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
Animal echolocation naturalist Louis Jurine repeated Spallanzani's experiments (using different species of bat), and concluded that when bats hunt at night, they rely on hearing. In 1908, Walter Louis Hahn confirmed Spallanzani's and Jurine's findings. In 1912, the inventor Hiram Maxim independently proposed that bats used sound below the human auditory range to avoid obstacles. In 1920, the English physiologist Hamilton Hartridge correctly proposed instead that bats used frequencies above the range of human hearing. Echolocation in odontocetes (toothed whales) was not properly described until two decades after Griffin and Galambos' work, by Schevill and McBride in 1956. However, in 1953, Jacques