Sound propagation in the near and far-field of a broadband echolocating dolphin and a narrowband echolocating porpoise

Wei, Chong; Au, Whitlow W. L.; Ketten, Darlene R.; Vishnu, Hari; Ho, Abel Zhong Hao

doi:10.1121/2.0001036

Cited by 2 publications

(2 citation statements)

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“…Most dolphins of the infraorder Delphinida, particularly delphinids, produce broadband sounds (BB) for echolocation (Au, 2000). However, some lineages have independently evolved the ability to produce highly directional (Wei et al, 2019) narrow-band high frequency (NBHF) sounds (Kyhn et al, 2010) has revealed that species with highly directional signals convergently developed distinct head features to achieve increased directionality (Frainer et al, 2019a). However, feeding strategy might also determine sound emission patterns as not only preferred preys might differ between strategies (McCurry et al, 2017), but emitted sounds may also be affected by distinct rostrum morphologies adapted for suction or raptorial feeding (Song et al, 2016;Werth, 2006).…”

Section: Introductionmentioning

confidence: 99%

“…Most dolphins of the infraorder Delphinida, particularly delphinids, produce broad‐band sounds (BB) for echolocation (Au, 2000). However, some lineages have independently evolved the ability to produce highly directional (Wei et al, 2019) narrow‐band high frequency (NBHF) sounds (Kyhn et al, 2010) for echolocation as observed in Kogia species, Pontoporia blainvillei , Phocoenidae and Cephalorhynchus species. Investigation of the evolution of the sound generating structures in Delphinida has revealed that species with highly directional signals convergently developed distinct head features to achieve increased directionality (Frainer et al, 2019a).…”

Section: Introductionmentioning

confidence: 99%

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Head adaptation for sound production and feeding strategy in dolphins (Odontoceti: Delphinida)

et al. 2020

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Head morphology in toothed whales evolved under selective pressures on feeding strategy and sound production. The postnatal development of the skull (n = 207) and mandible (n = 219) of six Delphinida species which differ in feeding strategy but exhibit similar sound emission patterns, including two narrow-band high-frequency species, were investigated through 3D morphometrics. Morphological changes throughout ontogeny were demonstrated based on the main source of variation (i.e., prediction lines) and the common allometric component. Multivariate trajectory analysis with pairwise comparisons between all species was performed to evaluate specific differences on the postnatal development of skulls and mandibles. Changes in the rostrum formation contributed to the variation (skull: 49%; mandible: 90%) of the entire data set and might not only reflect the feeding strategy adopted by each lineage but also represents an adaptation for sound production and reception. As an important structure for directionality of sound emissions, this may increase directionality in raptorial feeders. Phylogenetic generalized least squares analyses indicated that shape of the anterior portion of the skull is strongly dependent on phylogeny and might not only reflect feeding mode, but also morphological adaptations for sound production, particularly in raptorial species. Thus, postnatal development seems to represent a crucial stage for biosonar maturation in some raptorial species such as Pontoporia blainvillei and Sousa plumbea. The ontogeny of their main tool for navigation and hunting might reflect their natural history peculiarities and thus potentially define their main vulnerabilities to anthropogenic changes in the environment.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Head adaptation for sound production and feeding strategy in dolphins (Odontoceti: Delphinida)

et al. 2020

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Modeling of the near to far acoustic fields of an echolocating bottlenose dolphin and harbor porpoise

Wei

Ketten

2020

The Journal of the Acoustical Society of America

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Echolocation signals emitted by odontocetes can be roughly classified into three broad categories: broadband echolocation signals, narrowband high-frequency echolocation signals, and frequency modulated clicks. Previous measurements of broadband echolocation signal propagation in the bottlenose dolphin (Tursiops truncatus) did not find any evidence of focusing as the signals travel from the near-field to far-field. Finite element analysis (FEA) of high-resolution computed tomography scan data was used to examine signal propagation of broadband echolocation signals of dolphins and narrowband echolocation signals of porpoises. The FEA results were used to simulate the propagation of clicks from phonic lips, traveling through the forehead, and finally transmission into the water. Biosonar beam formation in the near-field and far-field, including the amplitude contours for the two species, was determined. The finite element model result for the simulated amplitude contour in the horizontal plane was consistent with prior direct measurement results for Tursiops, validating the model. Furthermore, the simulated far-field transmission beam patterns in both the vertical and horizontal planes were also qualitatively consistent with results measured from live animals. This study indicates that there is no evidence of convergence for either Tursiops or Phocoena as the sound propagates from the near-field to the far-field.

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Sound propagation in the near and far-field of a broadband echolocating dolphin and a narrowband echolocating porpoise

Cited by 2 publications

References 26 publications

Head adaptation for sound production and feeding strategy in dolphins (Odontoceti: Delphinida)

Head adaptation for sound production and feeding strategy in dolphins (Odontoceti: Delphinida)

Modeling of the near to far acoustic fields of an echolocating bottlenose dolphin and harbor porpoise

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