Insect-eating bats inhabiting regions with a temperate climate must in winter, when food-supplies cease, either hibernate or migrate to warmer regions. The majority hibernate; but two species at least of Canadian bats perform extensive migrations, it is supposed to escape the intense cold.
The power of flight has made the bats independent of the barriers which restrict the movements of terrestrial animals, and accordingly we find them all over the world, even as far north as the Arctic Circle. But certain groups of bats have an extremely restricted range. Thus the Fruit-bats occur only in the warmer regions of the Old World, the Vampires in America, whilst some of the more common insect-eating forms are found everywhere. Those forms with a restricted distribution are, it should be noticed, all highly specialised--that is to say, they have all become in some way adapted to peculiar local conditions, and cannot subsist apart therefrom. It is the more lowly--less specialised--forms which have the widest geographical range. There are some spots, however, on the world's surface from which no bat has yet been recorded--such are Iceland, St. Helena, Kerguelen, and the Galapagos Islands.
[Illustration: _Photo by Henry King_] [_Sydney._
In their roosting-places these bats hang all over the trees in enormous numbers, looking like great black fruits. Although shot in thousands, on account of the damage they do to fruit orchards, their numbers do not appear to be reduced.]
[Illustration: _Photo by A. S. Rudland & Sons._
The tubular nostrils distinguish this and a species of insect-eating bat from all other living mammals.]
These represent the giants of the bat world, the largest of them, the KALONG, or MALAY FOX-BAT, measuring no less than 5 feet from tip to tip of the wing. The best known of the fruit-bats is the INDIAN FOX-BAT. Sir J. E. Tennent tells us that a favourite resort of theirs near Kandy, in Ceylon, was some indiarubber-trees, "where they used to assemble in such prodigious numbers that large boughs would not infrequently give way beneath the accumulated weight of the flock." An observer in Calcutta relates that they occasionally travel in vast hordes, so great as to darken the sky. Whether they are performing some preconcerted migration or bent only on a foray to some distant feeding-ground is a matter for speculation. These hordes are quite distinct from the "long strings" which may be seen every evening in Calcutta on their way to neighbouring fruit-trees.