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
Human echolocation details about their environment; however, others actively produce mouth clicks and are able to gauge information about their environment using the echoes from those clicks. Both passive and active echolocation help blind individuals learn about their environments. Because sighted individuals learn about their environments using vision, they often do not readily perceive echoes from nearby objects. This is due to an echo suppression phenomenon brought on by the precedence effect. However, with training, sighted individuals with normal hearing can learn to avoid obstacles using only sound, showing that echolocation is a general human ability. Vision and hearing are closely related