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Characterization of Bottlenose Dolphin (Tursiops truncatus) Sperm Based on Morphometric Traits. BIOLOGY 2021; 10:biology10050355. [PMID: 33922110 PMCID: PMC8143526 DOI: 10.3390/biology10050355] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/18/2021] [Revised: 04/08/2021] [Accepted: 04/19/2021] [Indexed: 11/19/2022]
Abstract
Simple Summary Dolphins are one of the best adapted aquatic mammalians in captivity. While these animals can reproduce naturally in aquaria, many aspects related to their reproduction are still unknown. Their behavior, sociability with humans and ability to learn make dolphins ideal subjects for investigating their reproduction features for conservation programs aimed at this aquatic species and others. It is known that dolphins use a multi-male mating strategy, in which sperm competition could play a fundamental role. This study aims to characterize the shape and dimensions of dolphin sperm from two mature males and putatively classifies them into subpopulations. Moreover, the influence of sex hormone levels (testosterone) and refrigeration (temperature and storage period) with sperm dimension was evaluated. The results indicated that sperm dimensions and shape differed between the two males studied and that the sperm of both males could be classified into two subpopulations depending on their dimensions. Moreover, both testosterone levels and refrigeration were seen to influence sperm dimensions. This investigation provides new insights into sperm competition in dolphin species, and the results could be extrapolated to other endangered aquatic mammalian species. Abstract Bottlenose dolphin (Tursiops truncatus) males follow many reproductive strategies to ensure their paternity. However, little is known about the sperm traits, including morphometric features, that contribute to their reproductive success. Our aim was to study dolphin sperm morphometry (a total of 13 parameters) in two adult males to evaluate (i) presumptive sperm subpopulations, (ii) the correlation of sperm morphometry with testosterone levels and (iii) the effect of refrigerated storage on the sperm morphometry. Sperm populations were classified into four principal components (PCs) based on morphometry (>94% of cumulative variance). The PCs clustered into two different sperm subpopulations, which differed between males. Furthermore, the levels of serum testosterone were positively correlated with the length of the midpiece but negatively correlated with head width and the principal piece, flagellum and total sperm lengths. Most of the sperm morphometric parameters changed during the storage period (day 1 vs. day 7), but only the principal piece length was affected by the storage temperature (5 °C vs. 15 °C). This is the first study to identify dolphin sperm subpopulations based on morphometry and the influence of serum testosterone and refrigeration on sperm morphometry.
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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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Nikolic N, Thompson P, de Bruyn M, Macé M, Chevalet C. Evolutionary history of a Scottish harbour seal population. PeerJ 2020; 8:e9167. [PMID: 32728487 PMCID: PMC7357561 DOI: 10.7717/peerj.9167] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Accepted: 04/19/2020] [Indexed: 12/02/2022] Open
Abstract
Efforts to conserve marine mammals are often constrained by uncertainty over their population history. Here, we examine the evolutionary history of a harbour seal (Phoca vitulina) population in the Moray Firth, northeast Scotland using genetic tools and microsatellite markers to explore population change. Previous fine-scale analysis of UK harbour seal populations revealed three clusters in the UK, with a northeastern cluster that included our Moray Firth study population. Our analysis revealed that the Moray Firth cluster is an independent genetic group, with similar levels of genetic diversity across each of the localities sampled. These samples were used to assess historic abundance and demographic events in the Moray Firth population. Estimates of current genetic diversity and effective population size were low, but the results indicated that this population has remained at broadly similar levels following the population bottleneck that occurred after post-glacial recolonization of the area.
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Affiliation(s)
- Natacha Nikolic
- ARBRE (Reunion Island Biodiversity Research Agency), Saint-Leu, La Réunion
- Génétique Physiologie et Systèmes d’Elevage - UMR1388, INRAE, Castanet Tolosan, France
| | - Paul Thompson
- Lighthouse Field Station, Sciences School of Biological Sciences, University of Aberdeen, Cromarty, United Kingdom
| | - Mark de Bruyn
- School of Life and Environmental Sciences, University of Sydney, Sydney, Australia
| | - Matthias Macé
- Laboratoire d’Anthropologie Moléculaire et d’Imagerie de Synthèse - UMR 5288, CNRS, Toulouse, France
| | - Claude Chevalet
- Génétique Physiologie et Systèmes d’Elevage - UMR1388, INRAE, Castanet Tolosan, France
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Schwarz D, Spitzer SM, Thomas AC, Kohnert CM, Keates TR, Acevedo‐Gutiérrez A. Large-scale molecular diet analysis in a generalist marine mammal reveals male preference for prey of conservation concern. Ecol Evol 2018; 8:9889-9905. [PMID: 30386584 PMCID: PMC6202700 DOI: 10.1002/ece3.4474] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2018] [Revised: 07/12/2018] [Accepted: 07/13/2018] [Indexed: 11/12/2022] Open
Abstract
Sex-specific diet information is important in the determination of predator impacts on prey populations. Unfortunately, the diet of males and females can be difficult to describe, particularly when they are marine predators. We combined two molecular techniques to describe haul-out use and prey preferences of male and female harbor seals (Phoca vitulina) from Comox and Cowichan Bay (Canada) during 2012-2013. DNA metabarcoding quantified the diet proportions comprised of prey species in harbor seal scat, and qPCR determined the sex of the individual that deposited each scat. Using 287 female and 260 male samples, we compared the monthly sex ratio with GLMs and analyzed prey consumption relative to sex, season, site, and year with PERMANOVA. The sex ratio between monthly samples differed widely in both years (range = 12%-79% males) and showed different patterns at each haul-out site. Male and female diet differed across both years and sites: Females consumed a high proportion of demersal fish species while males consumed more salmonid species. Diet composition was related to both sex and season (PERMANOVA: R 2 = 27%, p < 0.001; R 2 = 24%, p < 0.001, respectively) and their interaction (PERMANOVA: R 2 = 11%, p < 0.001). Diet differences between males and females were consistent across site and year, suggesting fundamental foraging differences, including that males may have a larger impact on salmonids than females. Our novel combination of techniques allowed for both prey taxonomic and spatiotemporal resolution unprecedented in marine predators.
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Affiliation(s)
- Dietmar Schwarz
- Department of BiologyWestern Washington UniversityBellinghamWashington
| | - Sara M. Spitzer
- Department of BiologyWestern Washington UniversityBellinghamWashington
- Present address:
Illumina Inc.San DiegoCalifornia
| | - Austen C. Thomas
- Department of Zoology and Marine Mammal Research UnitInstitute for the Oceans and FisheriesUniversity of British ColumbiaVancouverBritish ColumbiaCanada
- Smith‐RootVancouverWashington
| | | | - Theresa R. Keates
- Department of BiologyWestern Washington UniversityBellinghamWashington
- Present address:
Department of Ocean SciencesUniversity of CaliforniaSanta CruzCalifornia
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Matthews LP, Blades B, Parks SE. Female harbor seal ( Phoca vitulina) behavioral response to playbacks of underwater male acoustic advertisement displays. PeerJ 2018; 6:e4547. [PMID: 29607261 PMCID: PMC5875393 DOI: 10.7717/peerj.4547] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2017] [Accepted: 03/07/2018] [Indexed: 11/20/2022] Open
Abstract
During the breeding season, male harbor seals (Phoca vitulina) make underwater acoustic displays using vocalizations known as roars. These roars have been shown to function in territory establishment in some breeding areas and have been hypothesized to be important for female choice, but the function of these sounds remains unresolved. This study consisted of a series of playback experiments in which captive female harbor seals were exposed to recordings of male roars to determine if females respond to recordings of male vocalizations and whether or not they respond differently to roars from categories with different acoustic characteristics. The categories included roars with characteristics of dominant males (longest duration, lowest frequency), subordinate males (shortest duration, highest frequency), combinations of call parameters from dominant and subordinate males (long duration, high frequency and short duration, low frequency), and control playbacks of water noise and water noise with tonal signals in the same frequency range as male signals. Results indicate that overall females have a significantly higher level of response to playbacks that imitate male vocalizations when compared to control playbacks of water noise. Specifically, there was a higher level of response to playbacks representing dominant male vocalization when compared to the control playbacks. For most individuals, there was a greater response to playbacks representing dominant male vocalizations compared to playbacks representing subordinate male vocalizations; however, there was no statistical difference between those two playback types. Additionally, there was no difference between the playbacks of call parameter combinations and the controls. Investigating female preference for male harbor seal vocalizations is a critical step in understanding the harbor seal mating system and further studies expanding on this captive study will help shed light on this important issue.
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Affiliation(s)
- Leanna P Matthews
- Biology Department, Syracuse University, Syracuse, NY, United States of America
| | - Brittany Blades
- Oregon Coast Aquarium, Newport, OR, United States of America
| | - Susan E Parks
- Biology Department, Syracuse University, Syracuse, NY, United States of America
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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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Olsen MT, Andersen LW, Dietz R, Teilmann J, Härkönen T, Siegismund HR. Integrating genetic data and population viability analyses for the identification of harbour seal (Phoca vitulina) populations and management units. Mol Ecol 2014; 23:815-31. [DOI: 10.1111/mec.12644] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2012] [Revised: 12/11/2013] [Accepted: 12/13/2013] [Indexed: 02/05/2023]
Affiliation(s)
- Morten T. Olsen
- Department of Bioscience; Aarhus University; Frederiksborgvej 399 Roskilde DK-4000 Denmark
- Department of Biology; University of Copenhagen; Ole Maaløes Vej 5 Copenhagen N DK-2200 Denmark
- Centre for Geogenetics; Natural History Museum of Denmark; University of Copenhagen; Øster Voldgade 5-7 Copenhagen K 1350 Denmark
| | | | - Rune Dietz
- Department of Bioscience; Aarhus University; Frederiksborgvej 399 Roskilde DK-4000 Denmark
| | - Jonas Teilmann
- Department of Bioscience; Aarhus University; Frederiksborgvej 399 Roskilde DK-4000 Denmark
| | - Tero Härkönen
- Swedish Museum of Natural History; Box 50007 Stockholm S-10405 Sweden
| | - Hans R. Siegismund
- Department of Biology; University of Copenhagen; Ole Maaløes Vej 5 Copenhagen N DK-2200 Denmark
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González-Suárez M, Cassini MH. Variance in male reproductive success and sexual size dimorphism in pinnipeds: testing an assumption of sexual selection theory. Mamm Rev 2013. [DOI: 10.1111/mam.12012] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Manuela González-Suárez
- Department of Conservation Biology; Estación Biológica de Doñana CSIC; Calle Américo Vespucio s/n 41092 Sevilla Spain
| | - Marcelo H. Cassini
- Behavioural Biology Lab; IBYME-CONICET; Obligado 2490 1428 Buenos Aires Argentina
- Group of Studies in Ecology of Mammals; DCB; Universidad de Luján; Rutas 5 y 7 6700 Buenos Aires Argentina
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Wiszniewski J, Corrigan S, Beheregaray LB, Möller LM. Male reproductive success increases with alliance size in Indo-Pacific bottlenose dolphins (Tursiops aduncus). J Anim Ecol 2011; 81:423-31. [PMID: 21981240 DOI: 10.1111/j.1365-2656.2011.01910.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
1. Determining the extent of variation in male mating strategies and reproductive success is necessary to understand the fitness benefits of social and cooperative behaviour. 2. This study assesses the reproductive success of male Indo-Pacific bottlenose dolphins in a small embayment population where different behavioural strategies of males have previously been identified. Parentage for 44 sampled calves was examined using 23 microsatellite loci and one mitochondrial DNA marker. Our candidate parent pool of 70 males and 64 females contained individuals sampled from both the embayment and adjacent coastal populations. 3. A moderate level of polygyny was detected in our sample. We assigned paternity of 23 calves to 12 males at the strict 95% confidence level and an additional nine calves to two males at the 80% confidence level. The majority (92%) of successful males were identified as residents to the embayment, and 46% of offspring were located within the same social group or community as their father. 4. Our results suggest that the size of alliances was the best predictor of reproductive success for males in this population, while the strength of association among allied males, alliance stability and male ranging patterns had little influence. In line with predictions for male alliances formed between unrelated individuals, we found that reproductive skew within alliances was not large. 5. Together, our genetic and behavioural analyses demonstrate that alliance formation between male dolphins is a successful strategy to enhance reproductive output.
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Affiliation(s)
- Joanna Wiszniewski
- Department of Biological Sciences, Macquarie University, NSW 2109, Australia.
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Tatarenkov A, Healey CIM, Grether GF, Avise JC. Pronounced reproductive skew in a natural population of green swordtails, Xiphophorus helleri. Mol Ecol 2008; 17:4522-34. [PMID: 18986497 DOI: 10.1111/j.1365-294x.2008.03936.x] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
For many species in nature, a sire's progeny may be distributed among a few or many dams. This poses logistical challenges--typically much greater across males than across females--for assessing means and variances in mating success (number of mates) and reproductive success (number of progeny). Here we overcome these difficulties by exhaustively analyzing a population of green swordtail fish (Xiphophorus helleri) for genetic paternity (and maternity) using a suite of highly polymorphic microsatellite loci. Genetic analyses of 1476 progeny from 69 pregnant females and 158 candidate sires revealed pronounced skews in male reproductive success both within and among broods. These skews were statistically significant, greater than in females, and correlated in males but not in females with mating success. We also compare the standardized variances in swordtail reproductive success to the few such available estimates for other taxa, notably several mammal species with varied mating systems and degrees of sexual dimorphism. The comparison showed that the opportunity for selection on male X. helleri is among the highest yet reported in fishes, and it is intermediate compared to estimates available for mammals. This study is one of a few exhaustive genetic assessments of joint-sex parentage in a natural fish population, and results are relevant to the operation of sexual selection in this sexually dimorphic, high-fecundity species.
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Affiliation(s)
- Andrey Tatarenkov
- Department of Ecology and Evolutionary Biology, University of California, Irvine, CA 92697, USA.
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Rijks JM, Hoffman JI, Kuiken T, Osterhaus ADME, Amos W. Heterozygosity and lungworm burden in harbour seals (Phoca vitulina). Heredity (Edinb) 2008; 100:587-93. [PMID: 18398424 DOI: 10.1038/hdy.2008.18] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
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Jones CB, Milanov V, Hager R. Predictors of male residence patterns in groups of black howler monkeys. J Zool (1987) 2008. [DOI: 10.1111/j.1469-7998.2008.00412.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- C. B. Jones
- Department of Psychology, College of Basic and Applied Sciences, Fayetteville State University, Fayetteville, NC, USA
- National Evolutionary Synthesis Center (NESCent), Duke University, Durham, NC, USA
| | - V. Milanov
- Department of Mathematics and Computer Sciences, College of Basic and Applied Sciences, Fayetteville State University, Fayetteville, NC, USA
| | - R. Hager
- Faculty of Life Sciences, University of Manchester, Manchester, UK
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Frasier TR, Hamilton PK, Brown MW, Conger LA, Knowlton AR, Marx MK, Slay CK, Kraus SD, White BN. Patterns of male reproductive success in a highly promiscuous whale species: the endangered North Atlantic right whale. Mol Ecol 2007; 16:5277-93. [PMID: 17971086 DOI: 10.1111/j.1365-294x.2007.03570.x] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Parentage analyses of baleen whales are rare, and although mating systems have been hypothesized for some species, little data on realized male reproductive success are available and the patterns of male reproductive success have remained elusive for most species. Here we combine over 20 years of photo-identification data with high-resolution genetic data for the majority of individual North Atlantic right whales to assess paternity in this endangered species. There was significant skew in male reproductive success compared to what would be expected if mating was random (P < 0.001). The difference was due to an excess of males assigned zero paternities, a deficiency of males assigned one paternity, and an excess of males assigned as fathers for multiple calves. The variance in male reproductive success was high relative to other aquatically mating marine mammals, but was low relative to mammals where the mating system is based on resource- and/or mate-defence polygyny. These results are consistent with previous data suggesting that the right whale mating system represents one of the most intense examples of sperm competition in mammals, but that sperm competition on its own does not allow for the same degree of polygyny as systems where males can control access to resources and/or mates. The age distribution of assigned fathers was significantly biased towards older males (P < 0.05), with males not obtaining their first paternity until approximately 15 years of age, which is almost twice the average age of first fertilization in females (8 years), suggesting that mate competition is preventing younger males from reproducing. The uneven distribution of paternities results in a lower effective population size in this species that already has one of the lowest reported levels of genetic diversity, which may further inhibit reproductive success through mate incompatibility of genetically similar individuals.
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Affiliation(s)
- T R Frasier
- Natural Resources DNA Profiling and Forensic Centre, DNA Building, Trent University, 2140 East Bank Drive, Peterborough, ON, Canada K9J 7B8.
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Paternity analysis shows experience, not age, enhances mating success in an aquatically mating pinniped, the Weddell seal (Leptonychotes weddellii). Behav Ecol Sociobiol 2006. [DOI: 10.1007/s00265-006-0294-x] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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