Megabat evolved early in the lineage of chiropterans. Although echolocation was later lost in family Pteropodidae, bats in the genus "Rousettus" are capable of primitive echolocation through clicking their tongues, and some species have been shown to create clicks similar to those of echolocating bats using their wings. Both echolocation and flight are energetically expensive processes. The nature of the flight and echolocation mechanism of bats allows for creation of echolocation pulses with minimal energy use. Energetic coupling of these two processes is thought to have allowed for both energetically expensive processes to evolve in bats. The loss of echolocation may
Robert Galambos generate and hear sounds an octave higher than can be heard by humans and other animals. Experiments they conducted used methods developed by Hallowell Davis to monitor the brains of bats and their hearing responses as they navigated their way past wires suspended from a laboratory ceiling. They showed how bats used echolocation to accurately avoid obstacles, which they were unable to do if their mouths or ears were kept shut. Griffin coined the term "echolocation" in 1944 to describe the phenomenon, which many physiologists of the day could not believe was possible. Using electrodes implanted in the brains of