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Girola E, Dunlop RA, Noad MJ. Singing humpback whales respond to wind noise, but not to vessel noise. Proc Biol Sci 2023; 290:20230204. [PMID: 37161338 PMCID: PMC10170193 DOI: 10.1098/rspb.2023.0204] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/11/2023] Open
Abstract
Animal communication systems evolved in the presence of noise generated by natural sources. Many species can increase the source levels of their sounds to maintain effective communication in elevated noise conditions, i.e. they have a Lombard response. Human activities generate additional noise in the environment creating further challenges for these animals. Male humpback whales are known to adjust the source levels of their songs in response to wind noise, which although variable is always present in the ocean. Our study investigated whether this Lombard response increases when singing males are exposed to additional noise generated by motor vessels. Humpback whale singers were recorded off eastern Australia using a fixed hydrophone array. The source levels of the songs produced while the singers were exposed to varying levels of wind noise and vessel noise were measured. Our results show that, even when vessel noise is dominant, singing males still adjust the source levels of their songs to compensate for the underlying wind noise, and do not further increase their source levels to compensate for the additional noise produced by the vessel. Understanding humpback whales' response to noise is important for developing mitigation policies for anthropogenic activities at sea.
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Affiliation(s)
- E Girola
- Cetacean Ecology Group, University of Queensland, Brisbane, Australia
- School of Veterinary Science, University of Queensland, Gatton, Australia
| | - R A Dunlop
- Cetacean Ecology Group, University of Queensland, Brisbane, Australia
- School of Biological Sciences, University of Queensland, St Lucia, Australia
| | - M J Noad
- Cetacean Ecology Group, University of Queensland, Brisbane, Australia
- School of Veterinary Science, University of Queensland, Gatton, Australia
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2
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Post-whaling shift in mating tactics in male humpback whales. Commun Biol 2023; 6:162. [PMID: 36797323 PMCID: PMC9935900 DOI: 10.1038/s42003-023-04509-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2022] [Accepted: 01/20/2023] [Indexed: 02/18/2023] Open
Abstract
Recent studies have shown behavioural plasticity in mating strategies can increase a population's ability to cope with anthropogenic impacts. The eastern Australian humpback whale population was whaled almost to extinction in the 1960s (~200 whales) and has recovered to pre-whaling numbers (>20,000 whales). Using an 18-year dataset, where the population increased from approximately 3,700 to 27,000 whales, we found that as male density increased over time, the use of mating tactics shifted towards more males engaging in non-singing physical competition over singing. Singing was the more successful tactic in earlier post-whaling years whereas non-singing behaviour was the more successful tactic in later years. Together, our study uncovers how changes in both local, and population-level male density resulted in a shift in the frequency, and fitness pay-off, of alternative mating tactics in a wild animal. This individual-level plasticity in male humpback whale mating tactics likely contributed to minimising their risk of extinction following a dramatic change in their social landscape due to whaling.
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Girola E, Dunlop RA, Noad MJ. Singing in a noisy ocean: vocal plasticity in male humpback whales. BIOACOUSTICS 2022. [DOI: 10.1080/09524622.2022.2122560] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Affiliation(s)
- E. Girola
- Cetacean Ecology and Acoustics Laboratory, School of Veterinary Science, The University of Queensland, Gatton, Australia
| | - R. A. Dunlop
- Cetacean Ecology and Acoustics Laboratory, School of Veterinary Science, The University of Queensland, Gatton, Australia
- School of Biological Sciences, The University of Queensland, St Lucia, Australia
| | - M. J. Noad
- Cetacean Ecology and Acoustics Laboratory, School of Veterinary Science, The University of Queensland, Gatton, Australia
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Kowarski K, Cerchio S, Whitehead H, Cholewiak D, Moors-Murphy H. Seasonal song ontogeny in western North Atlantic humpback whales: drawing parallels with songbirds. BIOACOUSTICS 2022. [DOI: 10.1080/09524622.2022.2122561] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Affiliation(s)
- Katie Kowarski
- JASCO Applied Sciences, Dartmouth, Nova Scotia, Canada
- Department of Biology, Dalhousie University, Halifax, Nova Scotia, Canada
| | | | - Hal Whitehead
- Department of Biology, Dalhousie University, Halifax, Nova Scotia, Canada
| | | | - Hilary Moors-Murphy
- Fisheries and Oceans, Bedford Institute of Oceanography, Dartmouth, Nova Scotia, Canada
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5
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Cognitive control of song production by humpback whales. Anim Cogn 2022; 25:1133-1149. [PMID: 36058997 DOI: 10.1007/s10071-022-01675-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Revised: 08/04/2022] [Accepted: 08/12/2022] [Indexed: 11/01/2022]
Abstract
Singing humpback whales are highly versatile vocalizers, producing complex sequences of sounds that they vary throughout adulthood. Past analyses of humpback whale song have emphasized yearly variations in structural features of songs made collectively by singers within a population with comparatively little attention given to the ways that individual singers vary consecutive songs. As a result, many researchers describe singing by humpback whales as a process in which singers produce sequences of repeating sound patterns. Here, we show that such characterizations misrepresent the degree to which humpback whales flexibly and dynamically control the production of sounds and sound patterns within song sessions. Singers recorded off the coast of Hawaii continuously morphed units along multiple acoustic dimensions, with the degree and direction of morphing varying across parallel streams of successive units. Individual singers also produced multiple phrase variants (structurally similar, but acoustically distinctive sequences) within song sessions. The precision with which individual singers maintained some acoustic properties of phrases and morphing trajectories while flexibly changing others suggests that singing humpback whales actively select and adjust acoustic elements of their songs in real time rather than simply repeating stereotyped sound patterns within song sessions.
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Carouso-Peck S, Goldstein MH, Fitch WT. The many functions of vocal learning. Philos Trans R Soc Lond B Biol Sci 2021; 376:20200235. [PMID: 34482721 DOI: 10.1098/rstb.2020.0235] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The capacity to learn novel vocalizations has evolved convergently in a wide range of species. Courtship songs of male birds or whales are often treated as prototypical examples, implying a sexually selected context for the evolution of this ability. However, functions of learned vocalizations in different species are far more diverse than courtship, spanning a range of socio-positive contexts from individual identification, social cohesion, or advertising pair bonds, as well as agonistic contexts such as territorial defence, deceptive alarm calling or luring prey. Here, we survey the diverse usages and proposed functions of learned novel signals, to build a framework for considering the evolution of vocal learning capacities that extends beyond sexual selection. For each function that can be identified for learned signals, we provide examples of species using unlearned signals to accomplish the same goals. We use such comparisons to generate hypotheses concerning when vocal learning is adaptive, given a particular suite of socio-ecological traits. Finally, we identify areas of uncertainty where improved understanding would allow us to better test these hypotheses. Considering the broad range of potential functions of vocal learning will yield a richer appreciation of its evolution than a narrow focus on a few prototypical species. This article is part of the theme issue 'Vocal learning in animals and humans'.
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7
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Dunlop RA, Noad MJ. The eavesdropping risk of conspicuous sexual signaling in humpback whales. Behav Ecol Sociobiol 2021. [DOI: 10.1007/s00265-021-03048-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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Warren VE, Constantine R, Noad M, Garrigue C, Garland EC. Migratory insights from singing humpback whales recorded around central New Zealand. ROYAL SOCIETY OPEN SCIENCE 2020; 7:201084. [PMID: 33391798 PMCID: PMC7735341 DOI: 10.1098/rsos.201084] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Accepted: 10/26/2020] [Indexed: 05/04/2023]
Abstract
The migration routes of wide-ranging species can be difficult to study, particularly at sea. In the western South Pacific, migratory routes of humpback whales between breeding and feeding areas are unclear. Male humpback whales sing a population-specific song, which can be used to match singers on migration to a breeding population. To investigate migratory routes and breeding area connections, passive acoustic recorders were deployed in the central New Zealand migratory corridor (2016); recorded humpback whale song was compared to song from the closest breeding populations of East Australia and New Caledonia (2015-2017). Singing northbound whales migrated past New Zealand from June to August via the east coast of the South Island and Cook Strait. Few song detections were made along the east coast of the North Island. New Zealand song matched New Caledonia song, suggesting a migratory destination, but connectivity to East Australia could not be ruled out. Two song types were present in New Zealand, illustrating the potential for easterly song transmission from East Australia to New Caledonia in this shared migratory corridor. This study enhances our understanding of western South Pacific humpback whale breeding population connectivity, and provides novel insights into the dynamic transmission of song culture.
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Affiliation(s)
- Victoria E. Warren
- Institute of Marine Science, Leigh Marine Laboratory, University of Auckland, 160 Goat Island Road, Leigh 0985, New Zealand
- National Institute of Water and Atmospheric Research, 301 Evans Bay Parade, Hataitai, Wellington 6021, New Zealand
- Author for correspondence: Victoria E. Warren e-mail:
| | - Rochelle Constantine
- Institute of Marine Science, Leigh Marine Laboratory, University of Auckland, 160 Goat Island Road, Leigh 0985, New Zealand
- School of Biological Sciences, University of Auckland, 3A Symonds Street, Auckland 1010, New Zealand
| | - Michael Noad
- Cetacean Ecology and Acoustics Laboratories, School of Veterinary Science, The University of Queensland, Australia
| | - Claire Garrigue
- UMR Entropie (IRD, Université de La Réunion, Université de la Nouvelle-Calédonie, IFREMER, CNRS) BP A5, 98848 Nouméa, New Caledonia
- Opération Cétacés, 98802 Noumea, New Caledonia
| | - Ellen C. Garland
- Sea Mammal Research Unit, Scottish Oceans Institute, School of Biology, University of St Andrews, Fife KY16 8LB, UK
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Mingramm FMJ, Keeley T, Whitworth DJ, Dunlop RA. Blubber cortisol levels in humpback whales (Megaptera novaeangliae): A measure of physiological stress without effects from sampling. Gen Comp Endocrinol 2020; 291:113436. [PMID: 32057910 DOI: 10.1016/j.ygcen.2020.113436] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/09/2019] [Revised: 02/01/2020] [Accepted: 02/10/2020] [Indexed: 11/19/2022]
Abstract
Baleen whales are vulnerable to environmental impacts due to low fecundity, capital breeding strategies, and their reliance on a large amount of prey resources over large spatial scales. There has been growing interest in monitoring health and physiological stress in these species but, to date, few measures have been validated. The purpose of this study was to examine whether blubber cortisol could be used as a measure of physiological stress in humpback whales. Cortisol concentrations were initially compared between live, presumably 'healthy' whales (n = 187) and deceased whales (n = 35), which had died after stranding or entanglement, or washed ashore as a carcass. Deceased whales were found to have significantly higher cortisol levels (mean ± SD; 5.47 ± 4.52 ng/g) than live whales (0.51 ± 0.14 ng/g; p < 0.001), particularly for those animals that had experienced prolonged trauma (e.g. stranding) prior to death. Blubber cortisol levels in live whales were then examined for evidence of life history-related, seasonal, or sampling-related effects. Life history group and sampling-related factors, such as encounter time and the number of biopsy sampling attempts per animal, were found to be poor predictors of blubber cortisol levels in live whales. In contrast, blubber cortisol levels varied seasonally, with whales migrating north towards the breeding grounds in winter having significantly higher levels (0.54 ± 0.21 ng/g, p = 0.016) than those migrating south towards the feeding grounds in spring (0.48 ± 1.23 ng/g). These differences could be due to additional socio-physiological stress experienced by whales during peaks in breeding activity. Overall, blubber cortisol appears to be a suitable measure of chronic physiological stress in humpback whales.
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Affiliation(s)
- Fletcher M J Mingramm
- Cetacean Ecology and Acoustics Laboratory, School of Veterinary Science, The University of Queensland, Gatton, QLD 4343, Australia; Wildlife Endocrinology Lab, School of Agriculture and Food Science, The University of Queensland, Gatton, QLD 4343, Australia.
| | - Tamara Keeley
- Wildlife Endocrinology Lab, School of Agriculture and Food Science, The University of Queensland, Gatton, QLD 4343, Australia
| | - Deanne J Whitworth
- School of Veterinary Science, The University of Queensland, Gatton, QLD 4343, Australia; Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, St Lucia, QLD 4072, Australia
| | - Rebecca A Dunlop
- Cetacean Ecology and Acoustics Laboratory, School of Veterinary Science, The University of Queensland, Gatton, QLD 4343, Australia
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Dunlop RA, McCauley RD, Noad MJ. Ships and air guns reduce social interactions in humpback whales at greater ranges than other behavioral impacts. MARINE POLLUTION BULLETIN 2020; 154:111072. [PMID: 32319903 DOI: 10.1016/j.marpolbul.2020.111072] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Revised: 03/11/2020] [Accepted: 03/11/2020] [Indexed: 06/11/2023]
Abstract
Understanding the interactions between human activity in the ocean and marine mammals is a fundamental step to developing responsible mitigation measures and informing policy. Here, the response of migrating humpback whales to vessels towing seismic air gun arrays (on or off) was quantified as a reduction in their likelihood of socially interacting (joining together). Groups were significantly less likely to participate in a joining interaction in the presence of a vessel, regardless of whether or not the air guns were active. This reduction was especially pronounced in groups within a social environment that favored joining, that is, when singing whales or other groups were nearby. Seismic survey mitigation practices are designed primarily to prevent damage to whales' hearing from close-by sources. Here, we found potentially detrimental behavioral changes at much greater ranges, and much lower received levels, than those used for current mitigation recommendations.
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Affiliation(s)
- Rebecca A Dunlop
- Cetacean Ecology and Acoustics Laboratory, School of Veterinary Science, The University of Queensland, Gatton, Queensland 4343, Australia.
| | - Robert D McCauley
- Centre Marine Science and Technology, Curtin University, GPO Box U 1987, Perth 6845, WA, Australia
| | - Michael J Noad
- Cetacean Ecology and Acoustics Laboratory, School of Veterinary Science, The University of Queensland, Gatton, Queensland 4343, Australia
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11
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Mingramm FMJ, Keeley T, Whitworth DJ, Dunlop RA. The influence of physiological status on the reproductive behaviour of humpback whales (Megaptera novaeangliae). Horm Behav 2020; 117:104606. [PMID: 31639386 DOI: 10.1016/j.yhbeh.2019.104606] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/01/2019] [Revised: 09/22/2019] [Accepted: 09/25/2019] [Indexed: 01/31/2023]
Abstract
For most cetacean species, there is little known about how an individual's physiology influences its behaviour. Humpback whales (Megaptera novaeangliae) are a good candidate to examine such links as they have a well-described distribution and behaviour, can be consistently sampled using remote biopsy systems, and have been the subject of several previous endocrine studies. The objective here was to examine whether a female humpback whale's social state (i.e. escorted by a male or not) is related to her endocrine condition, and whether male dominance ranking is related to testosterone levels. Skin and blubber biopsies were collected from the east and west Australian humpback whale populations in 2010-2016 (n = 252) at multiple times throughout the winter-spring breeding season. Steroid hormones were extracted from blubber and concentrations of progesterone (a marker for pregnancy), testosterone (a marker of male testicular activity) and oestradiol (a potential marker of ovarian activity) measured using enzyme-immunoassays. Principal escorts-the dominant males in mixed sex groups-had significantly higher blubber testosterone levels (mean ± SE; 1.43 ± 0.20 ng/g wet weight) than subordinate, secondary escorts (0.69 ± 0.06 ng/g wet weight). Females that were escorted by males typically possessed elevated blubber oestradiol levels (1.96 ± 0.25 ng/g wet weight; p = 0.014); few were considered to be pregnant (p = 0.083). 'Unescorted' females displayed characteristically lower blubber oestradiol levels (0.56 ± 0.06 ng/g wet weight). Together, these results are consistent with 'challenge hypothesis' theory and suggest the existence of associated reproductive patterns in humpback whales.
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Affiliation(s)
- F M J Mingramm
- Cetacean Ecology and Acoustics Laboratory, School of Veterinary Science, The University of Queensland, Gatton, QLD 4343, Australia; Wildlife Endocrinology Lab, School of Agriculture and Food Science, The University of Queensland, Gatton, QLD 4343, Australia.
| | - T Keeley
- Wildlife Endocrinology Lab, School of Agriculture and Food Science, The University of Queensland, Gatton, QLD 4343, Australia
| | - D J Whitworth
- School of Veterinary Science, The University of Queensland, Gatton, QLD 4343, Australia; Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, St Lucia, QLD 4072, Australia
| | - R A Dunlop
- Cetacean Ecology and Acoustics Laboratory, School of Veterinary Science, The University of Queensland, Gatton, QLD 4343, Australia
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12
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Makowicz A, Murray L, Schlupp I. Size, species and audience type influence heterospecific female–female competition. Anim Behav 2020. [DOI: 10.1016/j.anbehav.2019.11.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Dunlop RA. The effects of vessel noise on the communication network of humpback whales. ROYAL SOCIETY OPEN SCIENCE 2019; 6:190967. [PMID: 31827838 PMCID: PMC6894609 DOI: 10.1098/rsos.190967] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2019] [Accepted: 10/24/2019] [Indexed: 05/12/2023]
Abstract
Humpback whales rely on acoustic communication to mediate social interactions. The distance to which these social signals propagate from the signaller defines its communication space, and therefore communication network (number of potential receivers). As humpback whales migrate along populated coastlines, they are likely to encounter noise from vessel traffic which will mask their social signals. Since no empirical data exist on baleen whale hearing, the consequences of this are usually assumed, being the modelled reduction in their communication space. Here, the communication space and network of migrating humpback whales was compared in increasing wind-dominated and vessel-dominated noise. Behavioural data on their social interactions were then used to inform these models. In typical wind noise, a signaller's communication space was estimated to extend to 4 km, which agreed with the maximum separation distance between groups that socially interacted. An increase in vessel noise reduced the modelled communication area, along with a significant reduction in group social interactions, probably due to a reduction in their communication network. However, signal masking did not fully explain this change in social behaviour, implying there was also an additional effect of the physical presence of the vessel on signaller and receiver behaviour. Though these observed changes in communication space and social behaviour were likely to be short term and localized, an increase in vessel activity due to tourism and coastal population growth may cause more sustained changes along the humpback whale migration paths.
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Affiliation(s)
- Rebecca A. Dunlop
- Cetacean Ecology and Acoustics Laboratory, School of Veterinary Science, University of Queensland, Gatton Campus, Gatton, Queensland 4343, Australia
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Madhusudhana SK, Chakraborty B, Latha G. Humpback whale singing activity off the Goan coast in the Eastern Arabian Sea. BIOACOUSTICS 2019. [DOI: 10.1080/09524622.2018.1458248] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Affiliation(s)
| | | | - G. Latha
- National Institute of Ocean Technology, Chennai, India
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15
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Girola E, Noad MJ, Dunlop RA, Cato DH. Source levels of humpback whales decrease with frequency suggesting an air-filled resonator is used in sound production. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2019; 145:869. [PMID: 30823805 DOI: 10.1121/1.5090492] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2018] [Accepted: 01/25/2019] [Indexed: 05/26/2023]
Abstract
Source level and frequency are important in determining how far an acoustic signal can travel. However, in some species these sound characteristics have been found to be biomechanically linked, and therefore cannot be modified independently to achieve optimal transmission. This study investigates the variability in source levels and their relationship with frequency in the songs of humpback whales (Megaptera novaeangliae). Songs were recorded off eastern Australia using a fixed hydrophone array deployed on the whales' migratory corridor. Singing whales were acoustically tracked. An empirical, frequency-dependent model was used to estimate transmission loss. Source levels and frequency were measured for 2408 song units from 19 singers. Source levels varied from 138 to 187 dB re 1 μPa at 1 m (root mean squared), while peak frequency ranged between 52 and 3877 Hz. Much of the variability in source levels was accounted for by differences between the unit types, with mean source levels for each unit type varying by up to 17 dB. Source levels were negatively correlated with peak frequency and decreased by 2.3 dB per octave. The negative correlation between source levels and frequency is consistent with the presence of an air-filled resonator in the whales' sound production system.
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Affiliation(s)
- Elisa Girola
- Cetacean Ecology and Acoustics Laboratory, School of Veterinary Science, University of Queensland, Gatton, Queensland 4343, Australia
| | - Michael J Noad
- Cetacean Ecology and Acoustics Laboratory, School of Veterinary Science, University of Queensland, Gatton, Queensland 4343, Australia
| | - Rebecca A Dunlop
- Cetacean Ecology and Acoustics Laboratory, School of Veterinary Science, University of Queensland, Gatton, Queensland 4343, Australia
| | - Douglas H Cato
- School of Geosciences, University of Sydney, Sydney, New South Wales 2006, Australia
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Song variation of the South Eastern Indian Ocean pygmy blue whale population in the Perth Canyon, Western Australia. PLoS One 2019; 14:e0208619. [PMID: 30668600 PMCID: PMC6342329 DOI: 10.1371/journal.pone.0208619] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2018] [Accepted: 11/20/2018] [Indexed: 11/19/2022] Open
Abstract
Sea noise collected over 2003 to 2017 from the Perth Canyon, Western Australia was analysed for variation in the South Eastern Indian Ocean pygmy blue whale song structure. The primary song-types were: P3, a three unit phrase (I, II and III) repeated with an inter-song interval (ISI) of 170-194 s; P2, a phrase consisting of only units II & III repeated every 84-96 s; and P1 with a phrase consisting of only unit II repeated every 45-49 s. The different ISI values were approximate multiples of each other within a season. When comparing data from each season, across seasons, the ISI value for each song increased significantly through time (all fits had p << 0.001), at 0.30 s/Year (95%CI 0.217-0.383), 0.8 s/Year (95%CI 0.655-1.025) and 1.73 s/Year (95%CI 1.264-2.196) for the P1, P2 and P3 songs respectively. The proportions of each song-type averaged at 21.5, 24.2 and 56% for P1, P2 and P3 occurrence respectively and these ratios could vary by up to ± 8% (95% CI) amongst years. On some occasions animals changed the P3 ISI to be significantly shorter (120-160 s) or longer (220-280 s). Hybrid song patterns occurred where animals combined multiple phrase types into a repeated song. In recent years whales introduced further complexity by splitting song units. This variability of song-type and proportions implies abundance measure for this whale sub population based on song detection needs to factor in trends in song variability to make data comparable between seasons. Further, such variability in song production by a sub population of pygmy blue whales raises questions as to the stability of the song types that are used to delineate populations. The high level of song variability may be driven by an increasing number of background whale callers creating 'noise' and so forcing animals to alter song in order to 'stand out' amongst the crowd.
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Dunlop RA. The communication space of humpback whale social sounds in wind-dominated noise. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2018; 144:540. [PMID: 30180684 DOI: 10.1121/1.5047744] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
In animal social networks, a large acoustic communication space tends to involve complex networks. Signal masking may reduce this space, leading to detrimental effects on the animal's ability to obtain important social information. Humpback whales use acoustic social sounds (vocal sounds and surface-generated sounds from breaching or fin slapping) for within- and between-group communication. In this study, changes in various sound parameters (e.g., signal-above-noise and frequency content) of received humpback whale social sounds were statistically modeled against the combined effect of increasing wind-dominated noise and distance from the source (whale) to produce masking models. Behavioral data on vocalizing groups were also used to inform these models. The acoustic communication space, in this shallow water (<50 m) environment, extended to approximately 4 km from the signaler in median wind noise. However, the majority of behavioral interactions occurred within 2 km of the signaler. Surface-generated signals propagated better and likely function to maintain this space in higher wind noise. This study provides a basic wind-noise masking model for social communication signals in humpback whales which can be updated as more information on humpback auditory capabilities, and potential masking effects of anthropogenic noise sources, becomes available.
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Affiliation(s)
- Rebecca A Dunlop
- Cetacean Ecology and Acoustics Laboratory, School of Veterinary Science, University of Queensland, Gatton Campus, Queensland, QLD 4343, Australia
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18
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Fournet ME, Jacobsen L, Gabriele CM, Mellinger DK, Klinck H. More of the same: allopatric humpback whale populations share acoustic repertoire. PeerJ 2018; 6:e5365. [PMID: 30083470 PMCID: PMC6071617 DOI: 10.7717/peerj.5365] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2018] [Accepted: 07/11/2018] [Indexed: 11/20/2022] Open
Abstract
BACKGROUND Humpback whales (Megaptera novaeangliae) are a widespread, vocal baleen whale best known for producing song, a complex, repetitive, geographically distinct acoustic signal sung by males, predominantly in a breeding context. Humpback whales worldwide also produce non-song vocalizations ("calls") throughout their migratory range, some of which are stable across generations. METHODS We looked for evidence that temporally stable call types are shared by two allopatric humpback whale populations while on their northern hemisphere foraging grounds in order to test the hypothesis that some calls, in strong contrast to song, are innate within the humpback whale acoustic repertoire. RESULTS Despite being geographically and genetically distinct populations, humpback whales in Southeast Alaska (North Pacific Ocean) share at least five call types with conspecifics in Massachusetts Bay (North Atlantic Ocean). DISCUSSION This study is the first to identify call types shared by allopatric populations, and provides evidence that some call types may be innate.
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Affiliation(s)
- Michelle E.H. Fournet
- Department of Fisheries and Wildlife, Oregon State University, Corvallis, OR, United States of America
- Cooperative Institute of Marine Resource Studies, Oregon State University and NOAA Pacific Marine Environmental Laboratory, Newport, OR, United States of America
| | - Lauren Jacobsen
- Bioacoustics Research Program, Cornell Lab of Ornithology, Cornell University, Ithaca, NY, United States of America
| | - Christine M. Gabriele
- Humpback Whale Monitoring Program, Glacier Bay National Park and Preserve, Gustavus, AK, United States of America
| | - David K. Mellinger
- Cooperative Institute of Marine Resource Studies, Oregon State University and NOAA Pacific Marine Environmental Laboratory, Newport, OR, United States of America
| | - Holger Klinck
- Bioacoustics Research Program, Cornell Lab of Ornithology, Cornell University, Ithaca, NY, United States of America
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19
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Abstract
Why do humpback whales sing? This paper considers the hypothesis that humpback whales may use song for long range sonar. Given the vocal and social behavior of humpback whales, in several cases it is not apparent how they monitor the movements of distant whales or prey concentrations. Unless distant animals produce sounds, humpback whales are unlikely to be aware of their presence or actions. Some field observations are strongly suggestive of the use of song as sonar. Humpback whales sometimes stop singing and then rapidly approach distant whales in cases where sound production by those whales is not apparent, and singers sometimes alternately sing and swim while attempting to intercept another whale that is swimming evasively. In the evolutionary development of modern cetaceans, perceptual mechanisms have shifted from reliance on visual scanning to the active generation and monitoring of echoes. It is hypothesized that as the size and distance of relevant events increased, humpback whales developed adaptive specializations for long-distance echolocation. Differences between use of songs by humpback whales and use of sonar by other echolocating species are discussed, as are similarities between bat echolocation and singing by humpback whales. Singing humpback whales are known to emit sounds intense enough to generate echoes at long ranges, and to flexibly control the timing and qualities of produced sounds. The major problem for the hypothesis is the lack of recordings of echoes from other whales arriving at singers immediately before they initiate actions related to those whales. An earlier model of echoic processing by singing humpback whales is here revised to incorporate recent discoveries. According to the revised model, both direct echoes from targets and modulations in song-generated reverberation can provide singers with information that can help them make decisions about future actions related to mating, traveling, and foraging. The model identifies acoustic and structural features produced by singing humpback whales that may facilitate a singer's ability to interpret changes in echoic scenes and suggests that interactive signal coordination by singing whales may help them to avoid mutual interference. Specific, testable predictions of the model are presented.
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Affiliation(s)
- Eduardo Mercado III
- Department of Psychology, University at Buffalo, The State University of New York, Buffalo, NY, United States
- Evolution, Ecology, and Behavior Program, University at Buffalo, The State University of New York, Buffalo, NY, United States
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Cholewiak DM, Cerchio S, Jacobsen JK, Urbán-R. J, Clark CW. Songbird dynamics under the sea: acoustic interactions between humpback whales suggest song mediates male interactions. ROYAL SOCIETY OPEN SCIENCE 2018; 5:171298. [PMID: 29515847 PMCID: PMC5830736 DOI: 10.1098/rsos.171298] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2017] [Accepted: 01/10/2018] [Indexed: 06/08/2023]
Abstract
The function of song has been well studied in numerous taxa and plays a role in mediating both intersexual and intrasexual interactions. Humpback whales are among few mammals who sing, but the role of sexual selection on song in this species is poorly understood. While one predominant hypothesis is that song mediates male-male interactions, the mechanism by which this may occur has never been explored. We applied metrics typically used to assess songbird interactions to examine song sequences and movement patterns of humpback whale singers. We found that males altered their song presentation in the presence of other singers; focal males increased the rate at which they switched between phrase types (p = 0.005), and tended to increase the overall evenness of their song presentation (p = 0.06) after a second male began singing. Two-singer dyads overlapped their song sequences significantly more than expected by chance. Spatial analyses revealed that change in distance between singers was related to whether both males kept singing (p = 0.012), with close approaches leading to song cessation. Overall, acoustic interactions resemble known mechanisms of mediating intrasexual interactions in songbirds. Future work should focus on more precisely resolving how changes in song presentation may be used in competition between singing males.
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Affiliation(s)
- Danielle M. Cholewiak
- Protected Species Branch, Northeast Fisheries Science Center, National Oceanic and Atmospheric Administration/National Marine Fisheries Service, Woods Hole, MA, USA
- Department of Neurobiology and Behavior and the Bioacoustics Research Program, Cornell Laboratory of Ornithology, Cornell University, Ithaca, NY, USA
| | - Salvatore Cerchio
- New England Aquarium, Boston, MA, USA
- Woods Hole Oceanographic Institution, Woods Hole, MA, USA
| | - Jeff K. Jacobsen
- Department of Biological Sciences, Humboldt State University, Arcata, CA, USA
| | - Jorge Urbán-R.
- Programa de Investigación de Mamíferos Marinos, Departamento de Biología Marina, Universidad Autónoma de Baja California Sur, La Paz, BCS, México
| | - Christopher W. Clark
- Department of Neurobiology and Behavior and the Bioacoustics Research Program, Cornell Laboratory of Ornithology, Cornell University, Ithaca, NY, USA
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21
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Noad MJ, Dunlop RA, Mack AK. Changes in humpback whale singing behavior with abundance: Implications for the development of acoustic surveys of cetaceans. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2017; 142:1611. [PMID: 28964095 DOI: 10.1121/1.5001502] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Acoustic surveys of vocal animals can have significant advantages over visual surveys, particularly for marine mammals. For acoustic density estimates to be viable, however, the vocal output of the animals surveyed needs to be determined under a range of conditions and shown to be a robust predictor of abundance. In this study, the songs of humpback whales, one of the most vocal and best studied species of marine mammals, were tested as predictors of abundance. Two acoustic metrics, the number of singing whales and amount of songs produced, were compared with the number of whales seen traversing a study site on the eastern coast of Australia over an 18 year period. Although there were predictive relationships between both metrics and numbers of passing whales, these relationships changed significantly as the population grew in size. The proportion of passing whales that sang decreased as the population increased. Singing in humpback whales, therefore, is a poor predictor even of relative abundance and illustrates the caution required when developing acoustic survey techniques particularly when using social vocalizations.
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Affiliation(s)
- Michael J Noad
- Cetacean Ecology and Acoustics Laboratory, School of Veterinary Science, The University of Queensland, Gatton, Queensland 4343, Australia
| | - Rebecca A Dunlop
- Cetacean Ecology and Acoustics Laboratory, School of Veterinary Science, The University of Queensland, Gatton, Queensland 4343, Australia
| | - Amelia K Mack
- Cetacean Ecology and Acoustics Laboratory, School of Veterinary Science, The University of Queensland, Gatton, Queensland 4343, Australia
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