From the Flickr description:

I learned tonight that Petauroides volans is actually a gliding possum and is more closely related to the Lemur-like Ringtail Possum than other gliders. They are nocturnal marsupials, eating mostly eucalyptus leaves. About the size of a cat but considerably longer (about a metre long including the tail), they have a membrane stretching from each elbow to the knee. When extended this membrane forms a kind of wing that allows them to glide up to a reported 100m. We didn’t see any gliding this night.

I would have been a bit surprised to see it glide, it looks kind of chubby!

Via Julian Robinson’s Flickr photostream.