Megabat long, thus smaller than some microbats, for example, the Mauritian tomb bat. The largest attain a wingspan of , and weigh as much as . Most fruit bats have large eyes, allowing them to orient themselves visually in twilight and inside caves and forests. Their sense of smell is excellent. In contrast to the microbats, the fruit bats do not use echolocation (with one exception, the Egyptian fruit bat "Rousettus egyptiacus", which uses high-pitched tongue clicks to navigate in caves). Megabats make up the only family (Pteropodidae) in order Chiroptera that is not capable of laryngeal echolocation. Echolocation and flight
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