Amazon river dolphins (Inia geoffrensis) modify biosonar output level and directivity during prey interception in the wild
Toothed whales have evolved to live in extremely different habitats and yet they all rely strongly on echolocation for finding and catching prey. Such biosonar-based foraging involves distinct phases of searching for, approaching and capturing prey, where echolocating animals gradually adjust sonar...
Published in: | Journal of Experimental Biology |
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Main Authors: | , , , , |
Format: | Article in Journal/Newspaper |
Language: | English |
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2017
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Online Access: | https://pure.au.dk/portal/en/publications/37a68cff-6c4d-4d1a-a011-974e8b2e7656 https://doi.org/10.1242/jeb.159913 https://pure.au.dk/ws/files/133621632/Amazon_river_dolphins_Inia_geoffrensis_modify_biosonar_output_level_and_directivity_during_prey_interception_in_the_wild.pdf |
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ftuniaarhuspubl:oai:pure.atira.dk:publications/37a68cff-6c4d-4d1a-a011-974e8b2e7656 2024-01-28T10:07:05+01:00 Amazon river dolphins (Inia geoffrensis) modify biosonar output level and directivity during prey interception in the wild Ladegaard, Michael Jensen, Frants Havmand Beedholm, Kristian Ferreira da Silva, Vera Maria Madsen, Peter Teglberg 2017-07-15 application/pdf https://pure.au.dk/portal/en/publications/37a68cff-6c4d-4d1a-a011-974e8b2e7656 https://doi.org/10.1242/jeb.159913 https://pure.au.dk/ws/files/133621632/Amazon_river_dolphins_Inia_geoffrensis_modify_biosonar_output_level_and_directivity_during_prey_interception_in_the_wild.pdf eng eng https://pure.au.dk/portal/en/publications/37a68cff-6c4d-4d1a-a011-974e8b2e7656 info:eu-repo/semantics/openAccess Ladegaard , M , Jensen , F H , Beedholm , K , Ferreira da Silva , V M & Madsen , P T 2017 , ' Amazon river dolphins (Inia geoffrensis) modify biosonar output level and directivity during prey interception in the wild ' , Journal of Experimental Biology , vol. 220 , no. 14 , pp. 2654-2665 . https://doi.org/10.1242/jeb.159913 Beam pattern Boto Echolocation Gain control Source level Toothed whale BOTTLE-NOSED-DOLPHIN WHALES MESOPLODON-DENSIROSTRIS PORPOISES PHOCOENA-PHOCOENA AUTOMATIC GAIN-CONTROL HIGH-FREQUENCY CLICKS ECHOLOCATION SIGNALS TURSIOPS-TRUNCATUS HARBOR PORPOISES LAGENORHYNCHUS-ALBIROSTRIS STENELLA-FRONTALIS article 2017 ftuniaarhuspubl https://doi.org/10.1242/jeb.159913 2024-01-03T23:59:32Z Toothed whales have evolved to live in extremely different habitats and yet they all rely strongly on echolocation for finding and catching prey. Such biosonar-based foraging involves distinct phases of searching for, approaching and capturing prey, where echolocating animals gradually adjust sonar output to actively shape the flow of sensory information. Measuring those outputs in absolute levels requires hydrophone arrays centred on the biosonar beam axis, but this has never been done for wild toothed whales approaching and capturing prey. Rather, field studies make the assumption that toothed whales will adjust their biosonar in the same manner to arrays as they will when approaching prey. To test this assumption, we recorded wild botos (Inia geoffrensis) as they approached and captured dead fish tethered to a hydrophone in front of a star-shaped seven-hydrophone array. We demonstrate that botos gradually decrease interclick intervals and output levels during prey approaches, using stronger adjustment magnitudes than predicted from previous boto array data. Prey interceptions are characterised by high click rates, but although botos buzz during prey capture, they do so at lower click rates than marine toothed whales, resulting in a much more gradual transition from approach phase to buzzing. We also demonstrate for the first time that wild toothed whales broaden biosonar beamwidth when closing in on prey, as is also seen in captive toothed whales and bats, thus resulting in a larger ensonified volume around the prey, probably aiding prey tracking by decreasing the risk of prey evading ensonification. Article in Journal/Newspaper Lagenorhynchus albirostris Phocoena phocoena toothed whale toothed whales Aarhus University: Research Journal of Experimental Biology |
institution |
Open Polar |
collection |
Aarhus University: Research |
op_collection_id |
ftuniaarhuspubl |
language |
English |
topic |
Beam pattern Boto Echolocation Gain control Source level Toothed whale BOTTLE-NOSED-DOLPHIN WHALES MESOPLODON-DENSIROSTRIS PORPOISES PHOCOENA-PHOCOENA AUTOMATIC GAIN-CONTROL HIGH-FREQUENCY CLICKS ECHOLOCATION SIGNALS TURSIOPS-TRUNCATUS HARBOR PORPOISES LAGENORHYNCHUS-ALBIROSTRIS STENELLA-FRONTALIS |
spellingShingle |
Beam pattern Boto Echolocation Gain control Source level Toothed whale BOTTLE-NOSED-DOLPHIN WHALES MESOPLODON-DENSIROSTRIS PORPOISES PHOCOENA-PHOCOENA AUTOMATIC GAIN-CONTROL HIGH-FREQUENCY CLICKS ECHOLOCATION SIGNALS TURSIOPS-TRUNCATUS HARBOR PORPOISES LAGENORHYNCHUS-ALBIROSTRIS STENELLA-FRONTALIS Ladegaard, Michael Jensen, Frants Havmand Beedholm, Kristian Ferreira da Silva, Vera Maria Madsen, Peter Teglberg Amazon river dolphins (Inia geoffrensis) modify biosonar output level and directivity during prey interception in the wild |
topic_facet |
Beam pattern Boto Echolocation Gain control Source level Toothed whale BOTTLE-NOSED-DOLPHIN WHALES MESOPLODON-DENSIROSTRIS PORPOISES PHOCOENA-PHOCOENA AUTOMATIC GAIN-CONTROL HIGH-FREQUENCY CLICKS ECHOLOCATION SIGNALS TURSIOPS-TRUNCATUS HARBOR PORPOISES LAGENORHYNCHUS-ALBIROSTRIS STENELLA-FRONTALIS |
description |
Toothed whales have evolved to live in extremely different habitats and yet they all rely strongly on echolocation for finding and catching prey. Such biosonar-based foraging involves distinct phases of searching for, approaching and capturing prey, where echolocating animals gradually adjust sonar output to actively shape the flow of sensory information. Measuring those outputs in absolute levels requires hydrophone arrays centred on the biosonar beam axis, but this has never been done for wild toothed whales approaching and capturing prey. Rather, field studies make the assumption that toothed whales will adjust their biosonar in the same manner to arrays as they will when approaching prey. To test this assumption, we recorded wild botos (Inia geoffrensis) as they approached and captured dead fish tethered to a hydrophone in front of a star-shaped seven-hydrophone array. We demonstrate that botos gradually decrease interclick intervals and output levels during prey approaches, using stronger adjustment magnitudes than predicted from previous boto array data. Prey interceptions are characterised by high click rates, but although botos buzz during prey capture, they do so at lower click rates than marine toothed whales, resulting in a much more gradual transition from approach phase to buzzing. We also demonstrate for the first time that wild toothed whales broaden biosonar beamwidth when closing in on prey, as is also seen in captive toothed whales and bats, thus resulting in a larger ensonified volume around the prey, probably aiding prey tracking by decreasing the risk of prey evading ensonification. |
format |
Article in Journal/Newspaper |
author |
Ladegaard, Michael Jensen, Frants Havmand Beedholm, Kristian Ferreira da Silva, Vera Maria Madsen, Peter Teglberg |
author_facet |
Ladegaard, Michael Jensen, Frants Havmand Beedholm, Kristian Ferreira da Silva, Vera Maria Madsen, Peter Teglberg |
author_sort |
Ladegaard, Michael |
title |
Amazon river dolphins (Inia geoffrensis) modify biosonar output level and directivity during prey interception in the wild |
title_short |
Amazon river dolphins (Inia geoffrensis) modify biosonar output level and directivity during prey interception in the wild |
title_full |
Amazon river dolphins (Inia geoffrensis) modify biosonar output level and directivity during prey interception in the wild |
title_fullStr |
Amazon river dolphins (Inia geoffrensis) modify biosonar output level and directivity during prey interception in the wild |
title_full_unstemmed |
Amazon river dolphins (Inia geoffrensis) modify biosonar output level and directivity during prey interception in the wild |
title_sort |
amazon river dolphins (inia geoffrensis) modify biosonar output level and directivity during prey interception in the wild |
publishDate |
2017 |
url |
https://pure.au.dk/portal/en/publications/37a68cff-6c4d-4d1a-a011-974e8b2e7656 https://doi.org/10.1242/jeb.159913 https://pure.au.dk/ws/files/133621632/Amazon_river_dolphins_Inia_geoffrensis_modify_biosonar_output_level_and_directivity_during_prey_interception_in_the_wild.pdf |
genre |
Lagenorhynchus albirostris Phocoena phocoena toothed whale toothed whales |
genre_facet |
Lagenorhynchus albirostris Phocoena phocoena toothed whale toothed whales |
op_source |
Ladegaard , M , Jensen , F H , Beedholm , K , Ferreira da Silva , V M & Madsen , P T 2017 , ' Amazon river dolphins (Inia geoffrensis) modify biosonar output level and directivity during prey interception in the wild ' , Journal of Experimental Biology , vol. 220 , no. 14 , pp. 2654-2665 . https://doi.org/10.1242/jeb.159913 |
op_relation |
https://pure.au.dk/portal/en/publications/37a68cff-6c4d-4d1a-a011-974e8b2e7656 |
op_rights |
info:eu-repo/semantics/openAccess |
op_doi |
https://doi.org/10.1242/jeb.159913 |
container_title |
Journal of Experimental Biology |
_version_ |
1789334431762219008 |