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
Cycnia tenera range, but is most commonly reported from dogbane. Its interactions with bats have been much studied, but are an area of dispute regarding whether the clicks emitted by adult moths are disruptive of bat echolocation, or merely aposematic warning signals. The two functions are not mutually exclusive, however, so it may not be possible to resolve the issue. The moth's coloration appears to be aposematic for insectivorous birds. Chemical signals do not prevent bats from attacking, but do cause bats to release "C. tenera" they have caught. This moth has several generations per year through much of its range, so