Onychonycteris known species, hence "Onychonycteris" meaning "clawed bat". The specific epithet is a tribute to the fossil prospector and preparator who discovered it, Bonnie Finney. "Onychonycteris finneyi" was the strongest evidence so far in the debate on whether bats developed echolocation before or after they evolved the ability to fly. "O. finneyi" had well-developed wings, and could clearly fly, but lacked the enlarged cochlea of all extant echolocating bats, closer resembling the old world fruit bats which do not echolocate. This indicates that early bats could fly before they could echolocate. However, an independent evaluation of the "Onychonycteris" reference fossil in
Bulldog bat are long and narrow and their ears are large and funnel shaped. Unusual among bats, they have cheek-pouches for storing food. They also have full lips divided by a fold of skin giving a 'hare lip' look which together with the cheek pouches gives them their bulldog-like appearance. The species of lesser bulldog bats are insectivorous and whilst the greater bulldog bats also eat insects their chief food is fish. They use their echolocation to pinpoint the ripples they make on the surfaces of water. The greater bulldog bat trawls the water with its long, curved talons approximately 2–3 cm