using skin membranes, but they are not squirrels. Colugos are in their own mammalian order, while sugar gliders are marsupials. Flying squirrels are true rodents and are closely related to tree squirrels.