Bumblebee bats are sometimes called Kitti's hog-nosed bats. They live in Thailand. They are the tiniest bats and the smallest mammals in the world. They are about the size of a bumblebee and they weigh less than a dime. Bumblebee bats have a wingspan of five and a half inches. Their wingspan is smaller than some butterflies. They were only discovered in 1973. The bumblebee bat is one of the rarest bats in the world.