Bats are the only mammals that truly fly

Plenty of mammals can launch themselves through the air — flying squirrels and colugos stretch skin membranes to glide between trees — but only bats generate lift and stay aloft under their own power. They are the only mammals capable of true, flapping flight.

A bat’s wing is essentially a hand. The upper arm, forearm, and dramatically elongated finger bones support a thin membrane of skin, giving the wing the articulation of a human hand rather than the rigid feathered design of a bird. Tiny muscles embedded in the membrane let bats fine-tune its stiffness mid-flight.

That blueprint has been wildly successful. With over 1,400 species worldwide, bats make up roughly a fifth of all mammal species and live on every continent except Antarctica — pollinating plants, spreading seeds, and devouring vast quantities of insects.