Tuesday, March 07, 2017

Fulbright National Geographic Stories: Borneo’s Gliding Giants

Just as the sun sets a whiskered nose pokes out of a hole 15 stories above the forest floor. As the light dims a furry head, body, and massive tail follow.

Crawling on a branch it isn’t unstable, just a bit awkward and perhaps overburdened, like when you have to delicately shuffle your way over to the coffee maker in the morning because your whole comforter is still cloaked around you.

After carefully scanning the surroundings, this arboreal acrobat crouches down, takes aim, and launches itself into the warm night air.

This is how the flying squirrel begins its night, and not just any flying squirrel – this is the giant flying squirrel.

There are more flying squirrels found in Borneo than anywhere else on earth. Out of the 49 species of flying squirrels throughout the world, 14 are found in Borneo, including four giant flying squirrel species.

You can see below two different species of giant flying squirrels using the same tree at the Rainforest Discovery Center near the Sepilok Forest Reserve in Sabah, Malaysia.

On the left is a Red Giant Flying Squirrel (Petaurista petaurista), easily identified by the dark tip on its tail.

The on the right is the Black Giant Flying Squirrel (Aeromys tephromelas).

There are two other giant flying squirrel species found in Borneo, the Spotted Giant Flying Squirrel (Petaurista elegans) and the Thomas’s Giant Flying Squirrel (Aeromys thomasi).

Flying squirrels don’t actually fly; they glide using a membrane of skin that connects their front and back limbs called patagium.

The name is derived from the Greek word “patageion,” which referred to the gold lining at the edge of a woman’s tunic.

By stretching out this membrane as they leap from some of the tallest trees in the tropics, giant flying squirrels can travel well over 150 meters.

The trajectories of flying squirrels in the air were once thought to be something of a gamble, but research on Northern Flying Squirrels in North America has shown that they are actually quite agile in their gliding.

They are able to steer themselves in the air and even weave around trees by tensing muscles on either side of their patagium.