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
Virginia big-eared bat make sounds that then echo off of objects around them, enabling them to find their prey while flying in the dark. Typically they prey on insects like moths, beetles, termites, mosquitoes and flies. Without echolocation, the bats would not be able to locate food. When analyzed, 97% of Virginia big-eared bat fecal pellets showed that the bat had consumed and digested Lepidoptera. Lepidoptera is a classification of insects that contains butterflies and moths. In Kentucky a similar study was done, examining the fecal pellets and stomach contents of the bats in and around the caves. The processed food showed that