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.
Large slit-faced bat fly over long distances. Although smaller bats are consumed by "N. grandis", they are only eaten when they fly into the roosts of "N. grandis". "N. grandis" produces low-intensity echolocation calls at high frequencies, which makes them nearly inaudible except at close range. Instead of relying on echolocation to find their prey, these bats listen for wing fluttering of smaller bats and even insects. However, as "N. grandis" gets closer to its prey during a hunt, it exudes a louder echolocation call. At the beginning of the pursuit, the call ranges from 17-114 kHZ, and rises to a range of