MadSci Network: Zoology |
There are actually a lot of vertebrates that can fly. Most of them are birds, but one group of mammals can fly, too: the bats. Birds and bats have evolved very light, partially hollow bones to help them fly. So where do flying squirrels fit in? Well, they don't really fly. They can glide from a tree to another tree, and they may even be able to glide upwards for short distances, but they can't fly under their own power, as bats and birds can. They have a length of skin stretching from their arms to their legs, and when they leap from a tree, they spread out all their limbs so this skin is stretched as far as it can be. This makes a wide area for air to push up on, and because their bodies are pretty light (though not as light as a bat's or a bird's), they can glide along on air currents for a while.