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Hao X, Hamel H, Grandjean CH, Fedutin I, Wahlberg M, Frankish CK, Nabe‐Nielsen J. Harbour porpoises respond to recreational boats by speeding up and moving away from the boat path. Ecol Evol 2024; 14:e11433. [PMID: 38756690 PMCID: PMC11096697 DOI: 10.1002/ece3.11433] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2024] [Revised: 04/18/2024] [Accepted: 05/02/2024] [Indexed: 05/18/2024] Open
Abstract
Recreational boats are common in many coastal waters, yet their effects on cetaceans and other sensitive marine species remain poorly understood. To address this knowledge gap, we used drone video footage recorded from a recreational boat to quantify how harbour porpoises (Phocoena phocoena) responded to the boat approaching at different speeds (10 or 20 knots). Furthermore, we used a hydrophone to record boat noise levels at full bandwidth (0.1-150 kHz) and at the 1/3 octave 16 kHz frequency band for both experimental speeds. The experiments were carried out in shallow waters near Funen, Denmark (55.51° N, 10.79° E) between July and September 2022. Porpoises were more likely to move further away from the path of the boat when approached at 10 knots, but not when approached at 20 knots. In contrast, they swam faster when approached at 20 knots, but not when approached at 10 knots. The recorded received sound level did not depend on how fast the boat approached, suggesting that differences in porpoise responses were related to the speed of the approaching boat rather than to sound intensity. In addition, porpoises generally reacted within close proximity (<200 m) to the approaching boat and quickly (<50 s) resumed their natural behaviour once the boat had passed, indicating that the direct impact of small vessels on porpoise behaviour was most likely small. Nevertheless, repeated exposure to noise from small vessels may influence porpoises' activity or energy budget, and cause them to relocate from disturbed areas. The approach used in this study increases our understanding of recreational boats' impact on harbour porpoises and can be used to inform efficient mitigation measures to help focus conservation efforts.
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Affiliation(s)
- Xiuqing Hao
- Department of EcoscienceAarhus UniversityRoskildeDenmark
| | - Héloïse Hamel
- Department of BiologyUniversity of Southern DenmarkOdenseDenmark
| | | | | | - Magnus Wahlberg
- Department of BiologyUniversity of Southern DenmarkOdenseDenmark
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Elemans CPH, Jiang W, Jensen MH, Pichler H, Mussman BR, Nattestad J, Wahlberg M, Zheng X, Xue Q, Fitch WT. Evolutionary novelties underlie sound production in baleen whales. Nature 2024; 627:123-129. [PMID: 38383781 DOI: 10.1038/s41586-024-07080-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2023] [Accepted: 01/16/2024] [Indexed: 02/23/2024]
Abstract
Baleen whales (mysticetes) use vocalizations to mediate their complex social and reproductive behaviours in vast, opaque marine environments1. Adapting to an obligate aquatic lifestyle demanded fundamental physiological changes to efficiently produce sound, including laryngeal specializations2-4. Whereas toothed whales (odontocetes) evolved a nasal vocal organ5, mysticetes have been thought to use the larynx for sound production1,6-8. However, there has been no direct demonstration that the mysticete larynx can phonate, or if it does, how it produces the great diversity of mysticete sounds9. Here we combine experiments on the excised larynx of three mysticete species with detailed anatomy and computational models to show that mysticetes evolved unique laryngeal structures for sound production. These structures allow some of the largest animals that ever lived to efficiently produce frequency-modulated, low-frequency calls. Furthermore, we show that this phonation mechanism is likely to be ancestral to all mysticetes and shares its fundamental physical basis with most terrestrial mammals, including humans10, birds11, and their closest relatives, odontocetes5. However, these laryngeal structures set insurmountable physiological limits to the frequency range and depth of their vocalizations, preventing them from escaping anthropogenic vessel noise12,13 and communicating at great depths14, thereby greatly reducing their active communication range.
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Affiliation(s)
- Coen P H Elemans
- Sound Communication and Behaviour Group, Department of Biology, University of Southern Denmark, Odense, Denmark.
| | - Weili Jiang
- Department of Mechanical Engineering, Rochester Institute of Technology, Rochester, NY, USA
| | - Mikkel H Jensen
- Sound Communication and Behaviour Group, Department of Biology, University of Southern Denmark, Odense, Denmark
| | - Helena Pichler
- Department of Behavioral and Cognitive Biology, Faculty of Life Sciences, University of Vienna, Vienna, Austria
| | - Bo R Mussman
- Department of Radiology, Odense University Hospital, Odense, Denmark
- Department of Clinical Research, University of Southern Denmark, Odense, Denmark
| | - Jacob Nattestad
- Department of Radiology, Odense University Hospital, Odense, Denmark
| | - Magnus Wahlberg
- Sound Communication and Behaviour Group, Department of Biology, University of Southern Denmark, Odense, Denmark
| | - Xudong Zheng
- Department of Mechanical Engineering, Rochester Institute of Technology, Rochester, NY, USA
| | - Qian Xue
- Department of Mechanical Engineering, Rochester Institute of Technology, Rochester, NY, USA
| | - W Tecumseh Fitch
- Department of Behavioral and Cognitive Biology, Faculty of Life Sciences, University of Vienna, Vienna, Austria.
- Vienna Cognitive Science Hub, University of Vienna, Vienna, Austria.
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3
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Stepien EN, Galatius A, Hansen KA, Nabe-Nielsen J, Teilmann J, Wahlberg M. Response of Eurasian otters (Lutra lutra) to underwater acoustic harassment device sounds. Sci Rep 2024; 14:4988. [PMID: 38424202 PMCID: PMC10904746 DOI: 10.1038/s41598-024-55481-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2023] [Accepted: 02/23/2024] [Indexed: 03/02/2024] Open
Abstract
Seal scarers (or acoustic harassment devices, AHDs) are designed to deter seals from fishing gear and aquaculture operations, as well as to prevent seals from entering rivers to avoid predation on valuable fish. Our study investigated the potential effects of AHDs on non-target species, specifically the Eurasian otters (Lutra lutra), by testing the reaction of two rehabilitated otters to simulated AHDs sounds at 1 and 14 kHz, with a received sound intensity of 105-145 dB re 1 µPa rms. The 1 kHz sounds were used to investigate alternative frequencies for scaring seals without scaring otters. The otters reacted to both 1 and 14 kHz tonal signals when retrieving fish from a feeding station 0.8 m below the surface. Their diving behaviour and time to extract food progressively increased as sound intensity increased for all tested sound levels. Notably, the sound levels used in our tests were significantly lower (40-80 dB) than the source levels from commercial AHDs. These findings highlight the importance of caution when using AHDs in river and sea habitats inhabited by otters, as AHDs can change their behaviour and potentially result in habitat exclusion.
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Affiliation(s)
| | - Anders Galatius
- Marine Mammal Research, Department of Ecoscience, Aarhus University, Aarhus, Denmark
| | - Kirstin Anderson Hansen
- Marine Biological Research Centre, Department of Biology, University of Southern Denmark, Odense, Denmark
| | - Jacob Nabe-Nielsen
- Marine Mammal Research, Department of Ecoscience, Aarhus University, Aarhus, Denmark
| | - Jonas Teilmann
- Marine Mammal Research, Department of Ecoscience, Aarhus University, Aarhus, Denmark
| | - Magnus Wahlberg
- Marine Biological Research Centre, Department of Biology, University of Southern Denmark, Odense, Denmark
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4
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Abildtrup Nielsen N, Dawson SM, Torres Ortiz S, Wahlberg M, Martin MJ. Hector's dolphins (Cephalorhynchus hectori) produce both narrowband high-frequency and broadband acoustic signals. J Acoust Soc Am 2024; 155:1437-1450. [PMID: 38364047 DOI: 10.1121/10.0024820] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2023] [Accepted: 01/25/2024] [Indexed: 02/18/2024]
Abstract
Odontocetes produce clicks for echolocation and communication. Most odontocetes are thought to produce either broadband (BB) or narrowband high-frequency (NBHF) clicks. Here, we show that the click repertoire of Hector's dolphin (Cephalorhynchus hectori) comprises highly stereotypical NBHF clicks and far more variable broadband clicks, with some that are intermediate between these two categories. Both NBHF and broadband clicks were made in trains, buzzes, and burst-pulses. Most clicks within click trains were typical NBHF clicks, which had a median centroid frequency of 130.3 kHz (median -10 dB bandwidth = 29.8 kHz). Some, however, while having only marginally lower centroid frequency (median = 123.8 kHz), had significant energy below 100 kHz and approximately double the bandwidth (median -10 dB bandwidth = 69.8 kHz); we refer to these as broadband. Broadband clicks in buzzes and burst-pulses had lower median centroid frequencies (120.7 and 121.8 kHz, respectively) compared to NBHF buzzes and burst-pulses (129.5 and 130.3 kHz, respectively). Source levels of NBHF clicks, estimated by using a drone to measure ranges from a single hydrophone and by computing time-of-arrival differences at a vertical hydrophone array, ranged from 116 to 171 dB re 1 μPa at 1 m, whereas source levels of broadband clicks, obtained from array data only, ranged from 138 to 184 dB re 1 μPa at 1 m. Our findings challenge the grouping of toothed whales as either NBHF or broadband species.
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Affiliation(s)
- Nicoline Abildtrup Nielsen
- Marine Biological Research Center, Department of Biology, University of Southern Denmark, 5300 Kerteminde, Denmark
| | - Stephen M Dawson
- Department of Marine Science, University of Otago, Dunedin 9054, New Zealand
| | - Sara Torres Ortiz
- Marine Biological Research Center, Department of Biology, University of Southern Denmark, 5300 Kerteminde, Denmark
| | - Magnus Wahlberg
- Marine Biological Research Center, Department of Biology, University of Southern Denmark, 5300 Kerteminde, Denmark
| | - Morgan J Martin
- Center for Marine Acoustics, Bureau of Ocean Energy Management, Sterling, Virginia 20166, USA
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Tidière M, Colchero F, Staerk J, Adkesson MJ, Andersen DH, Bland L, Böye M, Brando S, Clegg I, Cubaynes S, Cutting A, De Man D, Derocher AE, Dorsey C, Elgar W, Gaglione E, Anderson Hansen K, Jungheim A, Kok J, Laule G, Goya AL, Miller L, Monreal-Pawlowsky T, Mucha K, Owen MA, Petersen SD, Pilfold N, Richardson D, Richardson ES, Sabo D, Sato N, Shellabarger W, Skovlund CR, Tomisawa K, Trautwein SE, Van Bonn W, Van Elk C, Von Fersen L, Wahlberg M, Zhang P, Zhang X, Conde DA. Survival improvements of marine mammals in zoological institutions mirror historical advances in human longevity. Proc Biol Sci 2023; 290:20231895. [PMID: 37848064 PMCID: PMC10581765 DOI: 10.1098/rspb.2023.1895] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2023] [Accepted: 09/21/2023] [Indexed: 10/19/2023] Open
Abstract
An intense public debate has fuelled governmental bans on marine mammals held in zoological institutions. The debate rests on the assumption that survival in zoological institutions has been and remains lower than in the wild, albeit the scientific evidence in support of this notion is equivocal. Here, we used statistical methods previously applied to assess historical improvements in human lifespan and data on 8864 individuals of four marine mammal species (harbour seal, Phoca vitulina; California sea lion, Zalophus californianus; polar bear, Ursus maritimus; common bottlenose dolphin, Tursiops truncatus) held in zoos from 1829 to 2020. We found that life expectancy increased up to 3.40 times, and first-year mortality declined up to 31%, during the last century in zoos. Moreover, the life expectancy of animals in zoos is currently 1.65-3.55 times longer than their wild counterparts. Like humans, these improvements have occurred concurrently with advances in management practices, crucial for population welfare. Science-based decisions will help effective legislative changes and ensure better implementation of animal care.
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Affiliation(s)
- Morgane Tidière
- Interdisciplinary Centre on Population Dynamics (CPop), University of Southern Denmark, Odense, Denmark
- Department of Biology, University of Southern Denmark, Campusvej 55, 5230 Odense, Denmark
- Conservation and Science Department, Species360, 7900 International Drive, Suite 300, Minneapolis, MN 55425, USA
| | - Fernando Colchero
- Interdisciplinary Centre on Population Dynamics (CPop), University of Southern Denmark, Odense, Denmark
- Department of Mathematics and Computer Science, University of Southern Denmark, Odense, Denmark
- Department of Primate Behavior and Evolution, Max Planck Institute for Evolutionary Anthropology, Deutscher Pl. 6, 04103 Leipzig, Germany
| | - Johanna Staerk
- Interdisciplinary Centre on Population Dynamics (CPop), University of Southern Denmark, Odense, Denmark
- Department of Biology, University of Southern Denmark, Campusvej 55, 5230 Odense, Denmark
- Conservation and Science Department, Species360, 7900 International Drive, Suite 300, Minneapolis, MN 55425, USA
| | | | - Ditte H. Andersen
- Department of Biology, University of Southern Denmark, Campusvej 55, 5230 Odense, Denmark
| | - Lucie Bland
- Conservation and Science Department, Species360, 7900 International Drive, Suite 300, Minneapolis, MN 55425, USA
- Eureka Publishing, Thornbury, Australia
| | - Martin Böye
- Centre de Recherche et d'Etude pour l'Animal Sauvage, Planète Sauvage, 44710 Port Saint Pere, France
| | - Sabrina Brando
- AnimalConcepts, PO Box 378, 03725 Teulada, Alicante, Spain
| | - Isabella Clegg
- Animal Welfare Expertise, The Knoll, Woodlands, Combe Martin, EX34 0ATLittleton Manor, Winchester SO22 6QU, UK
| | - Sarah Cubaynes
- CEFE, Univ Montpellier, CNRS, EPHE-PSL University, IRD, Montpellier, France
| | - Amy Cutting
- Polar Bear International, PO Box 3008, Bozeman, MT, USA
| | - Danny De Man
- European Association of Zoos and Aquaria (EAZA), Plantage Middelaan 45, 1018-DC Amsterdam, The Netherlands
| | - Andrew E. Derocher
- Department of Biological Sciences, University of Alberta; Edmonton, Alberta, Canada T6G 2E9
| | - Candice Dorsey
- Association of Zoos and Aquariums, 8403 Colesville Road Ste 710, Silver Spring, MD 20910, USA
| | - William Elgar
- Zoo Miami, 12400 SW 152 Street, Miami, FL 33177, USA
| | - Eric Gaglione
- Georgia Aquarium, 225 Baker Street, Atlanta, GA 30313, USA
| | - Kirstin Anderson Hansen
- Department of Biology, University of Southern Denmark, Campusvej 55, 5230 Odense, Denmark
- Marine Biological Research Center, University of Southern Denmark, Hindsholmvej 11, 5300 Kerteminde, Denmark
| | - Allison Jungheim
- Como Park Zoo and Conservatory, 1225 Estabrook Dr., Saint Paul, MN 55103, USA
| | - José Kok
- Ouwehands Zoo, Grebbeweg 111, 3911 AV Rhenen, The Netherlands
| | - Gail Laule
- Mandai Wildlife Group, 80 Mandai Lake Road, Singapore 729826
| | | | - Lance Miller
- Chicago Zoological Society, Brookfield Zoo, Brookfield, IL, USA
| | | | - Katelyn Mucha
- Conservation and Science Department, Species360, 7900 International Drive, Suite 300, Minneapolis, MN 55425, USA
| | - Megan A. Owen
- San Diego Zoo Wildlife Alliance, 15600 San Pasqual Valley Rd., Escondido, CA, USA
| | | | - Nicholas Pilfold
- San Diego Zoo Wildlife Alliance, 15600 San Pasqual Valley Rd., Escondido, CA, USA
| | - Douglas Richardson
- Zoological Consultancy Ltd, Columba Cottage, Mill Rd, Kingussie PH21 1LF, UK
- EAZA Polar Bear EEP, Amsterdam, Netherlands
| | - Evan S. Richardson
- Environment and Climate Change Canada, Unit 150–234 Donald Street, Winnipeg, Manitoba R3C 1M8, Canada
| | - Devon Sabo
- Columbus Zoo and Aquarium, 4850 W. Powell Road, PO Box 400, Powell, OH 43065-0400, USA
| | - Nobutaka Sato
- Asahiyama Zoological Park, Kuranuma, Higasiasahikawacho, Asahikawa city, Japan
| | | | - Cecilie R. Skovlund
- Conservation, Copenhagen Zoo, Roskildevej 38, 2000 Frederiksberg, Denmark
- Section of Animal Welfare and Disease Control, Department of Veterinary and Animal Sciences, University of Copenhagen, Grønnegårdsvej 8, 1870 Frederiksberg, Denmark
| | - Kanako Tomisawa
- Omuta City Zoo, 163 Showa-machi, Omuta, Fukuoka 836-0871, Japan
| | - Sandra E. Trautwein
- Conservation and Science Department, Species360, 7900 International Drive, Suite 300, Minneapolis, MN 55425, USA
| | - William Van Bonn
- A. Watson Armour III, Center for Animal Health and Welfare, Animal Care and Science Division, John G. Shedd Aquarium, Chicago, IL 60605, USA
| | - Cornelis Van Elk
- Independent practitioner, Arendsweg 98, Enschede 7544RM, The Netherlands
| | | | - Magnus Wahlberg
- Department of Biology, University of Southern Denmark, Campusvej 55, 5230 Odense, Denmark
- Marine Biological Research Center, University of Southern Denmark, Hindsholmvej 11, 5300 Kerteminde, Denmark
| | - Peijun Zhang
- Mammal and Marine Bioacoustics Laboratory Institute of Deep-sea Science and Engineering, Chinese Academy of Sciences, Sanya 572000, People's Republic of China
| | - Xianfeng Zhang
- Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, People's Republic of China
| | - Dalia A. Conde
- Interdisciplinary Centre on Population Dynamics (CPop), University of Southern Denmark, Odense, Denmark
- Department of Biology, University of Southern Denmark, Campusvej 55, 5230 Odense, Denmark
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Elmegaard SL, Teilmann J, Rojano-Doñate L, Brennecke D, Mikkelsen L, Balle JD, Gosewinkel U, Kyhn LA, Tønnesen P, Wahlberg M, Ruser A, Siebert U, Madsen PT. Wild harbour porpoises startle and flee at low received levels from acoustic harassment device. Sci Rep 2023; 13:16691. [PMID: 37794093 PMCID: PMC10550999 DOI: 10.1038/s41598-023-43453-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2022] [Accepted: 09/24/2023] [Indexed: 10/06/2023] Open
Abstract
Acoustic Harassment Devices (AHD) are widely used to deter marine mammals from aquaculture depredation, and from pile driving operations that may otherwise cause hearing damage. However, little is known about the behavioural and physiological effects of these devices. Here, we investigate the physiological and behavioural responses of harbour porpoises (Phocoena phocoena) to a commercial AHD in Danish waters. Six porpoises were tagged with suction-cup-attached DTAGs recording sound, 3D-movement, and GPS (n = 3) or electrocardiogram (n = 2). They were then exposed to AHDs for 15 min, with initial received levels (RL) ranging from 98 to 132 dB re 1 µPa (rms-fast, 125 ms) and initial exposure ranges of 0.9-7 km. All animals reacted by displaying a mixture of acoustic startle responses, fleeing, altered echolocation behaviour, and by demonstrating unusual tachycardia while diving. Moreover, during the 15-min exposures, half of the animals received cumulative sound doses close to published thresholds for temporary auditory threshold shifts. We conclude that AHD exposure at many km can evoke both startle, flight and cardiac responses which may impact blood-gas management, breath-hold capability, energy balance, stress level and risk of by-catch. We posit that current AHDs are too powerful for mitigation use to prevent hearing damage of porpoises from offshore construction.
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Affiliation(s)
- Siri L Elmegaard
- Zoophysiology, Dept. of Biology, Aarhus University, 8000, Aarhus, Denmark.
- Marine Mammal Research, Dept. of Ecoscience, Aarhus University, 4000, Roskilde, Denmark.
| | - Jonas Teilmann
- Marine Mammal Research, Dept. of Ecoscience, Aarhus University, 4000, Roskilde, Denmark
| | - Laia Rojano-Doñate
- Zoophysiology, Dept. of Biology, Aarhus University, 8000, Aarhus, Denmark
- Marine Mammal Research, Dept. of Ecoscience, Aarhus University, 4000, Roskilde, Denmark
| | - Dennis Brennecke
- Institute for Terrestrial and Aquatic Wildlife Research, University of Veterinary Medicine Hannover, Foundation, 25761, Büsum, Germany
| | - Lonnie Mikkelsen
- Marine Mammal Research, Dept. of Ecoscience, Aarhus University, 4000, Roskilde, Denmark
- Norwegian Polar Institute, 9296, Tromsø, Norway
| | - Jeppe D Balle
- Marine Mammal Research, Dept. of Ecoscience, Aarhus University, 4000, Roskilde, Denmark
| | - Ulrich Gosewinkel
- Environmental Microbiology, Dept. of Environmental Science, Aarhus University, 4000, Roskilde, Denmark
| | - Line A Kyhn
- Marine Mammal Research, Dept. of Ecoscience, Aarhus University, 4000, Roskilde, Denmark
| | - Pernille Tønnesen
- Zoophysiology, Dept. of Biology, Aarhus University, 8000, Aarhus, Denmark
| | - Magnus Wahlberg
- Marine Biological Research Centre, Dept. of Biology, University of Southern Denmark, 5300, Kerteminde, Denmark
| | - Andreas Ruser
- Institute for Terrestrial and Aquatic Wildlife Research, University of Veterinary Medicine Hannover, Foundation, 25761, Büsum, Germany
| | - Ursula Siebert
- Institute for Terrestrial and Aquatic Wildlife Research, University of Veterinary Medicine Hannover, Foundation, 25761, Büsum, Germany
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Baier-Stegmaier S, Gundlach C, Chriél M, Hansen MS, Vedel-Smith C, Hansen CV, Johansson DK, Henriksen LB, Wahlberg M, Thøstesen CB, Alstrup AKO, Gregersen KM, Pertoldi C, Pagh S. Computed Tomography as a Method for Age Determination of Carnivora and Odontocetes with Validation from Individuals with Known Age. Animals (Basel) 2023; 13:1783. [PMID: 37889740 PMCID: PMC10251996 DOI: 10.3390/ani13111783] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2023] [Revised: 05/19/2023] [Accepted: 05/24/2023] [Indexed: 10/29/2023] Open
Abstract
Traditional methods for age determination of wildlife include either slicing thin sections off or grinding a tooth, both of which are laborious and invasive. Especially when it comes to ancient and valuable museum samples of rare or extinct species, non-invasive methods are preferable. In this study, X-ray micro-computed tomography (µ-CT) was verified as an alternative non-invasive method for age determination of three species within the order of Carnivora and suborders Odontoceti. Teeth from 13 red foxes (Vulpes vulpes), 2 American mink (Neogale vison), and 2 harbor porpoises (Phocoena phocoena) of known age were studied using µ-CT. The number of visible dental growth layers in the µ-CT were highly correlated with true age for all three species (R2 = 96%, p < 0.001). In addition, the Bland-Altman plot showed high agreement between the age of individuals and visible dental layers represented in 2D slices of the 3D µ-CT images. The true age of individuals was on average 0.3 (±0.6 SD) years higher than the age interpreted by the µ-CT image, and there was a 95% agreement between the true age and the age interpreted from visible dental layers in the µ-CT.
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Affiliation(s)
- Sina Baier-Stegmaier
- Department of Physics, Technical University of Denmark, 2800 Kongens Lyngby, Denmark; (S.B.-S.)
| | - Carsten Gundlach
- Department of Physics, Technical University of Denmark, 2800 Kongens Lyngby, Denmark; (S.B.-S.)
| | - Mariann Chriél
- Department of Health Technology Center for Diagnostics, Technical University of Denmark, 2800 Kongens Lyngby, Denmark
| | - Mette Sif Hansen
- Department of Health Technology Center for Diagnostics, Technical University of Denmark, 2800 Kongens Lyngby, Denmark
- Department of Veterinary and Animal Sciences, University of Copenhagen, 1870 Frederiksberg C, Denmark
| | - Christina Vedel-Smith
- Department of Research and Collections, Natural History Museum Aarhus, 8000 Aarhus, Denmark; (C.V.-S.)
| | - Charlotte Vikkelsø Hansen
- Department of Research and Collections, Natural History Museum Aarhus, 8000 Aarhus, Denmark; (C.V.-S.)
| | | | | | - Magnus Wahlberg
- Marine Biological Research Center, University of Southern Denmark, 5300 Kerteminde, Denmark
| | | | - Aage Kristian Olsen Alstrup
- Department of Clinical Medicine, Aarhus University, 8200 Aarhus, Denmark
- Department for Nuclear Medicine & PET, Aarhus University Hospital, 8200 Aarhus, Denmark
| | | | - Cino Pertoldi
- Department of Chemistry and Bioscience—Section of Biology and Environmental Science, Aalborg University, 9220 Aalborg, Denmark
| | - Sussie Pagh
- Department of Chemistry and Bioscience—Section of Biology and Environmental Science, Aalborg University, 9220 Aalborg, Denmark
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8
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Abstract
Journal of Experimental Biology has a long history of reporting research discoveries on animal echolocation, the subject of this Centenary Review. Echolocating animals emit intense sound pulses and process echoes to localize objects in dynamic soundscapes. More than 1100 species of bats and 70 species of toothed whales rely on echolocation to operate in aerial and aquatic environments, respectively. The need to mitigate acoustic clutter and ambient noise is common to both aerial and aquatic echolocating animals, resulting in convergence of many echolocation features, such as directional sound emission and hearing, and decreased pulse intervals and sound intensity during target approach. The physics of sound transmission in air and underwater constrains the production, detection and localization of sonar signals, resulting in differences in response times to initiate prey interception by aerial and aquatic echolocating animals. Anti-predator behavioral responses of prey pursued by echolocating animals affect behavioral foraging strategies in air and underwater. For example, many insect prey can detect and react to bat echolocation sounds, whereas most fish and squid are unresponsive to toothed whale signals, but can instead sense water movements generated by an approaching predator. These differences have implications for how bats and toothed whales hunt using echolocation. Here, we consider the behaviors used by echolocating mammals to (1) track and intercept moving prey equipped with predator detectors, (2) interrogate dynamic sonar scenes and (3) exploit visual and passive acoustic stimuli. Similarities and differences in animal sonar behaviors underwater and in air point to open research questions that are ripe for exploration.
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Affiliation(s)
- Cynthia F. Moss
- Johns Hopkins University, Departments of Psychological and Brain Sciences, Neuroscience and Mechanical Engineering, 3400 N. Charles St., Baltimore, MD 21218, USA
- Kavli Neuroscience Discovery Institute, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Sara Torres Ortiz
- Marine Biological Research Center, University of Southern Denmark, Hindsholmvej 11, 5300 Kerteminde, Denmark
| | - Magnus Wahlberg
- Marine Biological Research Center, University of Southern Denmark, Hindsholmvej 11, 5300 Kerteminde, Denmark
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9
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Bakkeren C, Ladegaard M, Hansen KA, Wahlberg M, Madsen PT, Rojano-Doñate L. Visual deprivation induces a stronger dive response in a harbor porpoise. iScience 2023; 26:106204. [PMID: 36876128 PMCID: PMC9982314 DOI: 10.1016/j.isci.2023.106204] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2022] [Revised: 11/15/2022] [Accepted: 02/10/2023] [Indexed: 02/16/2023] Open
Abstract
The dive response allows marine mammals to perform prolonged breath-hold dives to access rich marine prey resources. Via dynamic adjustments of peripheral vasoconstriction and bradycardia, oxygen consumption can be tailored to breath-hold duration, depth, exercise, and even expectations during dives. By investigating the heart rate of a trained harbor porpoise during a two-alternative forced choice task, where the animal is either acoustically masked or blindfolded, we test the hypothesis that sensory deprivation will lead to a stronger dive response to conserve oxygen when facing a more uncertain and smaller sensory umwelt. We show that the porpoise halves its diving heart rate (from 55 to 25 bpm) when blindfolded but presents no change in heart rate during masking of its echolocation. Therefore, visual stimuli may matter more to echolocating toothed whales than previously assumed, and sensory deprivation can be a major driver of the dive response, possibly as an anti-predator measure.
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Affiliation(s)
- Ciska Bakkeren
- Zoophysiology, Department of Biology, Aarhus University, Building 1131, C. F. Møllers Allé 3, DK-8000 Aarhus C, Denmark
| | - Michael Ladegaard
- Zoophysiology, Department of Biology, Aarhus University, Building 1131, C. F. Møllers Allé 3, DK-8000 Aarhus C, Denmark
| | - Kirstin Anderson Hansen
- Department of Biology, University of Southern Denmark, Campusvej 55, 5230 Odense M, Denmark.,Fjord&Bælt, Margrethes Plads 1, 5300 Kerteminde, Denmark
| | - Magnus Wahlberg
- Department of Biology, University of Southern Denmark, Campusvej 55, 5230 Odense M, Denmark
| | - Peter Teglberg Madsen
- Zoophysiology, Department of Biology, Aarhus University, Building 1131, C. F. Møllers Allé 3, DK-8000 Aarhus C, Denmark
| | - Laia Rojano-Doñate
- Zoophysiology, Department of Biology, Aarhus University, Building 1131, C. F. Møllers Allé 3, DK-8000 Aarhus C, Denmark
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10
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Stepien EN, Olsen MT, Nabe–Nielsen J, Hansen KA, Kristensen JH, Blanchet M, Brando S, Desportes G, Lockyer C, Marcenaro L, Bunskoek P, Kemper J, Siebert U, Wahlberg M. Determination of growth, mass, and body mass index of harbour porpoises (Phocoena phocoena): Implications for conservational status assessment of populations. Glob Ecol Conserv 2023. [DOI: 10.1016/j.gecco.2023.e02384] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
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11
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Bergler C, Smeele SQ, Tyndel SA, Barnhill A, Ortiz ST, Kalan AK, Cheng RX, Brinkløv S, Osiecka AN, Tougaard J, Jakobsen F, Wahlberg M, Nöth E, Maier A, Klump BC. ANIMAL-SPOT enables animal-independent signal detection and classification using deep learning. Sci Rep 2022; 12:21966. [PMID: 36535999 PMCID: PMC9763499 DOI: 10.1038/s41598-022-26429-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2022] [Accepted: 12/14/2022] [Indexed: 12/23/2022] Open
Abstract
Bioacoustic research spans a wide range of biological questions and applications, relying on identification of target species or smaller acoustic units, such as distinct call types. However, manually identifying the signal of interest is time-intensive, error-prone, and becomes unfeasible with large data volumes. Therefore, machine-driven algorithms are increasingly applied to various bioacoustic signal identification challenges. Nevertheless, biologists still have major difficulties trying to transfer existing animal- and/or scenario-related machine learning approaches to their specific animal datasets and scientific questions. This study presents an animal-independent, open-source deep learning framework, along with a detailed user guide. Three signal identification tasks, commonly encountered in bioacoustics research, were investigated: (1) target signal vs. background noise detection, (2) species classification, and (3) call type categorization. ANIMAL-SPOT successfully segmented human-annotated target signals in data volumes representing 10 distinct animal species and 1 additional genus, resulting in a mean test accuracy of 97.9%, together with an average area under the ROC curve (AUC) of 95.9%, when predicting on unseen recordings. Moreover, an average segmentation accuracy and F1-score of 95.4% was achieved on the publicly available BirdVox-Full-Night data corpus. In addition, multi-class species and call type classification resulted in 96.6% and 92.7% accuracy on unseen test data, as well as 95.2% and 88.4% regarding previous animal-specific machine-based detection excerpts. Furthermore, an Unweighted Average Recall (UAR) of 89.3% outperformed the multi-species classification baseline system of the ComParE 2021 Primate Sub-Challenge. Besides animal independence, ANIMAL-SPOT does not rely on expert knowledge or special computing resources, thereby making deep-learning-based bioacoustic signal identification accessible to a broad audience.
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Affiliation(s)
- Christian Bergler
- grid.5330.50000 0001 2107 3311Pattern Recognition Lab, Department of Computer Science, Friedrich-Alexander-Universität Erlangen-Nürnberg, 91058 Erlangen, Germany
| | - Simeon Q. Smeele
- grid.507516.00000 0004 7661 536XCognitive and Cultural Ecology Lab, Max Planck Institute of Animal Behavior, 78315 Radolfzell, Germany ,grid.419518.00000 0001 2159 1813Department of Human Behavior, Ecology and Culture, Max Planck Institute for Evolutionary Anthropology, 04103 Leipzig, Germany ,grid.9811.10000 0001 0658 7699Biology Department, University of Konstanz, 78464 Constance, Germany
| | - Stephen A. Tyndel
- grid.507516.00000 0004 7661 536XCognitive and Cultural Ecology Lab, Max Planck Institute of Animal Behavior, 78315 Radolfzell, Germany ,grid.35403.310000 0004 1936 9991Department of Natural Resources and Environmental Sciences, University of Illinois Urbana-Champaign, Champaign, IL United States
| | - Alexander Barnhill
- grid.5330.50000 0001 2107 3311Pattern Recognition Lab, Department of Computer Science, Friedrich-Alexander-Universität Erlangen-Nürnberg, 91058 Erlangen, Germany
| | - Sara T. Ortiz
- grid.4372.20000 0001 2105 1091Max Planck Institute for Biological Intelligence, in Foundation, Seewiesen Eberhard-Gwinner-Strasse, 82319 Starnberg, Germany
| | - Ammie K. Kalan
- grid.143640.40000 0004 1936 9465Department of Anthropology, University of Victoria, Victoria, BC V8P 5C2 Canada
| | - Rachael Xi Cheng
- grid.418779.40000 0001 0708 0355Leibniz Institute for Zoo and Wildlife Research, Alfred-Kowalke-Straße 17, 10315 Berlin, Germany
| | - Signe Brinkløv
- grid.7048.b0000 0001 1956 2722Department of Bioscience, Wildlife Ecology, Aarhus University, 8410 Rønde, Denmark
| | - Anna N. Osiecka
- grid.8585.00000 0001 2370 4076Department of Vertebrate Ecology and Zoology, Faculty of Biology, University of Gdańsk, 80-308 Gdańsk, Poland
| | - Jakob Tougaard
- grid.7048.b0000 0001 1956 2722Department of Bioscience, Marine Mammal Research, Aarhus University, 4000 Roskilde, Denmark
| | - Freja Jakobsen
- grid.10825.3e0000 0001 0728 0170Department of Biology, University of Southern Denmark, 5230 Odense, Denmark
| | - Magnus Wahlberg
- grid.10825.3e0000 0001 0728 0170Department of Biology, University of Southern Denmark, 5230 Odense, Denmark
| | - Elmar Nöth
- grid.5330.50000 0001 2107 3311Pattern Recognition Lab, Department of Computer Science, Friedrich-Alexander-Universität Erlangen-Nürnberg, 91058 Erlangen, Germany
| | - Andreas Maier
- grid.5330.50000 0001 2107 3311Pattern Recognition Lab, Department of Computer Science, Friedrich-Alexander-Universität Erlangen-Nürnberg, 91058 Erlangen, Germany
| | - Barbara C. Klump
- grid.507516.00000 0004 7661 536XCognitive and Cultural Ecology Lab, Max Planck Institute of Animal Behavior, 78315 Radolfzell, Germany
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12
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Rasmussen MS, Sørensen K, Vittrup MF, Wahlberg M. Pavlovian conditioning of gentoo penguins (Pygoscelis papua) to underwater sound. Biol Open 2022; 11:277210. [PMID: 36226824 DOI: 10.1242/bio.059425] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Accepted: 09/29/2022] [Indexed: 11/20/2022] Open
Abstract
Penguins are known to react to underwater noise, but it is unknown if they make use of sound cues while diving. We tested if captive gentoo penguins (Pygoscelis papua) can pair underwater sounds with food through Pavlovian conditioning. Two seconds after an underwater sound (a 1-4kHz sweep with a received level of 130 dB re 1 µPa rms) was played back to 1-2 unidentifiable penguins, a dead fish was flushed into the water close to the underwater sound source. After eight weeks of conditioning, one or more individual penguins approached the sound source after sound emission in 78.3% out of 230 trials. In 43 intermixed control trials with no sound preceding the fish, the penguins did not show any reaction in the pre-flush period. In an additional experiment, three identified penguins reacted to the sound in 66.7-100% out of 30 trials, with 0% reactions in 5 intermixed control trials. Our experiments demonstrate that gentoo penguins can be conditioned to underwater sound, and that they associate underwater sounds with food. It is possible that gentoos, as well as other species of penguins, use sound cues while foraging. This may explain why penguins have been observed to react negatively to anthropogenic noise.
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Affiliation(s)
- Maria S Rasmussen
- Department of Biology, University of Southern Denmark, Campusvej 55, 5230 Odense M, Denmark
| | - Kenneth Sørensen
- Department of Biology, University of Southern Denmark, Campusvej 55, 5230 Odense M, Denmark.,Institute for Biosciences, University of Rostock, Albert-Einstein-Str. 3, 18059 Rostock, Germany
| | - Malou F Vittrup
- Department of Biology, University of Southern Denmark, Campusvej 55, 5230 Odense M, Denmark
| | - Magnus Wahlberg
- Department of Biology, University of Southern Denmark, Campusvej 55, 5230 Odense M, Denmark
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13
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Brennecke D, Wahlberg M, Gilles A, Siebert U. Age and lunar cycle predict harbor porpoise bycatch in the south-western Baltic Sea. PeerJ 2021; 9:e12284. [PMID: 34760359 PMCID: PMC8556710 DOI: 10.7717/peerj.12284] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2021] [Accepted: 09/20/2021] [Indexed: 11/27/2022] Open
Abstract
The harbor porpoise, Phocoena phocoena, is the only cetacean regularly occurring in the Baltic Sea. During the last decades, several anthropogenic activities have affected porpoises in the Baltic region. Most notably is bycatch in static fishing gear, such as gill nets, which is the main human-induced cause of death in odontocetes. There is still considerable uncertainty about which factors influence the amount of bycatch. In the present study, we reviewed bycatch data collected from 1987 to 2016 from the south-western Baltic Sea. There was a significant difference in bycatch due to seasonality and region, and there was a higher bycatch rate in juveniles than in adults. The only abiotic factor associated with bycatch was the lunar cycle, with more animals bycaught during a full moon. These results improve our understanding of which biotic and abiotic factors are associated with bycatch of Baltic harbor porpoises, which can be used to strengthen conservation endeavors such as managing fishing efforts.
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Affiliation(s)
- Dennis Brennecke
- Institute for Terrestrial and Aquatic Wildlife Research, University of Veterinary Medicine Hannover, Foundation, Büsum, Schleswig-Holstein, Germany.,University of Southern Denmark, Department of Biology, Marine Biological Research Centre, Kerteminde, Denmark.,Leibniz Institute for Science and Mathematics Education, Kiel, Schleswig-Holstein, Germany
| | - Magnus Wahlberg
- University of Southern Denmark, Department of Biology, Marine Biological Research Centre, Kerteminde, Denmark
| | - Anita Gilles
- Institute for Terrestrial and Aquatic Wildlife Research, University of Veterinary Medicine Hannover, Foundation, Büsum, Schleswig-Holstein, Germany
| | - Ursula Siebert
- Institute for Terrestrial and Aquatic Wildlife Research, University of Veterinary Medicine Hannover, Foundation, Büsum, Schleswig-Holstein, Germany
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14
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Smith AB, Madsen PT, Johnson M, Tyack P, Wahlberg M. Toothed whale auditory brainstem responses measured with a non-invasive, on-animal tag. JASA Express Lett 2021; 1:091201. [PMID: 36154211 DOI: 10.1121/10.0006454] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Empirical measurements of odontocete hearing are limited to captive individuals, constituting a fraction of species across the suborder. Data from more species could be available if such measurements were collected from unrestrained animals in the wild. This study investigated whether electrophysiological hearing data could be recorded from a trained harbor porpoise (Phocoena phocoena) using a non-invasive, animal-attached tag. The results demonstrate that auditory brainstem responses to external and self-generated stimuli can be measured from a stationary odontocete using an animal-attached recorder. With additional development, tag-based electrophysiological platforms may facilitate the collection of hearing data from freely swimming odontocetes in the wild.
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Affiliation(s)
- Adam B Smith
- Marine Research Centre, University of Southern Denmark, 5300 Kerteminde, Denmark
| | - Peter T Madsen
- Zoophysiology, Department of Biology, Aarhus University, 8000 Aarhus C, Denmark
| | - Mark Johnson
- Aarhus Institute of Advanced Studies, Aarhus University, 8000 Aarhus C, Denmark
| | - Peter Tyack
- Scottish Oceans Institute, School of Biology, University of St Andrews, KY16 8LB St. Andrews, United Kingdom , , , ,
| | - Magnus Wahlberg
- Marine Research Centre, University of Southern Denmark, 5300 Kerteminde, Denmark
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15
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Abstract
Cooperative hunting involves individual predators relating in time and space to each other’s actions to more efficiently track down and catch prey. The evolution of advanced cognitive abilities and sociality in animals are strongly associated with cooperative hunting abilities as has been shown in lions, chimpanzees, and dolphins. Much less is known about cooperative hunting in seemingly unsocial animals, such as the harbour porpoise (Phocoena phocoena (Linnaeus, 1758)). Using drones, we were able to record 159 hunting sequences of porpoises, out of which 95 sequences involved more than one porpoise. To better understand if the harbour porpoises were individually attracted by the fish school or formed an organized hunting strategy, the behaviour of each individual porpoise in relation to the targeted fish school was analysed. The results indicate role specialization, which is considered the most sophisticated form of collaborative hunting and only rarely seen in animals. Our study challenges previous knowledge about harbour porpoises and opens up for the possibility of other seemingly non-social species employing sophisticated collaborative hunting methods.
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Affiliation(s)
- Sara Torres Ortiz
- Department of Biology, University of Southern Denmark, Campusvej 55, 5230 Odense, Denmark
- Max Planck Institute for Ornithology, Eberhard-Gwinner-Strasse, 82319 Seewiesen, Germany
| | - Johanna Stedt
- Department of Biology, Lund University, SE-223 62 Lund, Sweden
| | - Henrik Skov Midtiby
- Maersk Mc-Kinney Moller Institute, University of Southern Denmark, Campusvej 55, 5230 Odense, Denmark
| | - Henrik Dyrberg Egemose
- Maersk Mc-Kinney Moller Institute, University of Southern Denmark, Campusvej 55, 5230 Odense, Denmark
| | - Magnus Wahlberg
- Department of Biology, University of Southern Denmark, Campusvej 55, 5230 Odense, Denmark
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16
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Martin MJ, Torres Ortiz S, Reyes Reyes MV, Marino A, Iñíguez Bessega M, Wahlberg M. Commerson’s dolphins (Cephalorhynchus commersonii) can relax acoustic crypsis. Behav Ecol Sociobiol 2021. [DOI: 10.1007/s00265-021-03035-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
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17
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Rößler H, Tougaard J, Sabinsky PF, Rasmussen MH, Granquist SM, Wahlberg M. Are Icelandic harbor seals acoustically cryptic to avoid predation? JASA Express Lett 2021; 1:031201. [PMID: 36154560 DOI: 10.1121/10.0003782] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Male harbor seals (Phoca vitulina) produce stereotypic underwater roars during the mating season. It remains unclear to what extent roar structures vary due to predation levels. Here, seal roars from waters with many (Iceland) and few (Denmark and Sweden) predators were compared. Most Icelandic roars included a long pulse train and a pause. Icelandic roars occurred less frequently, lasted longer (20.3 ± 6.5 s), and were recorded with lower received sound levels (98.3 ± 8.9 dB re 1 μPa root mean square) than roars from Denmark and Sweden. Local extrinsic factors may shape sound production in harbor seals more than previously reported.
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Affiliation(s)
- Helen Rößler
- Department of Biology, University of Southern Denmark, Campusvej 55, 5230 Odense M, Denmark
| | - Jakob Tougaard
- Department for Bioscience, Aarhus University, Frederiksborgvej 399, 4000 Roskilde, Denmark
| | - Puk F Sabinsky
- Department of Biology, University of Southern Denmark, Campusvej 55, 5230 Odense M, Denmark
| | - Marianne H Rasmussen
- University of Iceland Research Center in Húsavík, Hafnarstétt 3, 640 Húsavík, Iceland
| | - Sandra M Granquist
- Marine and Freshwater Research Institute, Fornubúðum 5, 220 Hafnarfjörður, Iceland , , , , ,
| | - Magnus Wahlberg
- Department of Biology, University of Southern Denmark, Campusvej 55, 5230 Odense M, Denmark
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18
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Abstract
Wild harbour porpoises (Phocoena phocoena) mainly forage during the night and, because they rely on echolocation to detect their prey, this is also when they are most acoustically active. It has been hypothesised that this activity pattern is a response to the diel behaviour of their major prey species. To test this hypothesis, we monitored the acoustic activity of two captive harbour porpoises held in a net pen continuously during a full year and fed by their human keepers during daylight hours, thus removing the influence of prey activity. The porpoises were exposed to similar temperature and ambient light conditions as free-ranging animals living in the same region. Throughout the year, there was a pronounced diel pattern in acoustic activity of the porpoises, with significantly greater activity at night, and a clear peak around sunrise and sunset throughout the year. Clicking activity was not dependent on lunar illumination or water level. Because the porpoises in the pen are fed and trained during daylight hours, the results indicate that factors other than fish behaviour are strongly influencing the diel clicking behaviour pattern of the species.
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Affiliation(s)
- Anna N Osiecka
- Marine Biological Research Centre, Department of Biology, University of Southern Denmark, Hindsholmvej 11, 5300, Kerteminde, Denmark.
- Department of Biology, University of Southern Denmark, Campusvej 55, 5230, Odense, Denmark.
| | - Owen Jones
- Department of Biology, University of Southern Denmark, Campusvej 55, 5230, Odense, Denmark
- Interdisciplinary Centre on Population Dynamics (CPOP), University of Southern Denmark, Campusvej 55, 5230, Odense, Denmark
| | - Magnus Wahlberg
- Marine Biological Research Centre, Department of Biology, University of Southern Denmark, Hindsholmvej 11, 5300, Kerteminde, Denmark
- Department of Biology, University of Southern Denmark, Campusvej 55, 5230, Odense, Denmark
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19
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Brauckhoff M, Wahlberg M, Haga JÅR, Karlsen HE, Wilson M. Embracing Their Prey at That Dark Hour: Common Cuttlefish (Sepia officinalis) Can Hunt in Nighttime Light Conditions. Front Physiol 2020; 11:525. [PMID: 32587521 PMCID: PMC7298144 DOI: 10.3389/fphys.2020.00525] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2019] [Accepted: 04/29/2020] [Indexed: 11/13/2022] Open
Abstract
Cuttlefish are highly efficient predators, which strongly rely on their anterior binocular visual field for hunting and prey capture. Their complex eyes possess adaptations for low light conditions. Recently, it was discovered that they display camouflaging behavior at night, perhaps to avoid detection by predators, or to increase their nighttime hunting success. This raises the question whether cuttlefish are capable of foraging during nighttime. In the present study, prey capture of the common cuttlefish (Sepia officinalis) was filmed with a high-speed video camera in different light conditions. Experiments were performed in daylight and with near-infrared light sources in two simulated nightlight conditions, as well as in darkness. The body of the common cuttlefish maintained a velocity of less than 0.1 m/s during prey capture, while the tentacles during the seizing phase reached velocities of up to 2.5 m/s and accelerations reached more than 450 m/s2 for single individuals. There was no significant difference between the day and nighttime trials, respectively. In complete darkness, the common cuttlefish was unable to catch any prey. Our results show that the common cuttlefish are capable of catching prey during day- and nighttime light conditions. The common cuttlefish employ similar sensory motor systems and prey capturing techniques during both day- and nighttime conditions.
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Affiliation(s)
- Melanie Brauckhoff
- Department of Biology, University of Southern Denmark, Odense, Denmark
- The Fisheries and Maritime Museum, Esbjerg, Denmark
| | - Magnus Wahlberg
- Department of Biology, University of Southern Denmark, Odense, Denmark
| | - Jens Ådne Rekkedal Haga
- Department of Biosciences, Faculty of Mathematics and Natural Sciences, University of Oslo, Oslo, Norway
| | - Hans Erik Karlsen
- Department of Biosciences, Faculty of Mathematics and Natural Sciences, University of Oslo, Oslo, Norway
| | - Maria Wilson
- Department of Biology, University of Southern Denmark, Odense, Denmark
- Department of Biosciences, Faculty of Mathematics and Natural Sciences, University of Oslo, Oslo, Norway
- NIRAS A/S, Aarhus, Denmark
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20
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Anderson Hansen K, Hernandez A, Mooney TA, Rasmussen MH, Sørensen K, Wahlberg M. The common murre (Uria aalge), an auk seabird, reacts to underwater sound. J Acoust Soc Am 2020; 147:4069. [PMID: 32611143 DOI: 10.1121/10.0001400] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/06/2019] [Accepted: 05/26/2020] [Indexed: 06/11/2023]
Abstract
Marine mammals have fine-tuned hearing abilities, which makes them vulnerable to human-induced sounds from shipping, sonars, pile drivers, and air guns. Many species of marine birds, such as penguins, auks, and cormorants, find their food underwater where light is often limited, suggesting sound detection may play a vital role. Yet, for most marine birds, it is unknown whether they are using, and can thereby be affected by, underwater sound. The authors conducted a series of playback experiments to test whether Alcid seabirds responded to and were disrupted by, underwater sound. Underwater broadband sound bursts and mid-frequency naval 53 C sonar signals were presented to two common murres (Uria aalge) in a quiet pool. The received sound pressure levels varied from 110 to 137 dB re 1 μPa. Both murres showed consistent reactions to sounds of all intensities, as compared to no reactions during control trials. For one of the birds, there was a clearly graded response, so that more responses were found at higher received levels. The authors' findings indicate that common murres may be affected by, and therefore potentially also vulnerable to, underwater noise. The effect of man-made noise on murres, and possibly other marine birds, requires more thorough consideration.
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Affiliation(s)
| | - Ariana Hernandez
- Department of Biology, University of Southern Denmark, Campusvej 55, 5230 Odense M, Denmark
| | - T Aran Mooney
- Woods Hole Oceanographic Institution, 266 Woods Hole Road, Woods Hole, Massachusetts 02543, USA
| | - Marianne H Rasmussen
- The University of Iceland's Research Center in Húsavík, Hafnarstétt 3, 640 Húsavík, Iceland
| | - Kenneth Sørensen
- Department of Biology, University of Southern Denmark, Campusvej 55, 5230 Odense M, Denmark
| | - Magnus Wahlberg
- Department of Biology, University of Southern Denmark, Campusvej 55, 5230 Odense M, Denmark
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21
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Larsen ON, Wahlberg M, Christensen-Dalsgaard J. Amphibious hearing in a diving bird, the great cormorant ( Phalacrocorax carbo sinensis). J Exp Biol 2020; 223:jeb217265. [PMID: 32098879 DOI: 10.1242/jeb.217265] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2019] [Accepted: 02/10/2020] [Indexed: 11/20/2022]
Abstract
Diving birds can spend several minutes underwater during pursuit-dive foraging. To find and capture prey, such as fish and squid, they probably need several senses in addition to vision. Cormorants, very efficient predators of fish, have unexpectedly low visual acuity underwater. So, underwater hearing may be an important sense, as for other diving animals. We measured auditory thresholds and eardrum vibrations in air and underwater of the great cormorant (Phalacrocorax carbo sinensis). Wild-caught cormorant fledglings were anaesthetized, and their auditory brainstem response (ABR) and eardrum vibrations to clicks and tone bursts were measured, first in an anechoic box in air and then in a large water-filled tank, with their head and ears submerged 10 cm below the surface. Both the ABR waveshape and latency, as well as the ABR threshold, measured in units of sound pressure, were similar in air and water. The best average sound pressure sensitivity was found at 1 kHz, both in air (53 dB re. 20 µPa) and underwater (58 dB re. 20 µPa). When thresholds were compared in units of intensity, however, the sensitivity underwater was higher than in air. Eardrum vibration amplitude in both media reflected the ABR threshold curves. These results suggest that cormorants have in-air hearing abilities comparable to those of similar-sized diving birds, and that their underwater hearing sensitivity is at least as good as their aerial sensitivity. This, together with the morphology of the outer ear (collapsible meatus) and middle ear (thickened eardrum), suggests that cormorants may have anatomical and physiological adaptations for amphibious hearing.
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Affiliation(s)
- Ole Næsbye Larsen
- Sound and Behaviour Group, Department of Biology, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark
| | - Magnus Wahlberg
- Sound and Behaviour Group, Department of Biology, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark
| | - Jakob Christensen-Dalsgaard
- Sound and Behaviour Group, Department of Biology, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark
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22
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Sørensen K, Neumann C, Dähne M, Hansen KA, Wahlberg M. Gentoo penguins ( Pygoscelis papua) react to underwater sounds. R Soc Open Sci 2020; 7:191988. [PMID: 32257350 PMCID: PMC7062047 DOI: 10.1098/rsos.191988] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/13/2019] [Accepted: 01/31/2020] [Indexed: 06/11/2023]
Abstract
Marine mammals and diving birds face several physiological challenges under water, affecting their thermoregulation and locomotion as well as their sensory systems. Therefore, marine mammals have modified ears for improved underwater hearing. Underwater hearing in birds has been studied in a few species, but for the record-holding divers, such as penguins, there are no detailed data. We played underwater noise bursts to gentoo penguins (Pygoscelis papua) in a large tank at received sound pressure levels between 100 and 120 dB re 1 µPa RMS. The penguins showed a graded reaction to the noise bursts, ranging from no reactions at 100 dB to strong reactions in more than 60% of the playbacks at 120 dB re 1 µPa. The responses were always directed away from the sound source. The fact that penguins can detect and react to underwater stimuli may indicate that they make use of sound stimuli for orientation and prey detection during dives. Further, it suggests that penguins may be sensitive to anthropogenic noise, like many species of marine mammals.
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Affiliation(s)
- K. Sørensen
- Department of Biology, University of Southern Denmark, Campusvej 55, 5230 Odense M, Denmark
| | - C. Neumann
- Department of Biology, University of Southern Denmark, Campusvej 55, 5230 Odense M, Denmark
| | - M. Dähne
- German Oceanographic Museum Foundation, Katharinenberg 14-20, 18439 Stralsund, Germany
| | - K. A. Hansen
- Department of Biology, University of Southern Denmark, Campusvej 55, 5230 Odense M, Denmark
| | - M. Wahlberg
- Department of Biology, University of Southern Denmark, Campusvej 55, 5230 Odense M, Denmark
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Mustonen M, Klauson A, Andersson M, Clorennec D, Folegot T, Koza R, Pajala J, Persson L, Tegowski J, Tougaard J, Wahlberg M, Sigray P. Spatial and Temporal Variability of Ambient Underwater Sound in the Baltic Sea. Sci Rep 2019; 9:13237. [PMID: 31519926 PMCID: PMC6744399 DOI: 10.1038/s41598-019-48891-x] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2018] [Accepted: 07/05/2019] [Indexed: 11/09/2022] Open
Abstract
During last decades, anthropogenic underwater sound and its chronic impact on marine species have been recognised as an environmental protection challenge. At the same time, studies on the spatial and temporal variability of ambient sound, and how it is affected by biotic, abiotic and anthropogenic factors are lacking. This paper presents analysis of a large-scale and long-term underwater sound monitoring in the Baltic Sea. Throughout the year 2014, sound was monitored in 36 Baltic Sea locations. Selected locations covered different natural conditions and ship traffic intensities. The 63 Hz, 125 Hz and 2 kHz one-third octave band sound pressure levels were calculated and analysed. The levels varied significantly from one monitoring location to another. The annual median sound pressure level of the quietest and the loudest location differed almost 50 dB in the 63 Hz one-third octave band. Largest difference in the monthly medians was 15 dB in 63 Hz one-third octave band. The same monitoring locations annual estimated probability density functions for two yearly periods show strong similarity. The data variability grows as the averaging time period is reduced. Maritime traffic elevates the ambient sound levels in many areas of the Baltic Sea during extensive time periods.
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Affiliation(s)
- Mirko Mustonen
- Tallinn University of Technology, School of Engineering, Tallinn, 19086, Estonia.
| | - Aleksander Klauson
- Tallinn University of Technology, School of Engineering, Tallinn, 19086, Estonia
| | | | | | | | - Radomił Koza
- University of Gdansk, Institute of Oceanography, Gdynia, 81-378, Poland
| | - Jukka Pajala
- Finnish Environment Institute, Helsinki, FI-00251, Finland
| | - Leif Persson
- Swedish Defence Research Agency, Stockholm, SE-164 90, Sweden
| | - Jarosław Tegowski
- University of Gdansk, Institute of Oceanography, Gdynia, 81-378, Poland
| | - Jakob Tougaard
- Aarhus University, Department of Bioscience, Roskilde, 4000, Denmark
| | - Magnus Wahlberg
- University of Southern Denmark, Department of Biology, Odense M, 5230, Denmark
| | - Peter Sigray
- Swedish Defence Research Agency, Stockholm, SE-164 90, Sweden
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Smeele SQ, Anderson Hansen K, Ortiz ST, Johansson F, Kristensen JH, Larsson J, Siebert U, Wahlberg M. Memory for own behaviour in pinnipeds. Anim Cogn 2019; 22:947-958. [PMID: 31240504 DOI: 10.1007/s10071-019-01286-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2018] [Revised: 06/09/2019] [Accepted: 06/18/2019] [Indexed: 11/27/2022]
Abstract
Pinnipeds are aquatic predators feeding on a vast range of prey, and their social behaviour differs greatly between species (from extreme polygyny in some sea lions to monogamy in some true seals). It has been hypothesised that the foraging and social complexity of their lifestyle should drive the evolution of their cognitive abilities. To investigate how aware pinnipeds are of their own behaviour, a grey seal (Halichoerus grypus), two harbour seals (Phoca vitulina) and four South American sea lions (Otaria flavescens) were trained to repeat their own behaviour on command. Three already trained behaviours were used, and the animal was asked to repeat the behaviour twice to ensure that the animal recalled its own behaviour and not the command given for the previous behaviour. All three species could recall their own behaviour significantly better than by chance. The duration for which the animals could recall their behaviour was tested using a staircase paradigm. A delay was implemented between the completion of the behaviour and the command to repeat it. The delay was increased after correct responses and decreased after incorrect responses. The performance of all species fell towards chance level after 12-18 s, with no significant difference between species. These results indicate that sea lions and true seals are aware of their own behaviour and that true seals have similar short-term memory abilities. It also shows that pinnipeds have less developed short-term memory abilities compared to other aquatic predators, such as the bottlenose dolphin. The complexity of pinniped foraging and social behaviour does not seem to have driven the evolution of short-term memory abilities in these animals but might have contributed to their ability to recall their own behaviour.
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Affiliation(s)
- Simeon Quirinus Smeele
- Department of Biology, University of Southern Denmark, Campusvej 55, 5230, Odense, Denmark.
| | - Kirstin Anderson Hansen
- Department of Biology, University of Southern Denmark, Campusvej 55, 5230, Odense, Denmark
- Institute for Terrestrial and Aquatic Wildlife Research (ITAW), University of Veterinary Medicine Hannover, Foundation, Werftstr. 6, 25761, Büsum, Germany
| | - Sara Torres Ortiz
- Department of Biology, University of Southern Denmark, Campusvej 55, 5230, Odense, Denmark
- Dolphin Adventure, Vallarta Adventures, Las Palmas 39, 63732, Nuevo Vallarta, Nayarit, Mexico
| | | | | | | | - Ursula Siebert
- Institute for Terrestrial and Aquatic Wildlife Research (ITAW), University of Veterinary Medicine Hannover, Foundation, Werftstr. 6, 25761, Büsum, Germany
| | - Magnus Wahlberg
- Department of Biology, University of Southern Denmark, Campusvej 55, 5230, Odense, Denmark
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Mooney TA, Smith A, Larsen ON, Hansen KA, Wahlberg M, Rasmussen MH. Field-based hearing measurements of two seabird species. J Exp Biol 2019; 222:222/4/jeb190710. [DOI: 10.1242/jeb.190710] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2018] [Accepted: 01/03/2019] [Indexed: 11/20/2022]
Abstract
ABSTRACT
Hearing is a primary sensory modality for birds. For seabirds, auditory data is challenging to obtain and hearing data are limited. Here, we present methods to measure seabird hearing in the field, using two Alcid species: the common murre Uria aalge and the Atlantic puffin Fratercula arctica. Tests were conducted in a portable semi-anechoic crate using physiological auditory evoked potential (AEP) methods. The crate and AEP system were easily transportable to northern Iceland field sites, where wild birds were caught, sedated, studied and released. The resulting data demonstrate the feasibility of a field-based application of an established neurophysiology method, acquiring high quality avian hearing data in a relatively quiet setting. Similar field methods could be applied to other seabirds, and other bird species, resulting in reliable hearing data from a large number of individuals with a modest field effort. The results will provide insights into the sound sensitivity of species facing acoustic habitat degradation.
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Affiliation(s)
- T. Aran Mooney
- Biology Department, Woods Hole Oceanographic Institution, 266 Woods Hole Rd, Woods Hole, MA 02543, USA
| | - Adam Smith
- Biology Department, Woods Hole Oceanographic Institution, 266 Woods Hole Rd, Woods Hole, MA 02543, USA
| | - Ole Naesbye Larsen
- Department of Biology, University of Southern Denmark, DK-5230 Odense M, Denmark
| | | | - Magnus Wahlberg
- Department of Biology, University of Southern Denmark, DK-5230 Odense M, Denmark
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Torres Ortiz S, Maxwell A, Krasheninnikova A, Wahlberg M, Larsen ON. Problem solving capabilities of peach-fronted conures (Eupsittula aurea) studied with the string-pulling test. BEHAVIOUR 2019. [DOI: 10.1163/1568539x-00003539] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Abstract
The problem-solving capabilities of four small parrots (peach-fronted conures, Eupsittula aurea) were investigated using string-pulling tests. In seven different tasks, one string was baited following a randomized order. The parrots could retrieve the food reward after a wrong choice as the choice was not forced. Additionally, we applied a non-intuitive pulley task with the strings arranged in front of, instead of below the birds. All four parrots performed very well in the multiple, slanted, and broken string tasks, but all failed in the crossed-string task. Only two parrots solved the single pulley task. All four parrots performed successfully in the multiple pulley task but all failed in the broken pulley condition. Our results suggest that peach-fronted conures solve string-pulling tasks without relying on simple proximity based rules, but that they have evolved cognitive abilities enabling goal-directedness, the understanding of functionality, and a concept of connectedness between two objects.
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Affiliation(s)
- Sara Torres Ortiz
- aDepartment of Biology, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark
| | - Alyssa Maxwell
- aDepartment of Biology, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark
| | - Anastasia Krasheninnikova
- bMax-Planck-Institute for Ornithology, Eberhard-Gwinner-Str., DE-82319 Seewiesen, Germany
- cMax-Planck Comparative Cognition Research Station, ES-Loro Parque Fundación, 38400 Puerto de la Cruz, Tenerife, Spain
| | - Magnus Wahlberg
- aDepartment of Biology, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark
| | - Ole Næsbye Larsen
- aDepartment of Biology, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark
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Rojano-Doñate L, McDonald BI, Wisniewska DM, Johnson M, Teilmann J, Wahlberg M, Højer-Kristensen J, Madsen PT. High field metabolic rates of wild harbour porpoises. J Exp Biol 2018; 221:221/23/jeb185827. [DOI: 10.1242/jeb.185827] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2018] [Accepted: 10/01/2018] [Indexed: 11/20/2022]
Abstract
ABSTRACT
Reliable estimates of field metabolic rates (FMRs) in wild animals are essential for quantifying their ecological roles, as well as for evaluating fitness consequences of anthropogenic disturbances. Yet, standard methods for measuring FMR are difficult to use on free-ranging cetaceans whose FMR may deviate substantially from scaling predictions using terrestrial mammals. Harbour porpoises (Phocoena phocoena) are among the smallest marine mammals, and yet they live in cold, high-latitude waters where their high surface-to-volume ratio suggests high FMRs to stay warm. However, published FMR estimates of harbour porpoises are contradictory, with some studies claiming high FMRs and others concluding that the energetic requirements of porpoises resemble those of similar-sized terrestrial mammals. Here, we address this controversy using data from a combination of captive and wild porpoises to estimate the FMR of wild porpoises. We show that FMRs of harbour porpoises are up to two times greater than for similar-sized terrestrial mammals, supporting the hypothesis that small, carnivorous marine mammals in cold water have elevated FMRs. Despite the potential cost of thermoregulation in colder water, harbour porpoise FMRs are stable over seasonally changing water temperatures. Varying heat loss seems to be managed via cyclical fluctuations in energy intake, which serve to build up a blubber layer that largely offsets the extra costs of thermoregulation during winter. Such high FMRs are consistent with the recently reported high feeding rates of wild porpoises and highlight concerns about the potential impact of human activities on individual fitness and population dynamics.
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Affiliation(s)
- Laia Rojano-Doñate
- Zoophysiology, Department of Bioscience, Aarhus University, 8000 Aarhus, Denmark
| | - Birgitte I. McDonald
- Moss Landing Marine Laboratories, California State University, Moss Landing, CA 95039-9647, USA
| | | | - Mark Johnson
- Sea Mammal Research Unit, University of St Andrews, St Andrews KY16 8LB, UK
| | - Jonas Teilmann
- Marine Mammal Research, Department of Bioscience, Aarhus University, 4000 Roskilde, Denmark
| | - Magnus Wahlberg
- Marine Biological Research Center, Department of Biology, University of Southern Denmark, 5300 Kerteminde, Denmark
- Fjord&Bælt, 5300 Kerteminde, Denmark
| | | | - Peter T. Madsen
- Zoophysiology, Department of Bioscience, Aarhus University, 8000 Aarhus, Denmark
- Aarhus Institute of Advanced Studies, Aarhus University, 8000 Aarhus, Denmark
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Hansen KA, Maxwell A, Siebert U, Larsen ON, Wahlberg M. Great cormorants (Phalacrocorax carbo) can detect auditory cues while diving. Naturwissenschaften 2017; 104:45. [PMID: 28477271 DOI: 10.1007/s00114-017-1467-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2016] [Revised: 04/26/2017] [Accepted: 04/27/2017] [Indexed: 11/27/2022]
Abstract
In-air hearing in birds has been thoroughly investigated. Sound provides birds with auditory information for species and individual recognition from their complex vocalizations, as well as cues while foraging and for avoiding predators. Some 10% of existing species of birds obtain their food under the water surface. Whether some of these birds make use of acoustic cues while underwater is unknown. An interesting species in this respect is the great cormorant (Phalacrocorax carbo), being one of the most effective marine predators and relying on the aquatic environment for food year round. Here, its underwater hearing abilities were investigated using psychophysics, where the bird learned to detect the presence or absence of a tone while submerged. The greatest sensitivity was found at 2 kHz, with an underwater hearing threshold of 71 dB re 1 μPa rms. The great cormorant is better at hearing underwater than expected, and the hearing thresholds are comparable to seals and toothed whales in the frequency band 1-4 kHz. This opens up the possibility of cormorants and other aquatic birds having special adaptations for underwater hearing and making use of underwater acoustic cues from, e.g., conspecifics, their surroundings, as well as prey and predators.
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Affiliation(s)
- Kirstin Anderson Hansen
- Department of Biology, Marine Biological Research Center, University of Southern Denmark, Hindsholmvej 11, 5300, Kerteminde, Denmark.
| | - Alyssa Maxwell
- Department of Biology, Marine Biological Research Center, University of Southern Denmark, Hindsholmvej 11, 5300, Kerteminde, Denmark
| | - Ursula Siebert
- Institute for Terrestrial and Aquatic Wildlife Research (ITAW), University of Veterinary Medicine Hannover, Foundation, Bischofsholer Damm 15, 30173, Hannover, Germany
| | - Ole Næsbye Larsen
- Department of Biology, Marine Biological Research Center, University of Southern Denmark, Hindsholmvej 11, 5300, Kerteminde, Denmark
| | - Magnus Wahlberg
- Department of Biology, Marine Biological Research Center, University of Southern Denmark, Hindsholmvej 11, 5300, Kerteminde, Denmark
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29
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Maxwell A, Hansen KA, Ortiz ST, Larsen ON, Siebert U, Wahlberg M. In-air hearing of the great cormorant ( Phalacrocorax carbo). Biol Open 2017; 6:496-502. [PMID: 28288967 PMCID: PMC5399558 DOI: 10.1242/bio.023879] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2016] [Accepted: 03/09/2017] [Indexed: 11/20/2022] Open
Abstract
Many aquatic birds use sounds extensively for in-air communication. Regardless of this, we know very little about their hearing abilities. The in-air audiogram of a male adult great cormorant (Phalacrocorax carbo) was determined using psychophysical methods (method of constants). Hearing thresholds were derived using pure tones of five different frequencies. The lowest threshold was at 2 kHz: 18 dB re 20 µPa rms. Thresholds derived using signal detection theory were within 2 dB of the ones derived using classical psychophysics. The great cormorant is more sensitive to in-air sounds than previously believed and its hearing abilities are comparable to several other species of birds of similar size. This knowledge is important for our understanding of the hearing abilities of other species of sea birds. It can also be used to develop cormorant deterrent devices for fisheries, as well as to assess the impact of increasing in-air anthropogenic noise levels on cormorants and other aquatic birds.
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Affiliation(s)
- Alyssa Maxwell
- Marine Biological Research Centre, Department of Biology, University of Southern Denmark, Hindsholmvej 11, Kerteminde DK-5300, Denmark
| | - Kirstin Anderson Hansen
- Marine Biological Research Centre, Department of Biology, University of Southern Denmark, Hindsholmvej 11, Kerteminde DK-5300, Denmark
| | - Sara Torres Ortiz
- Marine Biological Research Centre, Department of Biology, University of Southern Denmark, Hindsholmvej 11, Kerteminde DK-5300, Denmark
| | - Ole Næsbye Larsen
- Marine Biological Research Centre, Department of Biology, University of Southern Denmark, Hindsholmvej 11, Kerteminde DK-5300, Denmark
| | - Ursula Siebert
- Institute for Terrestrial and Aquatic Wildlife Research (ITAW), University of Veterinary Medicine Hannover, Foundation, Werftstrasse 6, Büsum D-25761, Germany
| | - Magnus Wahlberg
- Marine Biological Research Centre, Department of Biology, University of Southern Denmark, Hindsholmvej 11, Kerteminde DK-5300, Denmark
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30
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Sabinsky PF, Larsen ON, Wahlberg M, Tougaard J. Temporal and spatial variation in harbor seal (Phoca vitulina L.) roar calls from southern Scandinavia. J Acoust Soc Am 2017; 141:1824. [PMID: 28372059 DOI: 10.1121/1.4977999] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Male harbor seals gather around breeding sites for competitive mating displays. Here, they produce underwater vocalizations possibly to attract females and/or scare off other males. These calls offer prospects for passive acoustic monitoring. Acoustic monitoring requires a good understanding of natural variation in calling behavior both temporally and among geographically separate sites. Such variation in call structure and calling patterns were studied in harbor seal vocalizations recorded at three locations in Danish and Swedish waters. There was a strong seasonality in the calls from end of June to early August. Vocalizations at two locations followed a diel pattern, with an activity peak at night. Recordings from one location also showed a peak in call rate at high tide. Large geographic variations were obvious in the total duration of the so-called roar call, the duration of the most prominent part of the call (the roar burst), and of percentage of energy in roar burst. A similarly large variation was also found when comparing the recordings from two consecutive years at the same site. Thus, great care must be taken to separate variation attributable to recording conditions from genuine biological differences when comparing harbor seal roars among recording sites and between years.
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Affiliation(s)
- Puk Faxe Sabinsky
- Department of Biology, University of Southern Denmark, Campusvej 55, 5230 Odense M, Denmark
| | - Ole Næsbye Larsen
- Department of Biology, University of Southern Denmark, Campusvej 55, 5230 Odense M, Denmark
| | - Magnus Wahlberg
- Department of Biology, University of Southern Denmark, Campusvej 55, 5230 Odense M, Denmark
| | - Jakob Tougaard
- Department for Bioscience, Aarhus University, Frederiksborgvej 399, 4000 Roskilde, Denmark
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Wahlberg M, Delgado-García L, Kristensen JH. Precocious hearing in harbour porpoise neonates. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2017; 203:121-132. [DOI: 10.1007/s00359-017-1145-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2016] [Accepted: 01/04/2017] [Indexed: 11/29/2022]
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Oliveira C, Wahlberg M, Silva MA, Johnson M, Antunes R, Wisniewska DM, Fais A, Gonçalves J, Madsen PT. Sperm whale codas may encode individuality as well as clan identity. J Acoust Soc Am 2016; 139:2860. [PMID: 27250178 DOI: 10.1121/1.4949478] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Sperm whales produce codas for communication that can be grouped into different types according to their temporal patterns. Codas have led researchers to propose that sperm whales belong to distinct cultural clans, but it is presently unclear if they also convey individual information. Coda clicks comprise a series of pulses and the delay between pulses is a function of organ size, and therefore body size, and so is one potential source of individual information. Another potential individual-specific parameter could be the inter-click intervals within codas. To test whether these parameters provide reliable individual cues, stereo-hydrophone acoustic tags (Dtags) were attached to five sperm whales of the Azores, recording a total of 802 codas. A discriminant function analysis was used to distinguish 288 5 Regular codas from four of the sperm whales and 183 3 Regular codas from two sperm whales. The results suggest that codas have consistent individual features in their inter-click intervals and inter-pulse intervals which may contribute to individual identification. Additionally, two whales produced different coda types in distinct foraging dive phases. Codas may therefore be used by sperm whales to convey information of identity as well as activity within a social group to a larger extent than previously assumed.
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Affiliation(s)
- Cláudia Oliveira
- Marine and Environmental Sciences Centre and Institute of Marine Research, Departamento de Oceanografia e Pescas, Universidade dos Açores, 9901-862 Horta, Portugal
| | - Magnus Wahlberg
- Department of Biology, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark
| | - Mónica A Silva
- Marine and Environmental Sciences Centre and Institute of Marine Research, Departamento de Oceanografia e Pescas, Universidade dos Açores, 9901-862 Horta, Portugal
| | - Mark Johnson
- Sea Mammal Research Unit, Scottish Oceans Institute, University of St. Andrews, St. Andrews, Fife KY16 8LB, United Kingdom
| | - Ricardo Antunes
- Ocean Giants Program, Global Conservation Programs, Wildlife Conservation Society, 2300 Southern Boulevard, Bronx, New York 10460, USA
| | - Danuta M Wisniewska
- Zoophysiology, Department of Bioscience, Aarhus University, Ny Munkegade 116, DK-8000 Aarhus C, Denmark
| | - Andrea Fais
- Institute for Terrestrial and Aquatic Wildlife Research, University of Veterinary Medicine, Bischofsholer Damm 15, 30173 Hannover, Germany
| | - João Gonçalves
- Marine and Environmental Sciences Centre and Institute of Marine Research, Departamento de Oceanografia e Pescas, Universidade dos Açores, 9901-862 Horta, Portugal
| | - Peter T Madsen
- Zoophysiology, Department of Bioscience, Aarhus University, Ny Munkegade 116, DK-8000 Aarhus C, Denmark
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Wisniewska DM, Ratcliffe JM, Beedholm K, Christensen CB, Johnson M, Koblitz JC, Wahlberg M, Madsen PT. Range-dependent flexibility in the acoustic field of view of echolocating porpoises (Phocoena phocoena). eLife 2015; 4:e05651. [PMID: 25793440 PMCID: PMC4413254 DOI: 10.7554/elife.05651] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2014] [Accepted: 03/19/2015] [Indexed: 12/03/2022] Open
Abstract
Toothed whales use sonar to detect, locate, and track prey. They adjust emitted sound intensity, auditory sensitivity and click rate to target range, and terminate prey pursuits with high-repetition-rate, low-intensity buzzes. However, their narrow acoustic field of view (FOV) is considered stable throughout target approach, which could facilitate prey escape at close-range. Here, we show that, like some bats, harbour porpoises can broaden their biosonar beam during the terminal phase of attack but, unlike bats, maintain the ability to change beamwidth within this phase. Based on video, MRI, and acoustic-tag recordings, we propose this flexibility is modulated by the melon and implemented to accommodate dynamic spatial relationships with prey and acoustic complexity of surroundings. Despite independent evolution and different means of sound generation and transmission, whales and bats adaptively change their FOV, suggesting that beamwidth flexibility has been an important driver in the evolution of echolocation for prey tracking. DOI:http://dx.doi.org/10.7554/eLife.05651.001 Bats and toothed whales such as porpoises have independently evolved the same solution for hunting prey when it is hard to see. Bats hunt in the dark with little light to allow them to see the insects they chase. Porpoises hunt in murky water where different ocean environments can quickly obscure fish from view. So, both bats and porpoises evolved to emit a beam of sound and then track their prey based on the echoes of that sound bouncing off the prey and other objects. This process is called echolocation. A narrow beam of sound can help a porpoise or bat track distant prey. But as either animal closes in on its prey such a narrow sound beam can be a disadvantage because prey can easily escape to one side. Scientists recently found that bats can widen their sound beam as they close in on prey by changing the frequency—or pitch—of the signal they emit or by adjusting how they open their mouth. Porpoises, by contrast, create their echolocation clicks by forcing air through a structure in their blowhole called the phonic lips. The sound is transmitted through a fatty structure on the front of their head known as the melon, which gives these animals their characteristic round-headed look, before being transmitted into the sea. Porpoises would also likely benefit from widening their echolocation beam as they approach prey, but it was not clear if and how they could do this. Wisniewska et al. used 48 tightly spaced underwater microphones to record the clicks emitted by three captive porpoises as they approached a target or a fish. This revealed that in the last stage of their approach, the porpoises could triple the area their sound beam covered, giving them a ‘wide angle view’ as they closed in. This widening of the sound beam occurred during a very rapid series of echolocation signals called a buzz, which porpoises and bats perform at the end of a pursuit. Unlike bats, porpoises are able to continue to change the width of their sound beam throughout the buzz. Wisniewska et al. also present a video that shows that the shape of the porpoise's melon changes rapidly during a buzz, which may explain the widening beam. Furthermore, images obtained using a technique called magnetic resonance imaging (MRI) revealed that a porpoise has a network of facial muscles that are capable of producing these beam-widening melon distortions. As both bats and porpoises have evolved the capability to adjust the width of their sound beam, this ability is likely to be crucial for hunting effectively using echolocation. DOI:http://dx.doi.org/10.7554/eLife.05651.002
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Affiliation(s)
| | - John M Ratcliffe
- Sound and Behaviour Group, Institute of Biology, University of Southern Denmark, Odense, Denmark
| | - Kristian Beedholm
- Zoophysiology, Department of Bioscience, Aarhus University, Aarhus, Denmark
| | | | - Mark Johnson
- Scottish Oceans Institute, University of St Andrews, St Andrews, Scotland
| | - Jens C Koblitz
- Animal Physiology, Institute for Neurobiology, University of Tübingen, Tübingen, Germany
| | - Magnus Wahlberg
- Sound and Behaviour Group, Institute of Biology, University of Southern Denmark, Odense, Denmark
| | - Peter T Madsen
- Zoophysiology, Department of Bioscience, Aarhus University, Aarhus, Denmark
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35
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Jensen FH, Wahlberg M, Beedholm K, Johnson M, Soto NA, Madsen PT. Single-click beam patterns suggest dynamic changes to the field of view of echolocating Atlantic spotted dolphins (Stenella frontalis) in the wild. J Exp Biol 2015; 218:1314-24. [DOI: 10.1242/jeb.116285] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2014] [Accepted: 02/23/2015] [Indexed: 11/20/2022]
Abstract
Echolocating animals exercise an extensive control over the spectral and temporal properties of their biosonar signals to facilitate perception of their actively generated auditory scene when homing in on prey. The intensity and directionality of the biosonar beam defines the field of view of echolocating animals by affecting the acoustic detection range and angular coverage. However, the spatial relationship between an echolocating predator and its prey changes rapidly, resulting in different biosonar requirements throughout prey pursuit and capture. Here we measured single click beam patterns using a parametric fit procedure to test whether free-ranging Atlantic spotted dolphins (Stenella frontalis) modify their biosonar beamwidth. We recorded echolocation clicks using a linear array of receivers and estimated the beamwidth of individual clicks using a parametric spectral fit, cross-validated with well-established composite beam pattern estimates. The dolphins apparently increased the biosonar beamwidth, to a large degree without changing the signal frequency, when they approached the recording array. This is comparable to bats that also expand their field of view during prey capture, but achieve this by decreasing biosonar frequency. This behaviour may serve to decrease the risk that rapid escape movements of prey take them outside the biosonar beam of the predator. It is likely that shared sensory requirements have resulted in bats and toothed whales expanding their acoustic field of view at close range to increase the likelihood of successfully acquiring prey using echolocation, representing a case of convergent evolution of echolocation behaviour between these two taxa.
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Affiliation(s)
- Frants H. Jensen
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ 08540, USA
- Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA
| | - Magnus Wahlberg
- Fjord&Bælt, Margrethes Plads 1, 5300 Kerteminde, Denmark
- Marine Biological Research Center, University of Southern Denmark, Hindsholmsvej 11, 5300 Kerteminde, Denmark
| | - Kristian Beedholm
- Zoophysiology, Department of Bioscience, Aarhus University, 8000 Aarhus, Denmark
| | - Mark Johnson
- Scottish Oceans Institute, University of St. Andrews, Fife, KY16 8LB, United Kingdom
| | - Natacha Aguilar Soto
- Scottish Oceans Institute, University of St. Andrews, Fife, KY16 8LB, United Kingdom
- BIOECOMAC, Dept. Animal Biology, International Campus of Excellence, La Laguna University, La Laguna 38206, Tenerife, Spain
| | - Peter T. Madsen
- Zoophysiology, Department of Bioscience, Aarhus University, 8000 Aarhus, Denmark
- Murdoch University Cetacean Research Unit, School of Veterinary and Life Sciences, Murdoch University, South Street, Murdoch, Western Australia 6150, Australia
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Wilson M, Wahlberg M, Surlykke A, Madsen PT. Ultrasonic predator-prey interactions in water-convergent evolution with insects and bats in air? Front Physiol 2013; 4:137. [PMID: 23781206 PMCID: PMC3679510 DOI: 10.3389/fphys.2013.00137] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2013] [Accepted: 05/21/2013] [Indexed: 11/18/2022] Open
Abstract
Toothed whales and bats have independently evolved biosonar systems to navigate and locate and catch prey. Such active sensing allows them to operate in darkness, but with the potential cost of warning prey by the emission of intense ultrasonic signals. At least six orders of nocturnal insects have independently evolved ears sensitive to ultrasound and exhibit evasive maneuvers when exposed to bat calls. Among aquatic prey on the other hand, the ability to detect and avoid ultrasound emitting predators seems to be limited to only one subfamily of Clupeidae: the Alosinae (shad and menhaden). These differences are likely rooted in the different physical properties of air and water where cuticular mechanoreceptors have been adapted to serve as ultrasound sensitive ears, whereas ultrasound detection in water have called for sensory cells mechanically connected to highly specialized gas volumes that can oscillate at high frequencies. In addition, there are most likely differences in the risk of predation between insects and fish from echolocating predators. The selection pressure among insects for evolving ultrasound sensitive ears is high, because essentially all nocturnal predation on flying insects stems from echolocating bats. In the interaction between toothed whales and their prey the selection pressure seems weaker, because toothed whales are by no means the only marine predators placing a selection pressure on their prey to evolve specific means to detect and avoid them. Toothed whales can generate extremely intense sound pressure levels, and it has been suggested that they may use these to debilitate prey. Recent experiments, however, show that neither fish with swim bladders, nor squid are debilitated by such signals. This strongly suggests that the production of high amplitude ultrasonic clicks serve the function of improving the detection range of the toothed whale biosonar system rather than debilitation of prey.
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Affiliation(s)
- Maria Wilson
- Department of Bioscience, The Faculty of Mathematics and Natural Sciences, University of OsloOslo, Norway
| | - Magnus Wahlberg
- Institute of Biology, University of Southern DenmarkOdense, Denmark
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Oliveira C, Wahlberg M, Johnson M, Miller PJO, Madsen PT. The function of male sperm whale slow clicks in a high latitude habitat: communication, echolocation, or prey debilitation? J Acoust Soc Am 2013; 133:3135-3144. [PMID: 23654416 DOI: 10.1121/1.4795798] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Sperm whales produce different click types for echolocation and communication. Usual clicks and buzzes appear to be used primarily in foraging while codas are thought to function in social communication. The function of slow clicks is less clear, but they appear to be produced by males at higher latitudes, where they primarily forage solitarily, and on the breeding grounds, where they roam between groups of females. Here the behavioral context in which these vocalizations are produced and the function they may serve was investigated. Ninety-nine hours of acoustic and diving data were analyzed from sound recording tags on six male sperm whales in Northern Norway. The 755 slow clicks detected were produced by tagged animals at the surface (52%), ascending from a dive (37%), and during the bottom phase (11%), but never during the descent. Slow clicks were not associated with the production of buzzes, other echolocation clicks, or fast maneuvering that would indicate foraging. Some slow clicks were emitted in seemingly repetitive temporal patterns supporting the hypothesis that the function for slow clicks on the feeding grounds is long range communication between males, possibly relaying information about individual identity or behavioral states.
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Affiliation(s)
- Cláudia Oliveira
- Departamento de Oceanografia e Pescas e Instituto do Mar- Universidade dos Açores, Horta, Açores, Portugal.
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Wisniewska DM, Johnson M, Beedholm K, Wahlberg M, Madsen PT. Acoustic gaze adjustments during active target selection in echolocating porpoises. ACTA ACUST UNITED AC 2013; 215:4358-73. [PMID: 23175527 DOI: 10.1242/jeb.074013] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Visually dominant animals use gaze adjustments to organize perceptual inputs for cognitive processing. Thereby they manage the massive sensory load from complex and noisy scenes. Echolocation, as an active sensory system, may provide more opportunities to control such information flow by adjusting the properties of the sound source. However, most studies of toothed whale echolocation have involved stationed animals in static auditory scenes for which dynamic information control is unnecessary. To mimic conditions in the wild, we designed an experiment with captive, free-swimming harbor porpoises tasked with discriminating between two hydrophone-equipped targets and closing in on the selected target; this allowed us to gain insight into how porpoises adjust their acoustic gaze in a multi-target dynamic scene. By means of synchronized cameras, an acoustic tag and on-target hydrophone recordings we demonstrate that porpoises employ both beam direction control and range-dependent changes in output levels and pulse intervals to accommodate their changing spatial relationship with objects of immediate interest. We further show that, when switching attention to another target, porpoises can set their depth of gaze accurately for the new target location. In combination, these observations imply that porpoises exert precise vocal-motor control that is tied to spatial perception akin to visual accommodation. Finally, we demonstrate that at short target ranges porpoises narrow their depth of gaze dramatically by adjusting their output so as to focus on a single target. This suggests that echolocating porpoises switch from a deliberative mode of sensorimotor operation to a reactive mode when they are close to a target.
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Affiliation(s)
- Danuta Maria Wisniewska
- Zoophysiology, Department of Bioscience, Aarhus University, Building 1131, C. F. Moellers Alle 3, DK-8000 Aarhus C, Denmark.
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Abstract
The harbor porpoise is one of the smallest and most widely spread of all toothed whales. They are found abundantly in coastal waters all around the northern hemisphere. They are among the 11 species known to use high frequency sonar of relative narrow bandwidth. Their narrow biosonar beam helps isolate echoes from prey among those from unwanted items and noise. Obtaining echoes from small objects like net mesh, net floats, and small prey is facilitated by the very high peak frequency around 130 kHz with a wavelength of about 12 mm. We argue that such echolocation signals and narrow band auditory filters give the harbor porpoise a selective advantage in a coastal environment. Predation by killer whales and a minimum noise region in the ocean around 130 kHz may have provided selection pressures for using narrow bandwidth high frequency biosonar signals.
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Affiliation(s)
- Lee A Miller
- Institute of Biology, University of Southern Denmark Odense, Denmark ; Fjord&Bælt Kerteminde, Denmark
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Koblitz JC, Wahlberg M, Stilz P, Madsen PT, Beedholm K, Schnitzler HU. Asymmetry and dynamics of a narrow sonar beam in an echolocating harbor porpoise. J Acoust Soc Am 2012; 131:2315-2324. [PMID: 22423726 DOI: 10.1121/1.3683254] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
A key component in the operation of a biosonar system is the radiation of sound energy from the sound producing head structures of toothed whales and microbats. The current view involves a fixed transmission aperture by which the beam width can only change via changes in the frequency of radiated clicks. To test that for a porpoise, echolocation clicks were recorded with high angular resolution using a 16 hydrophone array. The beam is narrower than previously reported (DI = 24 dB) and slightly dorso-ventrally compressed (horizontal -3 dB beam width: 13°, vertical -3 dB beam width: 11°). The narrow beam indicates that all smaller toothed whales investigated so far have surprisingly similar beam widths across taxa and habitats. Obtaining high directionality may thus be at least in part an evolutionary factor that led to high centroid frequencies in a group of smaller toothed whales emitting narrow band high frequency clicks. Despite the production of stereotyped narrow band high frequency clicks, changes in the directionality by a few degrees were observed, showing that porpoises can obtain changes in sound radiation.
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Affiliation(s)
- Jens C Koblitz
- Animal Physiology, Institute for Neurobiology, University of Tübingen, Auf der Morgenstelle 28, 72076 Tübingen, Germany.
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Linnenschmidt M, Beedholm K, Wahlberg M, Højer-Kristensen J, Nachtigall PE. Keeping returns optimal: gain control exerted through sensitivity adjustments in the harbour porpoise auditory system. Proc Biol Sci 2012; 279:2237-45. [PMID: 22279169 DOI: 10.1098/rspb.2011.2465] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Animals that use echolocation (biosonar) listen to acoustic signals with a large range of intensities, because echo levels vary with the fourth power of the animal's distance to the target. In man-made sonar, engineers apply automatic gain control to stabilize the echo energy levels, thereby rendering them independent of distance to the target. Both toothed whales and bats vary the level of their echolocation clicks to compensate for the distance-related energy loss. By monitoring the auditory brainstem response (ABR) during a psychophysical task, we found that a harbour porpoise (Phocoena phocoena), in addition to adjusting the sound level of the outgoing signals up to 5.4 dB, also reduces its ABR threshold by 6 dB when the target distance doubles. This self-induced threshold shift increases the dynamic range of the biosonar system and compensates for half of the variation of energy that is caused by changes in the distance to the target. In combination with an increased source level as a function of target range, this helps the porpoise to maintain a stable echo-evoked ABR amplitude irrespective of target range, and is therefore probably an important tool enabling porpoises to efficiently analyse and classify received echoes.
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Affiliation(s)
- Meike Linnenschmidt
- Institute of Biology, University of Southern Denmark, Campusvej 55, 5230 Odense M, Denmark.
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Jensen FH, Beedholm K, Wahlberg M, Bejder L, Madsen PT. Estimated communication range and energetic cost of bottlenose dolphin whistles in a tropical habitat. J Acoust Soc Am 2012; 131:582-592. [PMID: 22280620 DOI: 10.1121/1.3662067] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Bottlenose dolphins (Tursiops sp.) depend on frequency-modulated whistles for many aspects of their social behavior, including group cohesion and recognition of familiar individuals. Vocalization amplitude and frequency influences communication range and may be shaped by many ecological and physiological factors including energetic costs. Here, a calibrated GPS-synchronized hydrophone array was used to record the whistles of bottlenose dolphins in a tropical shallow-water environment with high ambient noise levels. Acoustic localization techniques were used to estimate the source levels and energy content of individual whistles. Bottlenose dolphins produced whistles with mean source levels of 146.7 ± 6.2 dB re. 1 μPa(RMS). These were lower than source levels estimated for a population inhabiting the quieter Moray Firth, indicating that dolphins do not necessarily compensate for the high noise levels found in noisy tropical habitats by increasing their source level. Combined with measured transmission loss and noise levels, these source levels provided estimated median communication ranges of 750 m and maximum communication ranges up to 5740 m. Whistles contained less than 17 mJ of acoustic energy, showing that the energetic cost of whistling is small compared to the high metabolic rate of these aquatic mammals, and unlikely to limit the vocal activity of toothed whales.
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Affiliation(s)
- Frants H Jensen
- Biology Department, Woods Hole Oceanographic Institution, Woods Hole, Massachusetts 02543, USA.
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Wahlberg M, Beedholm K, Heerfordt A, Møhl B. Characteristics of biosonar signals from the northern bottlenose whale, Hyperoodon ampullatus. J Acoust Soc Am 2011; 130:3077-3084. [PMID: 22087935 DOI: 10.1121/1.3641434] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The biosonar pulses from free-ranging northern bottlenose whales (Hyperoodon ampullatus) were recorded with a linear hydrophone array. Signals fulfilling criteria for being recorded close to the acoustic axis of the animal (a total of 10 clicks) had a frequency upsweep from 20 to 55 kHz and durations of 207 to 377 μs (measured as the time interval containing 95% of the signal energy). The source level of these signals, denoted pulses, was 175-202 dB re 1 μPa rms at 1 m. The pulses had a directionality index of at least 18 dB. Interpulse intervals ranged from 73 to 949 ms (N = 856). Signals of higher repetition rates had interclick intervals of 5.8-13.1 ms (two sequences, made up of 59 and 410 clicks, respectively). These signals, denoted clicks, had a shorter duration (43-200 μs) and did not have the frequency upsweep characterizing the pulses of low repetition rates. The data show that the northern bottlenose whale emits signals similar to three other species of beaked whale. These signals are distinct from the three other types of biosonar signals of toothed whales. It remains unclear why the signals show this grouping, and what consequences it has on echolocation performance.
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Affiliation(s)
- Magnus Wahlberg
- Fjord&Bælt and University of Southern Denmark, Margrethes Plads 1, 5300 Kerteminde, Denmark.
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Wahlberg M, Jensen FH, Soto NA, Beedholm K, Bejder L, Oliveira C, Rasmussen M, Simon M, Villadsgaard A, Madsen PT. Source parameters of echolocation clicks from wild bottlenose dolphins (Tursiops aduncus and Tursiops truncatus). J Acoust Soc Am 2011; 130:2263-2274. [PMID: 21973382 DOI: 10.1121/1.3624822] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The Indian Ocean and Atlantic bottlenose dolphins (Tursiops aduncus and Tursiops truncatus) are among the best studied echolocating toothed whales. However, almost all echolocation studies on bottlenose dolphins have been made with captive animals, and the echolocation signals of free-ranging animals have not been quantified. Here, biosonar source parameters from wild T. aduncus and T. truncatus were measured with linear three- and four-hydrophone arrays in four geographic locations. The two species had similar source parameters, with source levels of 177-228 dB re 1 μPa peak to peak, click durations of 8-72 μs, centroid frequencies of 33-109 kHz and rms bandwidths between 23 and 54 kHz. T. aduncus clicks had a higher frequency emphasis than T. truncatus. The transmission directionality index was up to 3 dB higher for T. aduncus (29 dB) as compared to T. truncatus (26 dB). The high directionality of T. aduncus does not appear to be only a physical consequence of a higher frequency emphasis in clicks, but may also be caused by differences in the internal properties of the sound production system.
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Affiliation(s)
- Magnus Wahlberg
- Fjord & Bælt and Marine Research Laboratory, University of Southern Denmark, Margrethes Plads 1, 5300 Kerteminde, Denmark.
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Eskesen IG, Wahlberg M, Simon M, Larsen ON. Comparison of echolocation clicks from geographically sympatric killer whales and long-finned pilot whales (L). J Acoust Soc Am 2011; 130:9-12. [PMID: 21786872 DOI: 10.1121/1.3583499] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The source characteristics of biosonar signals from sympatric killer whales and long-finned pilot whales in a Norwegian fjord were compared. A total of 137 pilot whale and more than 2000 killer whale echolocation clicks were recorded using a linear four-hydrophone array. Of these, 20 pilot whale clicks and 28 killer whale clicks were categorized as being recorded on-axis. The clicks of pilot whales had a mean apparent source level of 196 dB re 1 μPa pp and those of killer whales 203 dB re 1 μPa pp. The duration of pilot whale clicks was significantly shorter (23 μs, S.E.=1.3) and the centroid frequency significantly higher (55 kHz, S.E.=2.1) than killer whale clicks (duration: 41 μs, S.E.=2.6; centroid frequency: 32 kHz, S.E.=1.5). The rate of increase in the accumulated energy as a function of time also differed between clicks from the two species. The differences in duration, frequency, and energy distribution may have a potential to allow for the distinction between pilot and killer whale clicks when using automated detection routines for acoustic monitoring.
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Affiliation(s)
- Ida G Eskesen
- Institute of Biology, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark.
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Wilson M, Schack HB, Madsen PT, Surlykke A, Wahlberg M. Directional escape behavior in allis shad (Alosa alosa) exposed to ultrasonic clicks mimicking an approaching toothed whale. ACTA ACUST UNITED AC 2011; 214:22-9. [PMID: 21147965 DOI: 10.1242/jeb.043323] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Toothed whales emit high-powered ultrasonic clicks to echolocate a wide range of prey. It may be hypothesized that some of their prey species have evolved capabilities to detect and respond to such ultrasonic pulses in a way that reduces predation, akin to the situation for many nocturnal insects and echolocating bats. Using high-speed film recordings and controlled exposures, we obtained behavioural evidence that simulated toothed whale biosonar clicks elicit highly directional anti-predator responses in an ultrasound-sensitive allis shad (Alosa alosa). Ten shad were exposed to 192 dB re. 1 μPa (pp) clicks centred at 40 kHz at repetition rates of 1, 20, 50 and 250 clicks s(-1) with summed energy flux density levels of 148, 161, 165 and 172 dB re. 1 μPa(2) s. The exposures mimicked the acoustic exposure from a delphinid toothed whale in different phases of prey search and capture. The response times of allis shad were faster for higher repetition rates of clicks with the same sound pressure level. None of the fish responded to a single click, but had median response times of 182, 93 and 57 ms when exposed to click rates of 20, 50 and 250 clicks s(-1), respectively. This suggests that the ultrasound detector of allis shad is an energy detector and that shad respond faster when exposed to a nearby fast-clicking toothed whale than to a slow-clicking toothed whale far away. The findings are thus consistent with the hypothesis that shad ultrasound detection is used for reducing predation from echolocating toothed whales.
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Affiliation(s)
- Maria Wilson
- Department of Biological Sciences, Aarhus University, Building 1131, C. F. Moellers Allé, 8000 Aarhus C, Denmark.
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Christensen-Dalsgaard J, Brandt C, Wilson M, Wahlberg M, Madsen PT. Hearing in the African lungfish (Protopterus annectens): pre-adaptation to pressure hearing in tetrapods? Biol Lett 2010; 7:139-41. [PMID: 20826468 DOI: 10.1098/rsbl.2010.0636] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Lungfishes are the closest living relatives of the tetrapods, and the ear of recent lungfishes resembles the tetrapod ear more than the ear of ray-finned fishes and is therefore of interest for understanding the evolution of hearing in the early tetrapods. The water-to-land transition resulted in major changes in the tetrapod ear associated with the detection of air-borne sound pressure, as evidenced by the late and independent origins of tympanic ears in all of the major tetrapod groups. To investigate lungfish pressure and vibration detection, we measured the sensitivity and frequency responses of five West African lungfish (Protopterus annectens) using brainstem potentials evoked by calibrated sound and vibration stimuli in air and water. We find that the lungfish ear has good low-frequency vibration sensitivity, like recent amphibians, but poor sensitivity to air-borne sound. The skull shows measurable vibrations above 100 Hz when stimulated by air-borne sound, but the ear is apparently insensitive at these frequencies, suggesting that the lungfish ear is neither adapted nor pre-adapted for aerial hearing. Thus, if the lungfish ear is a model of the ear of early tetrapods, their auditory sensitivity was limited to very low frequencies on land, mostly mediated by substrate-borne vibrations.
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Affiliation(s)
- Jakob Christensen-Dalsgaard
- Center for Sound Communication, Institute of Biology, University of Southern Denmark, DK-5230 Odense M, Denmark.
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DeRuiter SL, Bahr A, Blanchet MA, Hansen SF, Kristensen JH, Madsen PT, Tyack PL, Wahlberg M. Acoustic behaviour of echolocating porpoises during prey capture. J Exp Biol 2009; 212:3100-7. [DOI: 10.1242/jeb.030825] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
SUMMARY
Porpoise echolocation has been studied previously, mainly in target detection experiments using stationed animals and steel sphere targets, but little is known about the acoustic behaviour of free-swimming porpoises echolocating for prey. Here, we used small onboard sound and orientation recording tags to study the echolocation behaviour of free-swimming trained porpoises as they caught dead, freely drifting fish. We analysed porpoise echolocation behaviour leading up to and following prey capture events,including variability in echolocation in response to vision restriction, prey species, and individual porpoise tested. The porpoises produced echolocation clicks as they searched for the fish, followed by fast-repetition-rate clicks(echolocation buzzes) when acquiring prey. During buzzes, which usually began when porpoises were about 1–2 body lengths from prey, tag-recorded click levels decreased by about 10 dB, click rates increased to over 300 clicks per second, and variability in body orientation (roll) increased. Buzzes generally continued beyond the first contact with the fish, and often extended until or after the end of prey handling. This unexplained continuation of buzzes after prey capture raises questions about the function of buzzes, suggesting that in addition to providing detailed information on target location during the capture, they may serve additional purposes such as the relocation of potentially escaping prey. We conclude that porpoises display the same overall acoustic prey capture behaviour seen in larger toothed whales in the wild,albeit at a faster pace, clicking slowly during search and approach phases and buzzing during prey capture.
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Affiliation(s)
- Stacy L. DeRuiter
- IFREMER, Service Acoustique et Sismique, B.P. 70, 29280 Plouzané,France
- Biology Department, Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA
| | - Alexander Bahr
- Massachusetts Institute of Technology, Center for Ocean Engineering, 32 Vassar Street, Cambridge, MA 02139, USA
| | | | | | | | - Peter T. Madsen
- Department of Biological Sciences, Zoophysiology, Aarhus University, C.F. Møllers Allé, Building 1131, DK-8000 Aarhus C, Denmark
- Biology Department, Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA
| | - Peter L. Tyack
- Biology Department, Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA
| | - Magnus Wahlberg
- Fjord and Baelt, Margrethes Plads 1, DK-5300 Kerteminde, Denmark
- Marine Biological Laboratory, University of Southern Denmark, Hindsholmsvej 10, 5300 Kerteminde, Denmark
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Jensen FH, Bejder L, Wahlberg M, Madsen PT. Biosonar adjustments to target range of echolocating bottlenose dolphins(Tursiops sp.) in the wild. J Exp Biol 2009; 212:1078-86. [DOI: 10.1242/jeb.025619] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
SUMMARY
Toothed whales use echolocation to locate and track prey. Most knowledge of toothed whale echolocation stems from studies on trained animals, and little is known about how toothed whales regulate and use their biosonar systems in the wild. Recent research suggests that an automatic gain control mechanism in delphinid biosonars adjusts the biosonar output to the one-way transmission loss to the target, possibly a consequence of pneumatic restrictions in how fast the sound generator can be actuated and still maintain high outputs. This study examines the relationships between target range (R), click intervals,and source levels of wild bottlenose dolphins (Tursiops sp.) by recording regular (non-buzz) echolocation clicks with a linear hydrophone array. Dolphins clicked faster with decreasing distance to the array,reflecting a decreasing delay between the outgoing echolocation click and the returning array echo. However, for interclick intervals longer than 30–40 ms, source levels were not limited by the repetition rate. Thus,pneumatic constraints in the sound-production apparatus cannot account for source level adjustments to range as a possible automatic gain control mechanism for target ranges longer than a few body lengths of the dolphin. Source level estimates drop with reducing range between the echolocating dolphins and the target as a function of 17 log(R). This may indicate either(1) an active form of time-varying gain in the biosonar independent of click intervals or (2) a bias in array recordings towards a 20 log(R) relationship for apparent source levels introduced by a threshold on received click levels included in the analysis.
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Affiliation(s)
- F. H. Jensen
- Zoophysiology, Department of Biological Sciences, Aarhus University, 8000 Aarhus C, Denmark
| | - L. Bejder
- Murdoch University Cetacean Research Unit, Centre for Fish and Fisheries Research, Murdoch University, Perth, 6150 Western Australia
| | - M. Wahlberg
- Murdoch University Cetacean Research Unit, Centre for Fish and Fisheries Research, Murdoch University, Perth, 6150 Western Australia
- Fjord and Bælt and University of Southern Denmark, Margrethes Plads 1,5300 Kerteminde, Denmark
| | - P. T. Madsen
- Zoophysiology, Department of Biological Sciences, Aarhus University, 8000 Aarhus C, Denmark
- Murdoch University Cetacean Research Unit, Centre for Fish and Fisheries Research, Murdoch University, Perth, 6150 Western Australia
- Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA
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Kyhn LA, Tougaard J, Jensen F, Wahlberg M, Stone G, Yoshinaga A, Beedholm K, Madsen PT. Feeding at a high pitch: source parameters of narrow band, high-frequency clicks from echolocating off-shore hourglass dolphins and coastal Hector's dolphins. J Acoust Soc Am 2009; 125:1783-1791. [PMID: 19275335 DOI: 10.1121/1.3075600] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Toothed whales depend on echolocation for orientation and prey localization, and source parameters of echolocation clicks from free-ranging animals therefore convey valuable information about the acoustic physiology and behavioral ecology of the recorded species. Recordings of wild hourglass (Lagenorhynchus cruciger) and Hector's dolphins (Cephalorhynchus hectori) were made in the Drake Passage (between Tierra del Fuego and the Antarctic Peninsular) and Banks Peninsular (Akaroa Harbour, New Zealand) with a four element hydrophone array. Analysis of source parameters shows that both species produce narrow band high-frequency (NBHF) echolocation clicks. Coastal Hector's dolphins produce clicks with a mean peak frequency of 129 kHz, 3 dB bandwidth of 20 kHz, 57 micros, 10 dB duration, and mean apparent source level (ASL) of 177 dB re 1 microPa(p.-p.). The oceanic hourglass dolphins produce clicks with mean peak frequency of 126 kHz, 3 dB bandwidth of 8 kHz, 116 micros, 10 dB duration, and a mean estimated ASL of 197 dB re 1 microPa(p.-p.). Thus, hourglass dolphins apparently produce clicks of higher source level, which should allow them to detect prey at more than twice the distance compared to Hector's dolphins. The observed source parameter differences within these two NBHF species may be an adaptation to a coastal cluttered environment versus a deep water, pelagic habitat.
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Affiliation(s)
- Line A Kyhn
- Department of Arctic Environment, National Environmental Research Institute, University of Aarhus, Roskilde, Denmark.
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