Egyptian fruit bat their days roosting in trees or caves, often with large groups of other bats, sometimes numbering in the thousands. They emerge from the roost to forage for food in the late evening, and return just before dawn. They hang upside down, with their wings folded closely around their bodies. Egyptian fruit bats, along with other species in the genus "Rousettus", are the only megachiropterid bats to use echolocation, which they accomplish by emitting a series of sharp clicks with their tongues. The clicks are normally slow and constant, but these clicks speed up dramatically when the bats approach an object.
Lazzaro Spallanzani with frogs, and an artificial insemination, using a dog. Spallanzani showed that some animals, especially newts, can regenerate some parts of their body if injured or surgically removed. Spallanzani is also credited with the classification of tardigrades, which are one of the most durable extremophiles still to this day. (See Binomial Nomenclature) Spallanzani is also famous for extensive experiments on the navigation in complete darkness by bats, where he concluded that bats do not use their eyes for navigation in total darkness, but some other sense (see animal echolocation). He was the pioneer of the original study of echolocation, though