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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 LETTERS 2021; 1:031201. [PMID: 36154560 DOI: 10.1121/10.0003782] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [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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Sabinsky PF, Larsen ON, Wahlberg M, Tougaard J. Temporal and spatial variation in harbor seal (Phoca vitulina L.) roar calls from southern Scandinavia. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2017; 141:1824. [PMID: 28372059 DOI: 10.1121/1.4977999] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [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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Aerial low-frequency hearing in captive and free-ranging harbour seals (Phoca vitulina) measured using auditory brainstem responses. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2016; 202:859-868. [PMID: 27796483 PMCID: PMC5099358 DOI: 10.1007/s00359-016-1126-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2016] [Revised: 09/29/2016] [Accepted: 09/30/2016] [Indexed: 11/11/2022]
Abstract
The hearing sensitivity of 18 free-ranging and 10 captive harbour seals (Phoca vitulina) to aerial sounds was measured in the presence of typical environmental noise through auditory brainstem response measurements. A focus was put on the comparative hearing sensitivity at low frequencies. Low- and mid-frequency thresholds appeared to be elevated in both captive and free-ranging seals, but this is likely due to masking effects and limitations of the methodology used. The data also showed individual variability in hearing sensitivity with probable age-related hearing loss found in two old harbour seals. These results suggest that the acoustic sensitivity of free-ranging animals was not negatively affected by the soundscape they experienced in the wild.
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Nikolich K, Frouin-Mouy H, Acevedo-Gutiérrez A. Quantitative classification of harbor seal breeding calls in Georgia Strait, Canada. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2016; 140:1300. [PMID: 27586756 DOI: 10.1121/1.4961008] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
During breeding season, male harbor seals (Phoca vitulina) produce underwater calls used in sexual competition and advertisement. Call characteristics vary among populations, and within-population differences are thought to represent individual variation. However, vocalizations have not been described for several populations of this widely-distributed and genetically diverse species. This study describes the vocal repertoire of harbor seals from British Columbia, Canada. Underwater recordings were made near Hornby Island during the summer of 2014 using a single hydrophone. A wide variability was detected in breeding vocalizations within this single breeding site. Four candidate call types were identified, containing six subtypes. Linear discriminant analysis showed 88% agreement with subjective classification of call types, and 74% agreement for call subtypes. Classification tree analysis gave a 92% agreement with candidate call types, with all splits made on the basis of call duration. Differences in duration may have reflected individual differences among seals. This study suggests that the vocal repertoire of harbor seals in this area comprises a vocal continuum rather than discrete call types. Further work with the ability to localize calls may help to determine whether this complexity represents variability due to propagation conditions, animal orientation, or differences among individual seals.
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Affiliation(s)
- Katrina Nikolich
- Department of Biology, Western Washington University, 516 High Street, Bellingham, Washington 98225, USA
| | - Héloïse Frouin-Mouy
- JASCO Applied Sciences Canada Ltd., 2305-4464 Markham Street, Victoria, British Columbia V8Z 7X8, Canada
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Abstract
Migration is well developed among mammals, but there has been little attempt to date to review common ecological constraints that may guide the evolution of migration among mammals, nor to consider its prevalence across different taxa. Here we review several alternate hypotheses for the evolution of migration in mammals based on improvements in energetic gain and mate-finding contrasted with reduction in energetic costs or the risk of predation and parasitism. While there are well-documented examples of each across the order Mammalia, the available evidence to date most strongly supports the energy gain and predation risk hypotheses in the terrestrial realm, whereas a combined strategy of reducing energetic costs in one season but improving energetic gain in another season seems to characterize aquatic mammal species, as well as bats. We further discuss behavioral and physiological specialization and provide a taxonomic cross section of mammalian migration.
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Affiliation(s)
- T. Avgar
- Department of Integrative Biology, University of Guelph, 50 Stone Road East, Guelph, ON N1G 2W1, Canada
| | - G. Street
- Department of Integrative Biology, University of Guelph, 50 Stone Road East, Guelph, ON N1G 2W1, Canada
| | - J.M. Fryxell
- Department of Integrative Biology, University of Guelph, 50 Stone Road East, Guelph, ON N1G 2W1, Canada
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Hamilton CD, Lydersen C, Ims RA, Kovacs KM. Haul-out behaviour of the world's northernmost population of harbour seals (Phoca vitulina) throughout the year. PLoS One 2014; 9:e86055. [PMID: 24465867 PMCID: PMC3899210 DOI: 10.1371/journal.pone.0086055] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2013] [Accepted: 12/04/2013] [Indexed: 11/18/2022] Open
Abstract
The harbour seal population in Svalbard occurs at the northernmost limit of the species' range. It experiences environmental extremes far beyond the norm for this species, including an extended period of polar night and extensive sea ice cover. In 2009 and 2010, 60 harbour seals (30 pups + 30 immature/mature seals) from this population were equipped with Satellite-Relay Data Loggers (SRDLs) to study their haul-out behaviour, with a special focus on the winter period. Using a combination of Generalized Additive Mixed Models and Cox Proportional Hazard models, the influences of sex, maturity, temporal, spatial and environmental factors on haul-out behaviour were explored. All of the seals continued to haul out even through the coldest periods during the polar night, though clear seasonality in the time spent hauled out daily was displayed by both immature and mature seals. Time spent hauled out daily decreased from ∼5.2 hrs in September to ∼1.2 hrs in February in these age groups, while pups displayed less seasonality (∼2.4 hrs/day throughout most of the year). The average at-sea period also exhibited seasonality, increasing to a maximum of ∼1.6 days in February (monthly maxima for individual animals ranged from 7 to 19 days). The seals showed a strong preference to haul out at low tide when hauling out on land but not when using sea ice as a haul-out platform. A diel rhythm in haul-out behaviour was present during the months with day-night cycling and midnight sun but not during the polar night. Haul-out behaviour was impacted to a greater extent by air pressure, through its effect on wind speed, than by absolute temperature values. The extreme environment in Svalbard likely causes some physiological challenges that might impact survival rates negatively, particularly among pups. Climate warming is likely to have positive effects on Svalbard's harbour seal population.
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Affiliation(s)
- Charmain D. Hamilton
- Norwegian Polar Institute, Fram Centre, Tromsø, Norway
- Department of Arctic and Marine Biology, University of Tromsø, Tromsø, Norway
- * E-mail:
| | | | - Rolf A. Ims
- Department of Arctic and Marine Biology, University of Tromsø, Tromsø, Norway
| | - Kit M. Kovacs
- Norwegian Polar Institute, Fram Centre, Tromsø, Norway
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Charrier I, Mathevon N, Aubin T. Bearded seal males perceive geographic variation in their trills. Behav Ecol Sociobiol 2013. [DOI: 10.1007/s00265-013-1578-6] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Augé AA, Chilvers BL, Moore AB, Davis LS. Importance of studying foraging site fidelity for spatial conservation measures in a mobile predator. Anim Conserv 2013. [DOI: 10.1111/acv.12056] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- A. A. Augé
- Zoology Department; University of Otago; Dunedin New Zealand
- School of Surveying; University of Otago; Dunedin New Zealand
| | - B. L. Chilvers
- Aquatic and Threats Unit; Department of Conservation; Wellington New Zealand
| | - A. B. Moore
- School of Surveying; University of Otago; Dunedin New Zealand
| | - L. S. Davis
- Zoology Department; University of Otago; Dunedin New Zealand
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Laidre KL, Born EW, Gurarie E, Wiig Ø, Dietz R, Stern H. Females roam while males patrol: divergence in breeding season movements of pack-ice polar bears (Ursus maritimus). Proc Biol Sci 2013; 280:20122371. [PMID: 23222446 PMCID: PMC3574305 DOI: 10.1098/rspb.2012.2371] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2012] [Accepted: 11/09/2012] [Indexed: 11/12/2022] Open
Abstract
Intraspecific differences in movement behaviour reflect different tactics used by individuals or sexes to favour strategies that maximize fitness. We report movement data collected from n = 23 adult male polar bears with novel ear-attached transmitters in two separate pack ice subpopulations over five breeding seasons. We compared movements with n = 26 concurrently tagged adult females, and analysed velocities, movement tortuosity, range sizes and habitat selection with respect to sex, reproductive status and body mass. There were no differences in 4-day displacements or sea ice habitat selection for sex or population. By contrast, adult females in all years and both populations had significantly more linear movements and significantly larger breeding range sizes than males. We hypothesized that differences were related to encounter rates, and used observed movement metrics to parametrize a simulation model of male-male and male-female encounter. The simulation showed that the more tortuous movement of males leads to significantly longer times to male-male encounter, while having little impact on male-female encounter. By contrast, linear movements of females are consistent with a prioritized search for sparsely distributed prey. These results suggest a possible mechanism for explaining the smaller breeding range sizes of some solitary male carnivores compared to females.
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Affiliation(s)
- Kristin L Laidre
- Polar Science Center, APL, University of Washington, Seattle, WA 98105, USA.
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Hoffman JI, Trathan PN, Amos W. Genetic tagging reveals extreme site fidelity in territorial male Antarctic fur seals Arctocephalus gazella. Mol Ecol 2006; 15:3841-7. [PMID: 17032279 DOI: 10.1111/j.1365-294x.2006.03053.x] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Genetic tagging, the identification of individuals using their genotypes, provides a powerful tool for studying animals that are difficult to observe or identify using conventional techniques. However, despite being widely adopted by conservation biologists, the full potential of this approach has yet to be realized. Here we used genetic recapture data to quantify male site fidelity at a colony of Antarctic fur seals where an aerial walkway provides unprecedented access and individual positions are determined daily to 1 m accuracy. Because males are too large and aggressive to be captured and fitted with conventional tags, we remotely collected 770 tissue samples over eight consecutive seasons and used nine-locus microsatellite genotypes to reveal 306 genetic recaptures among 464 unique individuals. Within seasons, males are highly site-faithful, with any movements that occur tending to take place before the period when females come into oestrus. Of those males that return to breed over successive seasons, almost half return to within a body length of where they were before. The discovery of such extreme site faithfulness has implications for the population structure and mating system of fur seals and potentially other colonially breeding species.
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Affiliation(s)
- J I Hoffman
- Department of Zoology, University of Cambridge, Downing Street, Cambridge CB2 3EJ, UK.
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Van Parijs SM, Clark CW. Long-term mating tactics in an aquatic-mating pinniped, the bearded seal, Erignathus barbatus. Anim Behav 2006. [DOI: 10.1016/j.anbehav.2006.03.026] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Hayes SA, Pearse DE, Costa DP, Harvey JT, Le Boeuf BJ, Garza JC. Mating system and reproductive success in eastern Pacific harbour seals. Mol Ecol 2006; 15:3023-34. [PMID: 16911218 DOI: 10.1111/j.1365-294x.2006.02984.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Harbour seals sometimes breed along inland travel corridors where females become clustered in space and time and males establish underwater acoustic display territories similar to terrestrial arenas known as resource-based leks. Under these conditions, we predicted that higher levels of polygyny would be observed than has been previously reported for this species mating in open coast environments without travel corridors. Reproductive success (RS) of 70 males was measured using 20 microsatellite DNA loci and likelihood-based paternity analysis of 136 offspring collected over 3 years. Most males were assigned either zero or one paternity with 80% confidence. The greatest number of pups assigned to one male in a season was two. Variance in RS was higher for males than females (which are biologically limited to one offspring per year) indicating low to mild polygyny. In addition, distributions of relatedness values among pups within year classes did not differ significantly from a simulated distribution with R = 0, indicating that half-siblings were uncommon. Overall, polygyny levels were low relative to terrestrial pinniped mating systems and similar to observations from a harbour seal population along an open coast. Due to large confidence intervals associated with our results, we cannot rule out the hypothesis that a travel corridor might increase the degree of polygyny skew relative to that observed in open coast environments. Habitat appeared to influence male strategies as the most successful males in open coast environments patrolled offshore, while the most successful male in this study defended a territory along the travel corridor.
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Affiliation(s)
- Sean A Hayes
- NMFS Southwest Fisheries Science Center, 110 Shaffer Road, Santa Cruz, CA 95060, USA.
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Boness DJ, Bowen WD, Buhleier BM, Marshall GJ. Mating tactics and mating system of an aquatic-mating pinniped: the harbor seal, Phoca vitulina. Behav Ecol Sociobiol 2006. [DOI: 10.1007/s00265-006-0242-9] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Waring GT, Gilbert JR, Loftin J, Cabana N. Short-term Movements of Radio-tagged Harbor Seals in New England. Northeast Nat (Steuben) 2006. [DOI: 10.1656/1092-6194(2006)13[1:smorhs]2.0.co;2] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Bjørgesaeter A, Ugland KI, Bjørge A. Geographic variation and acoustic structure of the underwater vocalization of harbor seal (Phoca vitulina) in Norway, Sweden and Scotland. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2004; 116:2459-2468. [PMID: 15532676 DOI: 10.1121/1.1782933] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The male harbor seal (Phoca vitulina) produces broadband nonharmonic vocalizations underwater during the breeding season. In total, 120 vocalizations from six colonies were analyzed to provide a description of the acoustic structure and for the presence of geographic variation. The complex harbor seal vocalizations may be described by how the frequency bandwidth varies over time. An algorithm that identifies the boundaries between noise and signal from digital spectrograms was developed in order to extract a frequency bandwidth contour. The contours were used as inputs for multivariate analysis. The vocalizations' sound types (e.g., pulsed sound, whistle, and broadband nonharmonic sound) were determined by comparing the vocalizations' spectrographic representations with sound waves produced by known sound sources. Comparison between colonies revealed differences in the frequency contours, as well as some geographical variation in use of sound types. The vocal differences may reflect a limited exchange of individuals between the six colonies due to long distances and strong site fidelity. Geographically different vocal repertoires have potential for identifying discrete breeding colonies of harbor seals, but more information is needed on the nature and extent of early movements of young, the degree of learning, and the stability of the vocal repertoire. A characteristic feature of many vocalizations in this study was the presence of tonal-like introductory phrases that fit into the categories pulsed sound and whistles. The functions of these phrases are unknown but may be important in distance perception and localization of the sound source. The potential behavioral consequences of the observed variability may be indicative of adaptations to different environmental properties influencing determination of distance and direction and plausible different male mating tactics.
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Affiliation(s)
- Anders Bjørgesaeter
- Department of Marine Biology and Limnology, University of Oslo, Blindern, 0316 Oslo, Norway
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Growth and population parameters of the world?s northernmost harbour seals Phoca vitulina residing in Svalbard, Norway. Polar Biol 2004. [DOI: 10.1007/s00300-004-0656-7] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Van Parijs SM, Lydersen C, Kovacs KM. Effects of ice cover on the behavioural patterns of aquatic-mating male bearded seals. Anim Behav 2004. [DOI: 10.1016/j.anbehav.2003.09.013] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Evaluating the function of the male harbour seal, Phoca vitulina , roar through playback experiments. Anim Behav 2004. [DOI: 10.1016/j.anbehav.2003.06.019] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Van Parijs SM, Corkeron PJ, Harvey J, Hayes SA, Mellinger DK, Rouget PA, Thompson PM, Wahlberg M, Kovacs KM. Patterns in the vocalizations of male harbor seals. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2003; 113:3403-3410. [PMID: 12822810 DOI: 10.1121/1.1568943] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Comparative analyses of the roar vocalization of male harbor seals from ten sites throughout their distribution showed that vocal variation occurs at the oceanic, regional, population, and subpopulation level. Genetic barriers based on the physical distance between harbor seal populations present a likely explanation for some of the observed vocal variation. However, site-specific vocal variations were present between genetically mixed subpopulations in California. A tree-based classification analysis grouped Scottish populations together with eastern Pacific sites, rather than amongst Atlantic sites as would be expected if variation was based purely on genetics. Lastly, within the classification tree no individual vocal parameter was consistently responsible for consecutive splits between geographic sites. Combined, these factors suggest that site-specific variation influences the development of vocal structure in harbor seals and these factors may provide evidence for the occurrence of vocal dialects.
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Van Parijs SM, Kovacs KM. In-air and underwater vocalizations of eastern Canadian harbour seals, Phoca vitulina. CAN J ZOOL 2002. [DOI: 10.1139/z02-088] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Harbour seals, Phoca vitulina, have long been thought to be one of the least vocal pinniped species both in air and under water. However, recent studies have shown that males use underwater vocalizations intensively during the mating season. In air, harbour seals are still thought to be relatively silent. In this study we describe the vocal repertoire of Eastern Canadian harbour seals during the breeding season. Harbour seals from this area produced seven vocalization types in air and one vocalization type under water. In-air vocalizations are predominantly used by adult males during agonistic interactions. Other sex and age classes also vocalize, but less frequently. Nearest neighbour responses to in-air vocalizations were primarily agonistic when any age or sex class vocalized. In this study, seals produced an underwater roar vocalization closely resembling that produced by adult males during the mating season at other sites. Eastern Canadian harbour seals appear to be considerably more vocal when hauled out than is the norm for this species at other sites around the world.
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