Sound Research WIKINDX |
Resource type: Journal Article Language: en: English Peer reviewed DOI: 10.1139/z98-043 BibTeX citation key: Fenton1998 Email resource to friend View all bibliographic details |
Categories: General Keywords: Bats, Ultrasound Creators: Fenton, Portfors, Rautenbach, Waterman Collection: Canadian Journal of Zoology |
Views: 8/352
|
Abstract |
Hunting aerial-feeding bats, species that take airborne prey (usually flying insects), use echolocation to detect, track, and assess targets. The echolocation calls of aerial-feeding bats at sites in Canada (British Columbia and Ontario), Mexico, Brazil, and Zimbabwe were significantly dominated by frequencies between 20 and 60 kHz, although at the more tropicallocations some aerial-feeding bats used echolocation calls with most energy <20 or >60 kHz. The impact of frequency-specificattenuation, perhaps combined with frequency-specific, hearing-based defenses of some insects, suggests that by using echolocation calls <20 kHz, bats could both extend the effective range of echolocation and make their calls less conspicuous to insect ears. Bats using calls >60 kHz would be less conspicuous to the insects. We found two patterns of echolocation-callbehaviour. Most adjacent echolocation calls, and all that were dominated by sounds >20 kHz, showed large (80%) overlap in bandwidth. The other pattern involved much less overlap in bandwidth (0–30%) between adjacent calls and was evident in the calls of the molossid Tadarida midas, which used echolocation calls dominated by sounds <20 kHz. This behaviour would allow the echolocating bat to extend its effective range of perception by separating in frequency the echoes returning from adjacent calls.
|