When the bat alights on the ground, as it but seldom does, it shows itself a genuine quadruped. It draws its fingers together, throwing the membrane of the wing into folds, and so the free, strongly clawed thumb projects, and on this claw, and the hind feet which are free to the ankles, the bat walks, but as you might expect, its gait is very awkward. The bat is a night-flying creature. Its sight is better suited for night than daylight; it prefers twilight, or dark caverns. Like the owl and the moth it sleeps by day, and comes out after sunset. As it eats insects it frequents shady places where insects can be found; during the day it rests in cool, dark places where there is some rough surface to which it can cling. Thus, dark woods, hollow trees, old barns, abandoned houses, church towers, and caves are the choice haunts of the bat. From its habit of hiding, its night-flying, its uncouth motion, its mouse-like body and unfeathered wings, which are so unhandsome that artists have copied them when they wish to show demons, witches, dragons, harpies, and evil angels with wings, the poor bat has derived its unlucky reputation, and the general dislike with which it is regarded. In truth, there is scarcely any creature so frail, defenceless, harmless, friendly, gentle, and timid as a bat. It has no weapons, and its only hope of defence lies in its quick, erratic flight.[86] During the day in its dark shelter, the bat sleeps in a strange fashion. It hangs itself up on some projecting stone or twig, as you would hang a cloak on a peg, or an umbrella by the crook on the handle. It hangs head down, using the large hooked claws on the hind-feet to cling by, and queer as the position is, it seems to suit very well. Bats are social in nature, and live in large flocks or bands. A cave or tower may have its walls quite covered with them, hanging close together. Sometimes, especially in winter, they cling one to the other in a curious, compact mass. Bats hibernate, or sleep, through cold weather, hiding themselves in tree-caves or other dark places early in the autumn, and coming forth when the spring is fully opened and has brought their insect food. When the bat goes abroad it spends all its time in hunting for insects. Our common bat is a most useful creature, destroying thousands of insects which would be harmful to our garden and fruit trees. In a season, a bat eats myriads of gnats, midges, moths, beetles, cockroaches, crickets, and grasshoppers.