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- Blomqvist, Christer, 1963-, et al.
(författare)
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An acoustic tag for recording, directional, pulsed ultrasounds aimed at free-swimming Bottlenose dolphins (Tursiops truncatus) by conspecifics
- 2004
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Ingår i: Aquatic Mammals. - 0167-5427 .- 1996-7292. ; 30:3, s. 345-356
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Tidskriftsartikel (refereegranskat)abstract
- We developed an acoustic tag, called MOSART (MObile Submersible Acoustic Recorder of Transients), for recording directional social pulses produced by a bottlenose dolphin (Tursiops truncatus). The tag was attached to the dorsal fin of two dolphins by means of suction cups. Two adult bottlenose dolphins at the Kolmårdens Djurpark, Sweden, were trained to carry the tag comfortably through a desensitising program. The tag included two envelope click-detectors, each with a narrow bandpass filter, centred at 120 and 70 kHz, respectively. The duration of the original pulses and their relative amplitude within the two filter frequency bands was retained. The amplitude differences between the two filter bands reflected changes in the source frequency spectrum and/or the position of the tag hydrophone in the incoming sound beam. The tag recorded "echolocation click trains," "slow and irregular pulses," and "pulse bursts" with varying amounts of energy in both frequency bands. The peak amplitude and duration of clicks in "echolocation click trains" and in "slow and irregular pulses" were logged correctly; however, the tag recorder had more difficulties in handling the complex pulses in the aggressive "pulse bursts," where the duration of the individual pulses could not be determined. Still, the amplitude and the pulse repetition rate could be measured. The possible impact of the tag was investigated by analysing the dolphin's behaviours (12 categories), sounds (3 categories), preferred location in the pool, and respiration intervals. Only four of the behaviours and one preferred location in the pool showed significant differences among pre-tag baselines, tag periods, and post-tag follow-ups, suggesting that the tag had only a minor impact on the dolphin. We describe and discuss the tag and its capacity to record different pulsed sounds.
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| 2. |
- Blomqvist, Christer, 1963-, et al.
(författare)
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High-frequency burst-pulse sounds in agonistic/aggresive interactions in bottlenose dolphins, Tursiops truncatus
- 2004
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Ingår i: Echolocation in bats and dolphins. - Chicago : The University of Chicago Press. - 0226795993 - 0226684466 - 9780226795997 ; , s. 425-431
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- Although bats and dolphins live in very different environments, are vastly different in size, and hunt different kinds of prey, both groups have evolved similar sonar systems, known as echolocation, to locate food and navigate the skies and seas. While much research has been conducted over the past 30 years on echolocation in bats and dolphins, this volume is the first to compare what is known about echolocation in each group, to point out what information is missing and to identity future areas of research. "Echolocation in Bats and Dolphins" consists of six sections: mechanisms of echolocation signal production; the anatomy and physiology of signal reception and interpretation; performance and cognition; ecological and evolutionary aspects of echolocation mammals; theoretical and methodological topics; and possible echolocation capability in other mammals, including shrews, seals and baleen whales. Animal behaviourists, ecologists, physiologists and both scientists and engineers who work in the field of bioacoustics should benefit from this book.The objectives of this study were to investigate whether burst-pulse sounds emitted in aggressive interactions contain ultrasonic frequencies similar to the sonar sounds and to describe their repetition rate patterns and concurrent visual behavior patterns.
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