Tadarida Brasiliensis Adjusts Echolocation Calls to Detect Cave Opening: Evidence for Bimodal Sensing in Bats

Kathryn McGowan Saint Mary's College
Faculty Sponsor(s): Laura Kloepper Saint Mary's College
While both bats and dolphins use sonar to get a picture of their environment, both have visual acuity and the ability to perceive objects through vision. The ability to ingrate information from vision and echolocation has been widely studied in dolphins and other cetaceans with studies suggesting that cetaceans use multimodal sensing to improve accuracy and target identification. While little is known about the extent to which bats integrate vision and echolocation, bats are known to exhibit behavioral changes when vision is obstructed compared to environments where ambient lights allows for use of visual cues. This suggests that like cetaceans, bats may integrate vision with echolocation when sensing their environment. In this study, we examined how Brazilian free-tailed bats (Tadarida Brasiliensis) use their echolocation calls in an open field compared to calls used during reentry to the roost. We extracted individual echolocation calls from two locations, an open field and the cave edge, during daylight and dark hours. Results demonstrated that calls exhibit decreased duration and increased bandwidth at the cave edge compared to the open field under both light conditions. Additionally, there was no significant difference in parameters of the calls recorded in the open field between hours of daylight and darkness, but all the call parameters were significantly different between daylight and darkness hours at the cave edge. The results of this study provide the first insight into bimodal sensing in bats and how bats adjust echolocation calls based on levels of ambient light.
Oral Presentation

When & Where

10:30 AM
Gallahue Hall 102