Bats

Mammals in the Chiroptera order include Bats. They are the only animals that can truly and continuously fly thanks to the adaptation of their forelimbs as wings. When flying, bats are more nimble than most birds because they use their extremely long, spread-out digits, which are protected by a thin membrane called a patagium.

In the winter, bats hibernate. Big brown bats can hibernate for 64–66 days in the wild, but one lasted an amazing 344 days in captivity! These little fellas don't need to eat, but they do need to drink when they wake up. Some bats only breathe every two hours, and their heart rates plummet from 1000 to merely 25 beats per minute. Because it takes less energy to utilize stored fat for survival than to travel in search of food, a bat's body temperature drops, and its metabolic rate slows. For the duration of their hibernation, bats need roosts that are cold and keep a constant temperature.