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
Generally recognized as safe and effective Generally recognized as safe and effective Generally recognized as safe and effective (abbreviated as GRASE, GRAS/E, or GRAS/GRAE) is designation for certain old drugs that do not require prior approval from the U.S. Food and Drug Administration in order to enter the United States marketplace because they are generally recognized as safe and effective by medical professionals. The Federal Food, Drug, and Cosmetic Act defines a "new drug", which requires prior approval, as any drug "the composition of which is such that such drug is not generally recognized, among experts qualified by scientific training and experience to evaluate the safety