When it comes to defining mammals, it can get confusing. What makes something an animal but not a mammal? Mammals give birth to live young, grow hair or fur in some way, are warm-blooded, nourish their young with milk secreted from mammary glands, and can’t fly. One of these facts is not actually true and is a common misconception about mammals. The fact is that whether an animal can or can’t fly has nothing to do with it being a mammal. Yet today only one mammal has the ability to fly, which can lead to some confusion.
The bat is the only mammal that can fly. The bird is the only dinosaur that can fly and the insect is the only arthropod that can fly. All of these exceptional animals are unique in their abilities because of how evolution forced them to develop. At some point, the evolution of flight was required to survive.
It would be a mistake, though, to think that very few mammals fly. There are an estimated 5000 mammal species in the world today and over 1200 of them can fly, they just all happen to be bats. That is the second-largest group of mammals of any group behind the rodent.
There are some other mammals who think they can fly. If you were able to ask the flying squirrel, the lemur and others if they were able to fly, they would surely say yes. While we would never say this to their face, the reality is that those animals glide, or fall with grace. While it is pretty impressive, they just don’t make the cut.
This makes the bat a pretty special mammal and one that we should pay closer attention to. It is strange to think that humans and bats all come from the same subcategory of animals and are yet so different.