Depth dependent variation of the echolocation pulse rate of bottlenose dolphins (<i>Tursiops truncatus</i>)

Simard, Peter; Hibbard, Ashley L.; McCallister, Kimberly A.; Frankel, Adam S.; Zeddies, David G.; Sisson, Geoffrey M.; Gowans, Shannon; Forys, Elizabeth A.; Mann, David A.

doi:10.1121/1.3257202

Cited by 20 publications

(25 citation statements)

References 39 publications

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“…In comparison, the typical mean ICIs of bottlenose dolphins in the wild may be two to four times longer (Wahlberg et al, 2011). Assuming a lag time of 20 ms (Morozov et al, 1972;Au, 1993), the mean ICIs found for botos correspond to an upper search distance averaging just 11 m (sound speed: 1500 m s −1 ), whereas the mean ICI of 63-120 ms measured for two species of bottlenose dolphin (Wahlberg et al, 2011) corresponds to upper search distances from 32-75 m, conforming with other studies investigating active biosonar ranges (Au et al, 2007;Simard et al, 2010). We therefore conclude that botos operate a shortrange biosonar system, which may be reflected in their behaviour by their relatively slow swim speeds of usually less than 1 m s −1 (Best and da Silva, 1989).…”

Section: Fast Biosonar Sampling Ratessupporting

confidence: 50%

Amazon river dolphins (Inia geoffrensis) use a high-frequency short-range biosonar

Ladegaard

Jensen

Freitas

et al. 2015

Journal of Experimental Biology

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Toothed whales produce echolocation clicks with source parameters related to body size; however, it may be equally important to consider the influence of habitat, as suggested by studies on echolocating bats. A few toothed whale species have fully adapted to river systems, where sonar operation is likely to result in higher clutter and reverberation levels than those experienced by most toothed whales at sea because of the shallow water and dense vegetation. To test the hypothesis that habitat shapes the evolution of toothed whale biosonar parameters by promoting simpler auditory scenes to interpret in acoustically complex habitats, echolocation clicks of wild Amazon river dolphins were recorded using a vertical seven-hydrophone array. We identified 404 on-axis biosonar clicks having a mean SL pp of 190.3±6.1 dB re. 1 µPa, mean SL EFD of 132.1±6.0 dB re. 1 µPa 2 s, mean F c of 101.2±10.5 kHz, mean BW RMS of 29.3±4.3 kHz and mean ICI of 35.1±17.9 ms. Piston fit modelling resulted in an estimated half-power beamwidth of 10.2 deg (95% CI: 9.6-10.5 deg) and directivity index of 25.2 dB (95% CI: 24.9-25.7 dB). These results support the hypothesis that river-dwelling toothed whales operate their biosonars at lower amplitude and higher sampling rates than similar-sized marine species without sacrificing high directivity, in order to provide high update rates in acoustically complex habitats and simplify auditory scenes through reduced clutter and reverberation levels. We conclude that habitat, along with body size, is an important evolutionary driver of source parameters in toothed whale biosonars.

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Section: Fast Biosonar Sampling Ratessupporting

confidence: 50%

Amazon river dolphins (Inia geoffrensis) use a high-frequency short-range biosonar

Ladegaard

Jensen

Freitas

et al. 2015

Journal of Experimental Biology

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“…The spectra of extreme off-axis clicks were also published [315]. While click rates are listed in many publications, these can depend on the depth of the animal during a foraging dive [316].…”

Section: Tursiops Truncatus-bottlenose Dolphinmentioning

confidence: 99%

Review of Underwater and In-Air Sounds Emitted by Australian and Antarctic Marine Mammals

et al. 2017

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The study of marine soundscapes is a growing field of research. Recording hardware is becoming more accessible; there are a number of off-the-shelf autonomous recorders that can be deployed for months at a time; software analysis tools exist as shareware; raw or preprocessed recordings are freely and publicly available. However, what is missing are catalogues of commonly recorded sounds. Sounds related to geophysical events (e.g. earthquakes) and weather (e.g. wind and precipitation), to human activities (e.g. ships) and to marine animals (e.g. crustaceans, fish and marine mammals) commonly occur. Marine mammals are distributed throughout Australia's oceans and significantly contribute to the underwater soundscape. However, due to a lack of concurrent visual and passive acoustic observations, it is often not known which species produces which sounds. To aid in the analysis of Australian and Antarctic marine soundscape recordings, a literature review of the sounds made by marine mammals was undertaken. Frequency, duration and source level measurements are summarised and tabulated. In addition to the literature review, new marine mammal data are presented and include recordings from Australia of Omura's whales (Balaenoptera omurai), dwarf sperm whales (Kogia sima), common dolphins (Delphinus delphis), short-finned pilot whales (Globicephala macrorhynchus), long-finned pilot whales (G. melas), Fraser's dolphins (Lagenodelphis hosei), false killer whales (Pseudorca crassidens), striped dolphins (Stenella coeruleoalba) and spinner dolphins (S. longirostris), as well as the whistles and burst-pulse sounds of Australian pygmy killer whales (Feresa attenuata). To date, this is the most comprehensive acoustic summary for marine mammal species in Australian waters.

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“…Some aspects of the acoustic behavior of echolocating free-ranging bottlenose dolphins have been described already by Norris (1967Norris ( , 1969. More recent and detailed information has been provided by Jensen et al (2009b) for T. aduncus and Simard et al (2009) for T. truncatus. However, some of the basic source parameters of the clicks from freeranging bottlenose dolphins are still unknown, despite the bottlenose dolphin being the most studied of all cetacean species.…”

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confidence: 99%

Source parameters of echolocation clicks from wild bottlenose dolphins (Tursiops aduncusandTursiops truncatus)

Wahlberg

Jensen

Soto

et al. 2011

The Journal of the Acoustical Society of America

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The Indian Ocean and Atlantic bottlenose dolphins (Tursiops aduncus and Tursiops truncatus) are among the best studied echolocating toothed whales. However, almost all echolocation studies on bottlenose dolphins have been made with captive animals, and the echolocation signals of freeranging animals have not been quantified. Here, biosonar source parameters from wild T. aduncus and T. truncatus were measured with linear three-and four-hydrophone arrays in four geographic locations. The two species had similar source parameters, with source levels of 177-228 dB re 1 lPa peak to peak, click durations of 8-72 ls, centroid frequencies of 33-109 kHz and rms bandwidths between 23 and 54 kHz. T. aduncus clicks had a higher frequency emphasis than T. truncatus. The transmission directionality index was up to 3 dB higher for T. aduncus (29 dB) as compared to T. truncatus (26 dB). The high directionality of T. aduncus does not appear to be only a physical consequence of a higher frequency emphasis in clicks, but may also be caused by differences in the internal properties of the sound production system.

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Depth dependent variation of the echolocation pulse rate of bottlenose dolphins (Tursiops truncatus)

Cited by 20 publications

References 39 publications

Amazon river dolphins (Inia geoffrensis) use a high-frequency short-range biosonar

Amazon river dolphins (Inia geoffrensis) use a high-frequency short-range biosonar

Review of Underwater and In-Air Sounds Emitted by Australian and Antarctic Marine Mammals

Source parameters of echolocation clicks from wild bottlenose dolphins (Tursiops aduncusandTursiops truncatus)

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