A Harp Seal × Hooded Seal Hybrid

Kovacs, Kit M.; Lydersen, Christian; Hammill, Mike O.; White, Bradley N.; Wilson, Paul J.; Malik, Sobia

doi:10.1111/j.1748-7692.1997.tb00652.x

Cited by 27 publications

(17 citation statements)

References 25 publications

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“…The mating systems of ice-breeding seals with spatially scattered distribution of females are less well known (Le Boeuf 1991). Promiscuity such as in harp seals (Pagophilus groenlandicus (Erxleben, 1777); Kovacs 1995in Kovacs et al 1997 and slight polygyny or serial monogamy (where females (or males) usually mate with a single partner in successive breeding attempts during a single breeding season but mate with several different partners during their lifetime; Clutton-Brock 1989) such as in hooded seals (Cystophora cristata (Erxleben, 1777); Boness et al 1988;McRae and Kovacs 1994) has been reported.…”

Section: Introductionmentioning

confidence: 99%

The mating system of polar bears: a genetic approach

et al. 2009

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Parentage analysis data for 583 individuals genotyped at 27 microsatellite loci were used to study the mating system of polar bears (Ursus maritimus Phipps, 1774) in the Barents Sea area. We discriminated statistically between full and half-siblings identified through only one common parent. We document for the first time multiple paternity in polar bears. We demonstrated for both sexes low fidelity to mating partners over time. We did not detect any significant difference between the age distribution of adult males at capture and the age distribution of males siring cubs. This might indicate that the male's age and size are less indicative of the reproductive success than previously thought. This is further supported by a rather long mean litter interval of 3.9 years for males siring several litters. The mating system of polar bears in the Barents Sea appears to be promiscuous, usually with a single successful father siring full siblings within a year, but with consecutive litters of a mother being fathered by different males. We discuss how population density, landscape characteristics, and adult sex ratio might influence the mating system of polar bears. This is of particular importance for management decisions such as, e.g., implementing sex ratios in hunting quotas.Résumé : Nous utilisons les résultats d'analyses de filiation portant sur 583 individus génotypés à 27 loci microsatellites, afin d'étudier le système de reproduction des ours blancs (Ursus maritimus Phipps, 1774) de la région de la Mer de Barents. Nous avons statistiquement discriminé entre les vrais-frères et soeurs et les demi-frères et soeurs identifiés par un seul parent commun. Nous documentons, pour la première fois chez les ours blancs, un cas de parenté multiple dans une même portée. Nous avons démontré une faible fidélité entre partenaires sexuels, lors de différentes reproductions, quel que soit le sexe. Nous n'avons pas détecté de différence entre la distribution des âges des mâles adultes à la capture et la distribution des âges des mâles au moment où ils sont pères. Cela pourrait indiquer que l'âge des mâles et leur taille sont une moindre indication du succès de leur reproduction qu'on ne le croyait. Cela est supporté par un intervalle moyen assez long (3,9 ans) entre les portées pour les pères ayant engendré plusieurs portées. Nos résultats indiquent que le système de reproduction des ours blancs de la mer de Barents semble lié à la promiscuité; ainsi, de manière générale, un mâle est le père de tous les petits d'une portée, mais les portées successives d'une femelle ont des pères différents. Nous discutons comment les variations de densité des populations et des caractéristiques du paysage, ainsi que le rapport des sexes des adultes peuvent influencer le système de reproduction des ours blancs. Ceci est important pour les décisions de gestion des populations, par ex. la fixation du rapport des sexes dans les quotas de chasse.

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Section: Introductionmentioning

confidence: 99%

The mating system of polar bears: a genetic approach

et al. 2009

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“…A natural comparison is with the related hooded seal, Cystophora cristata (Mouchaty et al 1995;Carr and Perry 1997;Kovacs et al 1997). These species are similar in distribution, migration, annual cycle, association with ice for breeding and moult, and population biology (Reeves and Ling 1981;Kovacs and Lavigne 1986;Boyd 1991;Atkinson 1997).…”

Section: Introductionmentioning

confidence: 99%

Baculum and testes of the hooded seal (Cystophora cristata): growth and size-scaling and their relationships to sexual selection

Miller¹,

Jones²,

Stenson³

1999

Can. J. Zool.

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Growth and size-scaling of the baculum and testes in the moderately polygynous hooded seal (Cystophora cristata) were studied using 107 specimens of known age (1 month to 28 years) from the northwestern Atlantic. Bacular growth was rapid between 2 and 5 years of age: length increased 150% and "density" (i.e., mass/length) increased 8-fold and mass 20-fold. Growth continued throughout life. In large, old (>14 years) males, the baculum averaged 20.7 cm in length, 2.1 g/cm in density, and 44.4 g in mass. Bacular length increased relative to body length until seals were about 5 years of age, after which it averaged 8.2%. Testicular growth continued until the seals were about 12 years of age. Testes from breeding males >12 years old averaged 11.2 cm in length, 4.6 cm in width, and 138 g in mass; length averaged 4.9% of body length. In males 2-5 years of age, bacular and testicular sizes were positively allometric relative to body length; in older males, bacular mass and density were positively allometric, and bacular length and testicular size isometric, relative to body length. Bacular size was mostly positively allometric relative to testicular size (bacular length exhibited some isometry). Compared with that of the related and ecologically similar harp seal (Pagophilus groenlandicus), which is presumed to have a promiscuous mating system, the baculum of the hooded seal was structurally simpler and grew more quickly but reached a relatively smaller size in adults (8.2 vs. 9.9% of body length). Relative testicular length was also smaller (4.9 vs. 5.7% of body length) and bacular density lower (2.1 vs. 2.8 g/cm) than in the harp seal. These observations suggest that intra-or inter-sexual competition via copulation is weaker in the hooded seal.Résumé : La croissance et la taille relative du baculum et des testicules ont été étudiées chez le Phoque à capuchon (Cystophora cristata), un animal modérément polygyne, par examen de 107 spécimens d'âge connu (1 mois à 28 ans) de l'Atlantique du nord-ouest. La croissance du baculum est rapide de 2 à 5 ans et accuse une augmentation de longueur de 150%, une augmentation de la « densité » par un facteur de 8 (i.e., masse/longueur) et une augmentation de la masse par un facteur de 20. La croissance se poursuit durant toute la vie. Chez les vieux mâles (>14 ans), le baculum est en moyenne de 20,7 cm de longueur, de 2,1 g/cm de densité et de 44,4 g de masse. La longueur du baculum augmente relativement à la longueur du corps jusqu'à l'âge de 5 ans environ, après quoi elle fait 8,2% de la longueur du corps. La croissance des testicules se poursuit jusqu'à l'âge de 12 ans environ. Les testicules des mâles reproducteurs de plus de 12 ans ont en moyenne 11,2 cm de longueur, 4,6 cm de largeur et 138 g de masse; leur longueur est égale en moyenne à 4,9% de la longueur du corps. Chez les mâles de 2-5 ans, la taille du baculum et celle des testicules ont une relation allométrique positive avec la longueur du corps; chez les mâles âgés, la masse et la densité du baculum sont également en rel...

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“…Hybrids among wild pinnipeds have been reported for Antarctic and subantarctic fur seals (Arctocephalus tropicalis) (Goldsworthy et al 1999), and harp and hooded seals (Cystophora cristata) (Kovacs et al 1997). Among the fur seals, hybridization rates were so high that they represented a risk to successful reestablishment of populations, but the frequency of crossing appears to be dropping as the numbers of animals recover, with site fidelity and somewhat different habitat preferences favoring breeding true, inducing declines in hybridization rates (Goldsworthy et al 2009;Lancaster et al 2010).…”

Section: Mitochondrial Dna (Mtdna) Analysismentioning

confidence: 99%