Most giant fruit bats navigate by sight and smell, not sonar
Megabats—fruit bats and flying foxes of family Pteropodidae—are the giants of the bat world, yet nearly a third weigh under fifty grams. With few exceptions they lack echolocation, trusting keen eyes and noses to find figs and nectar while microbats click through the dark.
Pteropodidae alone fills superfamily Pteropodoidea within Yinpterochiroptera. As of 2018, 197 species were described—about a third of them Pteropus flying foxes—across six subfamilies. The largest individuals reach about 1.45 kilograms and 1.7-metre wingspans. Dog-like faces, a clawed second finger, and a reduced uropatagium set them apart; only a few species keep tails. Flight demands high metabolism: oxygen use soars, hearts can exceed seven hundred beats per minute, and lungs are large. George Dobson split bats into Mega- and Microchiroptera in 1875 by size and habits; genetics later nested megabats with some echolocating lineages in Yinpterochiroptera.
They likely arose in Australasia, with the living crown ancestor about thirty-one million years ago and a split from Rhinolophoidea near fifty-eight million years ago. Melanesia seeded many lineages that later reached Asia, the Mediterranean, and Africa in at least four colonization events. Fossils are the sparsest of any bat family—over ninety-eight percent of their fossil history may be missing—though isolated Late Eocene teeth from Thailand mark early records. Most species are nocturnal or crepuscular frugivores or nectar feeders; colonies can number a million, while others roost alone in trees or caves.
Slow maturity and usually a single pup after four to six months of pregnancy mean populations rebound slowly. A quarter of species are threatened by habitat loss and hunting for food; some are also watched as viral reservoirs. John Edward Gray named the family in 1821; Bonaparte corrected the spelling to Pteropodidae in 1838. Without laryngeal sonar, these Old World fruit bats still map the canopy—proof that bat success does not require an ultrasonic voice.
Source: Megabat
