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
Do not feed the animals animals aggressively seeking out food from people, sometimes resulting in injury. Zoos generally discourage visitors from giving any food to the animals. Some zoos, particularly petting zoos, do the opposite and actively encourage people to get involved with the feeding of the animals. This, however, is strictly monitored and usually involves set food available from the zookeepers or vending machines, as well as a careful choice of which animals to feed, and the provision of hand-washing facilities to avoid spreading disease. Domestic animals such as sheep and goats are often permitted to be fed, as are giraffes. In national parks