title: Bottlenose dolphin (Tursiops truncatus) detection of simulated echoes from normal and time-reversed clicks.
abstract: In matched filter processing, a stored template of the emitted sonar pulse is compared to echoes to locate individual replicas of the emitted pulse embedded in the echo stream. A number of experiments with bats have suggested that bats utilize matched filter processing for target ranging, but not for target detection. For dolphins, the few available data suggest that dolphins do not utilize matched filter processing. In this study, the effect of time-reversing a dolphin's emitted click was investigated. If the dolphin relied upon matched filter processing, time-reversal of the click would be expected to reduce the correlation between the (unaltered) click and the echoes and therefore lower detection performance. Two bottlenose dolphins were trained to perform a phantom echo detection task. On a small percentage of trials ("probe trials"), a dolphin's emitted click was time-reversed before interacting with the phantom echo system. Data from the normal and time-reversed trials were then analyzed and compared. There were no significant differences in detection performance or click emissions between the normal and time-reversed conditions for either subject, suggesting that the dolphins did not utilize matched filter processing for this echo detection task.
authors: U.S. Navy Marine Mammal Program, Space and Naval Warfare Systems Center Pacific, Code 71510, 53560 Hull Street, San Diego, California 92152.
authors: James J
authors: JJ
authors: Finneran
authors: National Marine Mammal Foundation, 2240 Shelter Island Drive, #200, San Diego, California 92106.
authors: Teri
authors: T
authors: Wu
authors: National Marine Mammal Foundation, 2240 Shelter Island Drive, #200, San Diego, California 92106.
authors: Nancy
authors: N
authors: Borror
authors: National Marine Mammal Foundation, 2240 Shelter Island Drive, #200, San Diego, California 92106.
authors: Megan
authors: M
authors: Tormey
authors: G2 Software Systems, 4250 Pacific Highway, Suite 125, San Diego, California 92110.
authors: Arial
authors: A
authors: Brewer
authors: G2 Software Systems, 4250 Pacific Highway, Suite 125, San Diego, California 92110.
authors: Amy
authors: A
authors: Black
authors: G2 Software Systems, 4250 Pacific Highway, Suite 125, San Diego, California 92110.
authors: Kimberly
authors: K
authors: Bakhtiari
mesh_terms: D000162:Acoustics; D000818:Animals; D001307:Auditory Perception; D050681:Bottle-Nosed Dolphin / Q000502:physiology* / Q000523:psychology*; D003198:Computer Simulation; D004455:Echolocation; D005260:Female; D008297:Male; D046709:Pattern Recognition, Physiological; D011571:Psychoacoustics; D012815:Signal Processing, Computer-Assisted; D013018:Sound Spectrography; D013997:Time Factors; D014828:Vocalization, Animal