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
Crawford's gray shrew Instead, it builds small nests in pack rat houses or under dead agaves. This species also conserves water by being nocturnal, unlike other shrews, which hunt day and night to avoid starvation. Crawford's gray shrew has poor vision, so it uses its highly sensitive ears and long nose to hunt down its prey. It will also use an echolocation, similar to bats, with high-pitched squeaks to locate prey. It will also store food during the night so it will not have to go out during the day. To keep from losing any water from its victims, it will bite off