Bioacoustics of Trachops cirrhosus

Activity patterns. Fringe-lipped Bats become active less than 30 minutes after sunset. They leave their roosts and conduct relatively short flights (average 220 m from roost) and then perch in a sit-and-wait strategy listening for acoustic cues emitted by prey. After they detect prey, an attack is launched with a brief flight from the perch. They fly in short bouts, with longest flights averaging c.12 minutes. When all flights were accumulated over the entire night,six bats flew an average of 68 minutes in one night, indicating that only c.11% of their time budget was spent in flight; remainder of time was spent perching, supposedly eavesdropping for calling prey. They roost in caves, culverts, archaeological remains, hollow trees, mines, and abandoned buildings.

Food and Feeding. Fringe-lipped Bats are considered foliage-gleaning carnivores, with very diverse diets. They eat beetles, orthopterans, several species of frogs, lizards such as geckos and anoles, bats, and even prey as large as mouse opossums weighing onethird of their body weight. They sometimes eat fruit. They eavesdrop on unsuspecting, calling prey such as tungara frogs (Engystomops pustulosus) or katydids. They conduct shortflights to their hunting grounds, but if hunting frogs, they can fly longer. They are also sit-and-wait predators, seeking acoustic cues from their prey while perched in a tree or other surface, from which the attack is then launched. Fringe-lipped Bats are rapid learners that can incorporate cues and information from the environment into their foraging habits—e.g. they can learn that a sound represents new prey and identify new prey by listening to other species of gleaning bats.