The Nycteridae comprise a family of bats commonly called slit-faced or hollow-faced bats. They are grouped in a single genus, Nycteris. The bats are found in East Malaysia, Indonesia, and many parts of Africa. They are small bats, from 4 to 8 cm in body length, and with grey, brown, or reddish fur. A long slit runs down the centre of their faces from between the eyes to the nostrils, and probably assists in echolocation. They have large ears, and a complex nose-leaf. Their tails end in a T-shape, formed from cartilage, a unique feature among mammals. Their dental formula is: