A bat's breathing rate, heartbeat, and body temperature, unlike those of many other mammals, vary greatly, depending on its activities and the temperature of its surroundings. Among some species, the temperature of a resting bat becomes the same as that of its environment. The face and head of bats vary greatly among the various species. Some bats have a head shaped like that of a miniature bear or dog. Other bats have a flatter face.
Some species have folds of skin called a nose-leaf on their snout.
The nose-leaf may look like a spearhead or a blade. Bats have a good sense of smell that helps them find food and their roost. Most bats have small, sharp teeth that reduce food to a soupy texture. Bats digest their food more quickly than many other mammals. This rapid digestion helps them avoid having extra weight while flying.