Dolphin echolocation behaviour during active long-range target approaches
Echolocating toothed whales generally adjust click intensity and rate according to target range to ensure that echoes from targets of interest arrive before a subsequent click is produced, presumably facilitating range estimation from the delay between clicks and returning echoes. However, this clic...
Published in: | Journal of Experimental Biology |
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fthighwire:oai:open-archive.highwire.org:jexbio:222/2/jeb189217 2023-05-15T18:33:32+02:00 Dolphin echolocation behaviour during active long-range target approaches Ladegaard, Michael Mulsow, Jason Houser, Dorian S. Jensen, Frants Havmand Johnson, Mark Madsen, Peter Teglberg Finneran, James J. 2019-01-25 01:28:50.0 text/html http://jeb.biologists.org/cgi/content/short/222/2/jeb189217 https://doi.org/10.1242/jeb.189217 en eng The Company of Biologists Ltd http://jeb.biologists.org/cgi/content/short/222/2/jeb189217 http://dx.doi.org/10.1242/jeb.189217 Copyright (C) 2019, Company of Biologists RESEARCH ARTICLE TEXT 2019 fthighwire https://doi.org/10.1242/jeb.189217 2019-02-10T09:40:03Z Echolocating toothed whales generally adjust click intensity and rate according to target range to ensure that echoes from targets of interest arrive before a subsequent click is produced, presumably facilitating range estimation from the delay between clicks and returning echoes. However, this click–echo–click paradigm for the dolphin biosonar is mostly based on experiments with stationary animals echolocating fixed targets at ranges below ∼120 m. Therefore, we trained two bottlenose dolphins instrumented with a sound recording tag to approach a target from ranges up to 400 m and either touch the target (subject TRO) or detect a target orientation change (subject SAY). We show that free-swimming dolphins dynamically increase interclick interval (ICI) out to target ranges of ∼100 m. TRO consistently kept ICIs above the two-way travel time (TWTT) for target ranges shorter than ∼100 m, whereas SAY switched between clicking at ICIs above and below the TWTT for target ranges down to ∼25 m. Source levels changed on average by 17log 10 (target range), but with considerable variation for individual slopes (4.1 standard deviations for by-trial random effects), demonstrating that dolphins do not adopt a fixed automatic gain control matched to target range. At target ranges exceeding ∼100 m, both dolphins frequently switched to click packet production in which interpacket intervals exceeded the TWTT, but ICIs were shorter than the TWTT. We conclude that the click–echo–click paradigm is not a fixed echolocation strategy in dolphins, and we demonstrate the first use of click packets for free-swimming dolphins when solving an echolocation task. Text toothed whales HighWire Press (Stanford University) Journal of Experimental Biology |
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HighWire Press (Stanford University) |
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English |
topic |
RESEARCH ARTICLE |
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RESEARCH ARTICLE Ladegaard, Michael Mulsow, Jason Houser, Dorian S. Jensen, Frants Havmand Johnson, Mark Madsen, Peter Teglberg Finneran, James J. Dolphin echolocation behaviour during active long-range target approaches |
topic_facet |
RESEARCH ARTICLE |
description |
Echolocating toothed whales generally adjust click intensity and rate according to target range to ensure that echoes from targets of interest arrive before a subsequent click is produced, presumably facilitating range estimation from the delay between clicks and returning echoes. However, this click–echo–click paradigm for the dolphin biosonar is mostly based on experiments with stationary animals echolocating fixed targets at ranges below ∼120 m. Therefore, we trained two bottlenose dolphins instrumented with a sound recording tag to approach a target from ranges up to 400 m and either touch the target (subject TRO) or detect a target orientation change (subject SAY). We show that free-swimming dolphins dynamically increase interclick interval (ICI) out to target ranges of ∼100 m. TRO consistently kept ICIs above the two-way travel time (TWTT) for target ranges shorter than ∼100 m, whereas SAY switched between clicking at ICIs above and below the TWTT for target ranges down to ∼25 m. Source levels changed on average by 17log 10 (target range), but with considerable variation for individual slopes (4.1 standard deviations for by-trial random effects), demonstrating that dolphins do not adopt a fixed automatic gain control matched to target range. At target ranges exceeding ∼100 m, both dolphins frequently switched to click packet production in which interpacket intervals exceeded the TWTT, but ICIs were shorter than the TWTT. We conclude that the click–echo–click paradigm is not a fixed echolocation strategy in dolphins, and we demonstrate the first use of click packets for free-swimming dolphins when solving an echolocation task. |
format |
Text |
author |
Ladegaard, Michael Mulsow, Jason Houser, Dorian S. Jensen, Frants Havmand Johnson, Mark Madsen, Peter Teglberg Finneran, James J. |
author_facet |
Ladegaard, Michael Mulsow, Jason Houser, Dorian S. Jensen, Frants Havmand Johnson, Mark Madsen, Peter Teglberg Finneran, James J. |
author_sort |
Ladegaard, Michael |
title |
Dolphin echolocation behaviour during active long-range target approaches |
title_short |
Dolphin echolocation behaviour during active long-range target approaches |
title_full |
Dolphin echolocation behaviour during active long-range target approaches |
title_fullStr |
Dolphin echolocation behaviour during active long-range target approaches |
title_full_unstemmed |
Dolphin echolocation behaviour during active long-range target approaches |
title_sort |
dolphin echolocation behaviour during active long-range target approaches |
publisher |
The Company of Biologists Ltd |
publishDate |
2019 |
url |
http://jeb.biologists.org/cgi/content/short/222/2/jeb189217 https://doi.org/10.1242/jeb.189217 |
genre |
toothed whales |
genre_facet |
toothed whales |
op_relation |
http://jeb.biologists.org/cgi/content/short/222/2/jeb189217 http://dx.doi.org/10.1242/jeb.189217 |
op_rights |
Copyright (C) 2019, Company of Biologists |
op_doi |
https://doi.org/10.1242/jeb.189217 |
container_title |
Journal of Experimental Biology |
_version_ |
1766218160557522944 |