The hammer-headed bat ('), also known as hammer-headed fruit bat and big-lipped bat, is a megabat widely distributed in West and Central Africa. It is the only member of the genus Hypsignathus, which is part of the tribe Epomophorini along with four other genera. It is the largest bat in continental Africa, with wingspans approaching 1 m, or about 3 ft, and males almost twice as heavy as females. Males and females also greatly differ in appearance, making it the most sexually dimorphic bat species in the world. These differences include several adaptations that help males produce and amplify vocalizations: the males' larynges (vocal cords) are about three times as large as those of females, and they have large resonating chambers on their faces. Females appear more like a typical megabat, with foxlike faces.