Context-dependent biosonar adjustments during active target approaches in echolocating harbour porpoises
Echolocating mammals generally target individual prey items by transitioning through the biosonar phases of search (slow-rate, high-amplitude outputs), approach (gradually increasing rate and decreasing output amplitude) and buzzing (high-rate, low-amplitude outputs). The range to the main target of...
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fthighwire:oai:open-archive.highwire.org:jexbio:222/16/jeb206169 2023-05-15T18:33:32+02:00 Context-dependent biosonar adjustments during active target approaches in echolocating harbour porpoises Ladegaard, Michael Madsen, Peter Teglberg 2019-08-19 01:44:04.0 text/html http://jeb.biologists.org/cgi/content/short/222/16/jeb206169 https://doi.org/10.1242/jeb.206169 en eng The Company of Biologists Ltd http://jeb.biologists.org/cgi/content/short/222/16/jeb206169 http://dx.doi.org/10.1242/jeb.206169 Copyright (C) 2019, Company of Biologists RESEARCH ARTICLE TEXT 2019 fthighwire https://doi.org/10.1242/jeb.206169 2019-10-03T17:08:28Z Echolocating mammals generally target individual prey items by transitioning through the biosonar phases of search (slow-rate, high-amplitude outputs), approach (gradually increasing rate and decreasing output amplitude) and buzzing (high-rate, low-amplitude outputs). The range to the main target of interest is often considered the key or sole driver of such biosonar adjustments of acoustic gaze. However, the actively generated auditory scene of an echolocator invariably comprises a large number of other reflectors and noise sources that likely also impact the biosonar strategies and source parameters implemented by an echolocating animal in time and space. In toothed whales, the importance of context on biosonar adjustments is largely unknown. To address this, we trained two harbour porpoises to actively approach the same sound recording target over the same approach distance in two highly different environments: a PVC-lined pool and a semi-natural net pen in a harbour, while blind-folded and wearing a sound recording tag (DTAG-4). We show that the approaching porpoises used considerably shorter interclick intervals (ICIs) in the pool than in the net pen, except during the buzz phase, where slightly longer ICIs were used in the pool. We further show that average click source levels were 4–7 dB higher in the net pen. Because of the very low-level in-band ambient noise in both environments, we posit that the porpoises adapted their echolocation strategy to the different reverberation levels between the two settings. We demonstrate that harbour porpoises use different echolocation strategies and biosonar parameters in two different environments for solving an otherwise identical target approach task and thus highlight that biosonar adjustments are both range and context dependent. Text toothed whales HighWire Press (Stanford University) Journal of Experimental Biology |
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HighWire Press (Stanford University) |
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RESEARCH ARTICLE |
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RESEARCH ARTICLE Ladegaard, Michael Madsen, Peter Teglberg Context-dependent biosonar adjustments during active target approaches in echolocating harbour porpoises |
topic_facet |
RESEARCH ARTICLE |
description |
Echolocating mammals generally target individual prey items by transitioning through the biosonar phases of search (slow-rate, high-amplitude outputs), approach (gradually increasing rate and decreasing output amplitude) and buzzing (high-rate, low-amplitude outputs). The range to the main target of interest is often considered the key or sole driver of such biosonar adjustments of acoustic gaze. However, the actively generated auditory scene of an echolocator invariably comprises a large number of other reflectors and noise sources that likely also impact the biosonar strategies and source parameters implemented by an echolocating animal in time and space. In toothed whales, the importance of context on biosonar adjustments is largely unknown. To address this, we trained two harbour porpoises to actively approach the same sound recording target over the same approach distance in two highly different environments: a PVC-lined pool and a semi-natural net pen in a harbour, while blind-folded and wearing a sound recording tag (DTAG-4). We show that the approaching porpoises used considerably shorter interclick intervals (ICIs) in the pool than in the net pen, except during the buzz phase, where slightly longer ICIs were used in the pool. We further show that average click source levels were 4–7 dB higher in the net pen. Because of the very low-level in-band ambient noise in both environments, we posit that the porpoises adapted their echolocation strategy to the different reverberation levels between the two settings. We demonstrate that harbour porpoises use different echolocation strategies and biosonar parameters in two different environments for solving an otherwise identical target approach task and thus highlight that biosonar adjustments are both range and context dependent. |
format |
Text |
author |
Ladegaard, Michael Madsen, Peter Teglberg |
author_facet |
Ladegaard, Michael Madsen, Peter Teglberg |
author_sort |
Ladegaard, Michael |
title |
Context-dependent biosonar adjustments during active target approaches in echolocating harbour porpoises |
title_short |
Context-dependent biosonar adjustments during active target approaches in echolocating harbour porpoises |
title_full |
Context-dependent biosonar adjustments during active target approaches in echolocating harbour porpoises |
title_fullStr |
Context-dependent biosonar adjustments during active target approaches in echolocating harbour porpoises |
title_full_unstemmed |
Context-dependent biosonar adjustments during active target approaches in echolocating harbour porpoises |
title_sort |
context-dependent biosonar adjustments during active target approaches in echolocating harbour porpoises |
publisher |
The Company of Biologists Ltd |
publishDate |
2019 |
url |
http://jeb.biologists.org/cgi/content/short/222/16/jeb206169 https://doi.org/10.1242/jeb.206169 |
genre |
toothed whales |
genre_facet |
toothed whales |
op_relation |
http://jeb.biologists.org/cgi/content/short/222/16/jeb206169 http://dx.doi.org/10.1242/jeb.206169 |
op_rights |
Copyright (C) 2019, Company of Biologists |
op_doi |
https://doi.org/10.1242/jeb.206169 |
container_title |
Journal of Experimental Biology |
_version_ |
1766218167155163136 |