Bats are not rodents with wings, contrary to popular belief. like all rodents, bats are mammals, but they have a skeleton similar to the human skeleton. The bones in bat wings are much like those in arms and the human hand, with a thumb and four fingers. In bats, the bones of the arms and the four fingers of the hands are very long. The bone structure helps support the web of skin that stretches from the body to the ends of the fingers to form wings.