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
Mauritian tomb bat consumes it while in flight. Their preferred food is moths, though during daylight hours they will prey upon butterflies and termites. In regions where the bats live, they often are a factor in keeping pest populations down. This is important since the bats inhabit areas often plagued by insect-borne diseases such as malaria. They usually wait for complete darkness before foraging. Over open areas, they can detect their prey at long ranges. They periodically make dives when hunting, and with each dive, they increase the rate of echolocation. The bats use audible calls to communicate with each other. When at