Bioacoustics of Cardioderma cor

Movements, Home range and Social organization. Heartnosed False-vampires roost in colonies of a few to more than 100 individuals. Colonies may change over time. Each night, bats fly from their roosts to foraging territories of 0-1-1 ha that may be 0-4-1-2 km from the roost tree. They defend their territories with loud songs that are quite distinct from their echolocation calls. The song is emitted through the mouth and consists of a series of 4-9 pulses within one second, repeated several times per minute, sometimes throughout much of the night. Frequencies of each pulse are 6-20 kHz, with peak energy at c.12 kHz, and songs can be heard by humans up to 100-200 m away. Males appear to sing most often, and songs vary seasonally. Females share a male’s territory, at least during some times of year, and might return to the same territory in subsequent years suggesting a long-term pair bond. Both members of the pair perch next to each other while foraging. Heartnosed False-vampires also have a low-frequency call given occasionally during flight that might have a social function. They usually do not share roosts with other species.

Activity patterns. Heart-nosed False-vampires rest during the day but can remain alert in the roost, presumably looking for predators. They hunt for food at night and start becoming active at sunset but do not emerge from their roosts until ¢.30 minutes later. They are not known to use torpor or hibernate. Selection of day roosts varies geographically, depending on availability. In dry savanna, most commonly reported roost is in hollow trees, especially baobab ( Adansonia , Malvaceae ), but they have also been found in unused huts or houses and inside an outhouse. In other areas, they regularly use caves. In Ethiopia , they have also been reported in ash flow tuft blisters (cavities in volcanic rock). Echolocation pulses used for navigation are very short (1-3 milliseconds) FM calls, with average interpulse interval of 48 milliseconds. Most energy is in the second and third harmonics, with peak energy in second harmonic at c.49 kHz, which has typical bandwidth of ¢.22 kHz sweeping from 62 kHz to 40 kHz. First harmonic (fundamental) is usually much softer and still above human hearing (30-20 kHz). Predation by a snake has been reported, and it is likely that various mammals might also attempt to catch bats at roosts.