A long time ago, people used to think bats were birds without feathers. But now we know that there is no such thing as a featherless bird. We know that bats are MAMMALS, just like people.
Some of the things that tell us bats are mammals:
They give birth to live young who suckle milk, produced by the mother’s mammary glands.
But bats are very special mammals. They are the only mammals that can fly. Bats flap their wings and fly like a bird.