“ In habits bats are social, nocturnal and crepuscular; the insect-eating species feed on the wing, in winter in the temperate regions they migrate to a warmer climate, or hibernate, as do the British bats. The sense-organs are highly developed; the wing-membranes are exceedingly sensitive; the nose-leaf is also an organ of perception, and the external ear is specially modified to receive sound-waves. Most bats are insect-eaters, but the tropical “flying foxes” or fox-bats of the Old World live on fruit; some are blood-suckers, and two feed on small fish. ”