What mammals can fly?

Question

Which of these does not hold true for mammals?
[A] All Have a Backbone
[B] All have hair at some stage
[C] All Females have mammary gland
[D] All females give birth to live young

Answer 1

Bats are the only mammals that are able to fly.

The "flying squirrel" can only do what the gliding opposum does -- glide for short distances.