Western mastiff bats live in rugged, rocky canyons typical of the arid Southwest, where they inhabit crevices in vertical cliffs. Because of their relatively large body size and narrow wings, these bats are unable to take off from a flat surface, and must instead freefall from a height to initiate flight. Hanging upside-down in a crevice, it can let go, gain airspeed as it drops, and flap away for its nightly hunt for insect prey. If an individual is on the ground, it will scramble up a tree or other object to get high enough to be able to launch itself into flight. In the early 1900s, they often roosted in buildings in southern California, but this may not be the case today.
Links:Mammal Species of the WorldClick here for The American Society of Mammalogists species account
Original description: Schinz, H.R., 1821. Das Thierreich eingetheilt nach dem Bau der Thiere als Grundlage ihrer Naturgeschichte und der vergleichenden Anatomie von dem Herrn Ritter von Cuvier. Stuttgart, Germany, 1:870.