A number of
animals have
evolved aerial locomotion, either by powered
flight or by
gliding.
Flying and gliding animals have evolved separately many times, without any single ancestor.
Flight has evolved at least four times, in the
insects,
pterosaurs,
birds, and
bats. Gliding has evolved on many more occasions. Usually the development is to aid
canopy animals in getting from tree to tree, although there are other possibilities. Gliding, in particular, has evolved among
rainforest animals, especially in the rainforests in
Asia (most especially
Borneo) where the
trees are tall and widely spaced. Several species of
aquatic animals, and a few
amphibians have also evolved to acquire this gliding flight ability, typically as a means of evading predators.