Bat prevent them from spending too much time in unfamiliar places, and decrease predation. In some species, pregnant individuals may not use torpor. The smallest bat is Kitti's hog-nosed bat ("Craseonycteris thonglongyai"), which is long with a wingspan and weighs . It is also arguably the smallest extant species of mammal, next to the Etruscan shrew. The largest bats are a few species of "Pteropus" megabats and the giant golden-crowned flying fox, ("Acerodon jubatus"), which can weigh with a wingspan of . Larger bats tend to use lower frequencies and smaller bats higher for echolocation; high-frequency echolocation is better at detecting
Lesser long-eared bat sight is mostly restricted to aerial prey while they a technique that the species uses to take advantage of seasonal booms of tettigoniid crickets as well as general ground and aerial prey, known as passive listing. This method of hunting does not rely on sight or echolocation. Some moths species, like noctuids, have evolved to develop their own form of "ears" that are able to pick up the frequency of bat calls, however they are unable to sense long-eared bats as the bats use a minute whispering technique different from echolocation which bounces off the moths and is picked up