Hydrodynamic discrimination of wakes caused by objects of different size or shape in a harbour seal (Phoca vitulina)
Harbour seals can use their mystacial vibrissae to detect and track hydrodynamic wakes. We investigated the ability of a harbour seal to discriminate objects of different size or shape by their hydrodynamic signature and used particle image velocimetry to identify the hydrodynamic parameters that a...
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2011
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Online Access: | https://portal.findresearcher.sdu.dk/da/publications/a1b2b72c-acee-493a-91a3-dd0775f3e7fe https://doi.org/10.1242/jeb.053926 |
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ftsydanskunivpub:oai:sdu.dk:publications/a1b2b72c-acee-493a-91a3-dd0775f3e7fe 2024-05-12T08:04:52+00:00 Hydrodynamic discrimination of wakes caused by objects of different size or shape in a harbour seal (Phoca vitulina) Wieskotten, S. Mauck, B. Miersch, L. Dehnhardt, G. Hanke, W. 2011 https://portal.findresearcher.sdu.dk/da/publications/a1b2b72c-acee-493a-91a3-dd0775f3e7fe https://doi.org/10.1242/jeb.053926 eng eng https://portal.findresearcher.sdu.dk/da/publications/a1b2b72c-acee-493a-91a3-dd0775f3e7fe info:eu-repo/semantics/restrictedAccess Wieskotten , S , Mauck , B , Miersch , L , Dehnhardt , G & Hanke , W 2011 , ' Hydrodynamic discrimination of wakes caused by objects of different size or shape in a harbour seal (Phoca vitulina) ' , Journal of Experimental Biology , vol. 214 , no. 11 , pp. 1922-1930 . https://doi.org/10.1242/jeb.053926 article 2011 ftsydanskunivpub https://doi.org/10.1242/jeb.053926 2024-04-17T14:56:18Z Harbour seals can use their mystacial vibrissae to detect and track hydrodynamic wakes. We investigated the ability of a harbour seal to discriminate objects of different size or shape by their hydrodynamic signature and used particle image velocimetry to identify the hydrodynamic parameters that a seal may be using to do so. Hydrodynamic trails were generated by different sized or shaped paddles that were moved in the calm water of an experimental box to produce a characteristic signal. In a two-alternative forced-choice procedure the blindfolded subject was able to discriminate size differences of down to 3.6. cm (Weber fraction 0.6) when paddles were moved at the same speed. Furthermore the subject distinguished hydrodynamic signals generated by flat, cylindrical, triangular or undulated paddles of the same width. Particle image velocimetry measurements demonstrated that the seal could have used the highest velocities and the steepness of the gradients within the wake to discriminate object size, beside the size of counter-rotating vortices and the spatial extension of a wake. For shape discrimination the subject could have used the spatial extension of the whole wake, in addition to the arrangement of the vortices. We tested whether the seal used highest velocities, the steepness of the gradients and the spatial extension of the wake in a second set of experiments by varying moving speed and paddle size, respectively. The subject was still able to discriminate between the respective object sizes, but the minimum detectable size difference increased to 4.4. cm (Weber fraction 3.6). For the shape discrimination task, the seal was only able to distinguish flat from triangular paddles. Our results indicate that the seal's discrimination abilities depend on more than one hydrodynamic parameter. Article in Journal/Newspaper harbour seal Phoca vitulina University of Southern Denmark Research Portal Journal of Experimental Biology 214 11 1922 1930 |
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Open Polar |
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University of Southern Denmark Research Portal |
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ftsydanskunivpub |
language |
English |
description |
Harbour seals can use their mystacial vibrissae to detect and track hydrodynamic wakes. We investigated the ability of a harbour seal to discriminate objects of different size or shape by their hydrodynamic signature and used particle image velocimetry to identify the hydrodynamic parameters that a seal may be using to do so. Hydrodynamic trails were generated by different sized or shaped paddles that were moved in the calm water of an experimental box to produce a characteristic signal. In a two-alternative forced-choice procedure the blindfolded subject was able to discriminate size differences of down to 3.6. cm (Weber fraction 0.6) when paddles were moved at the same speed. Furthermore the subject distinguished hydrodynamic signals generated by flat, cylindrical, triangular or undulated paddles of the same width. Particle image velocimetry measurements demonstrated that the seal could have used the highest velocities and the steepness of the gradients within the wake to discriminate object size, beside the size of counter-rotating vortices and the spatial extension of a wake. For shape discrimination the subject could have used the spatial extension of the whole wake, in addition to the arrangement of the vortices. We tested whether the seal used highest velocities, the steepness of the gradients and the spatial extension of the wake in a second set of experiments by varying moving speed and paddle size, respectively. The subject was still able to discriminate between the respective object sizes, but the minimum detectable size difference increased to 4.4. cm (Weber fraction 3.6). For the shape discrimination task, the seal was only able to distinguish flat from triangular paddles. Our results indicate that the seal's discrimination abilities depend on more than one hydrodynamic parameter. |
format |
Article in Journal/Newspaper |
author |
Wieskotten, S. Mauck, B. Miersch, L. Dehnhardt, G. Hanke, W. |
spellingShingle |
Wieskotten, S. Mauck, B. Miersch, L. Dehnhardt, G. Hanke, W. Hydrodynamic discrimination of wakes caused by objects of different size or shape in a harbour seal (Phoca vitulina) |
author_facet |
Wieskotten, S. Mauck, B. Miersch, L. Dehnhardt, G. Hanke, W. |
author_sort |
Wieskotten, S. |
title |
Hydrodynamic discrimination of wakes caused by objects of different size or shape in a harbour seal (Phoca vitulina) |
title_short |
Hydrodynamic discrimination of wakes caused by objects of different size or shape in a harbour seal (Phoca vitulina) |
title_full |
Hydrodynamic discrimination of wakes caused by objects of different size or shape in a harbour seal (Phoca vitulina) |
title_fullStr |
Hydrodynamic discrimination of wakes caused by objects of different size or shape in a harbour seal (Phoca vitulina) |
title_full_unstemmed |
Hydrodynamic discrimination of wakes caused by objects of different size or shape in a harbour seal (Phoca vitulina) |
title_sort |
hydrodynamic discrimination of wakes caused by objects of different size or shape in a harbour seal (phoca vitulina) |
publishDate |
2011 |
url |
https://portal.findresearcher.sdu.dk/da/publications/a1b2b72c-acee-493a-91a3-dd0775f3e7fe https://doi.org/10.1242/jeb.053926 |
genre |
harbour seal Phoca vitulina |
genre_facet |
harbour seal Phoca vitulina |
op_source |
Wieskotten , S , Mauck , B , Miersch , L , Dehnhardt , G & Hanke , W 2011 , ' Hydrodynamic discrimination of wakes caused by objects of different size or shape in a harbour seal (Phoca vitulina) ' , Journal of Experimental Biology , vol. 214 , no. 11 , pp. 1922-1930 . https://doi.org/10.1242/jeb.053926 |
op_relation |
https://portal.findresearcher.sdu.dk/da/publications/a1b2b72c-acee-493a-91a3-dd0775f3e7fe |
op_rights |
info:eu-repo/semantics/restrictedAccess |
op_doi |
https://doi.org/10.1242/jeb.053926 |
container_title |
Journal of Experimental Biology |
container_volume |
214 |
container_issue |
11 |
container_start_page |
1922 |
op_container_end_page |
1930 |
_version_ |
1798847132491317248 |