Phoca
Phoca | |
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Scientific classification![]() | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Mammalia |
Order: | Carnivora |
Clade: | Pinnipedia |
Family: | Phocidae |
Tribe: | Phocini |
Genus: | Phoca Linnaeus,1758 |
Type species | |
Phoca vitulina Linnaeus,1758
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Species | |
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Phoca(/ˈfoʊkə/FOH-kə)[1]is a genus of theearless seals,within thefamily Phocidae.It now contains just two species, thecommon seal(or harbour seal) and thespotted seal(or largha seal). Several species formerly listed under this genus have been split into the generaPusa,Pagophilus,andHistriophoca.Until recently,Phoca larghahas been considered a subspecies ofPhoca vitulinabut now is considered its own species. For this reason, the fossil history of the genus is unclear, and it has formerly been used aswastebasket taxonfor a number of fossils of uncertain affinity.[2]
Species
[edit]Currently there are two confirmed members:
Image | Scientific name | Common Name | Distribution |
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Phoca largha | spotted seal | Beaufort, Chukchi, Bering and Okhotsk Seas |
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Phoca vitulina | common seal | northern Atlantic and Pacific Oceans and the Baltic and North Seas |
There is also a third unconfirmed member:
Image | Scientific name | Common Name | Distribution |
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Phoca mutica | long-necked seal | unknown |
Former members ofPhoca:
- Histriophoca fasciata(ribbon seal)
- Pusa caspica(Caspian seal)
- Pusa hispida(ringed seal)
- Pusa sibirica(nerpa orBaikal seal)
- Pagophilus groenlandica(harp seal)
Mating ecology
[edit]![](https://upload.wikimedia.org/wikipedia/commons/thumb/b/b4/Harbour_seal_breast_feeding_1150144.jpg/260px-Harbour_seal_breast_feeding_1150144.jpg)
Both harbour and spotted seals are aquatically matingpinnipeds.[3]Mating occurs in the water around the time when pups are weaned.[4]Females inestrusare typically more dispersed than land-breeding pinnipeds and the distinction between foraging and reproductive behavior is less apparent.[5]For this reason, it is difficult to study the mating patterns of this genus.[6]
Female harbour seals start making foraging trips shortly before weaning their pup and consequently are widely dispersed when in estrus.[7]Males restrict their range around the time females start to make these foraging trips.[8]Harbour seals follow apolygynousmating system.[9]More specifically it has been shown that male harbour seals partake inlek polygyny.Male seals defend underwater territories with well-defined boundaries.[4][10]The most valuable territories are nearhauloutsor along traffic corridors that provide maximum exposure to estrous females.[7]One male will occupy an area throughout the breeding season, and they will return to the same display area in consecutive years.[8]Female harbour seals receive direct benefits from being in a lek, as the congregation of males into an area makesmate selectioneasier because females do not have to travel as far and it also helps to reduce exposure to predators.
![](https://upload.wikimedia.org/wikipedia/commons/thumb/6/6a/Noaa-seal7.jpg/257px-Noaa-seal7.jpg)
Harbour seal males use underwater vocalizations and display dives within their aquatic territories, for bothfemale attraction and male-male competition.[11][7][6]Male harbour seal vocalizations consist of low-frequency broadband growls that peak in occurrence during the mating season.[6]Males vocalize and display in small, distinct territories covering around 40–135 m2.[8]Each display area is spatially discrete and can be separated by up to 250 meters.[8]Male harbour seals have considerable individual and geographic variation in their underwater vocalizations.[11]Territory holders use the acoustic displays of intruders to locate and challenge invaders and will respond aggressively to a male call.[12]Males assess each other by their vocalizations before deciding whether to respond.[13]These vocalizations are energetically expensive to produce and are honest signals of male quality and dominance. Male body condition will decline as the mating season progresses.[6]
Aquatic hierarchies in harbour seals develop before the breeding season and dominance is determined by direct male contests. These contests involve repeated confrontations between two males using surface splashing, fighting, paired somersaulting, and chasing techniques.[12]The hierarchies may aid in holding territories or tomatewith females during the breeding season. The dominance relationships are determined by size and sex, with adult males dominant to sub-adult males, and sub-adult females submissive to all other social classes.[14]Aquatic courtship is long in duration and involves rolling, bubble blowing, and splashing to attract females.[13][4]Female choice appears to play a strong role in thismating systembut it has yet to be formally studied.[12]
The mating system of spotted seals is quite different from harbour seals as spotted seals areserially monogamous.[15]During thebreeding season,a male will join a female approximately ten days before the female gives birth to a pup from the previous years mating.[3]The pairs are considered to be territorial as they keep widely spaced from other spotted seals.[16]The social group consists of an isolated adult pair and the females pup.[3]The female spotted seal receives direct benefits from the male as he provides protection for her and the pup until it is weaned. Immediately after weaning mating occurs.[3]
References
[edit]![](https://upload.wikimedia.org/wikipedia/en/thumb/4/4a/Commons-logo.svg/30px-Commons-logo.svg.png)
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- ^"Phoca".The Chambers Dictionary(9th ed.). Chambers. 2003.ISBN0-550-10105-5.
- ^Berta, A. & Churchill, M. (2012). "Pinniped Taxonomy: evidence for species and subspecies".Mammal Review.42(3): 207–234.doi:10.1111/j.1365-2907.2011.00193.x.
- ^abcdBurns, John J. (2009). "Harbor Seal and Spotted Seal".Encyclopedia of Marine Mammals.pp. 533–542.doi:10.1016/B978-0-12-373553-9.00126-7.ISBN9780123735539.
- ^abcSullivan, R. M. (1981). "Aquatic Displays and Interactions in Harbor Seals, Phoca vitulina, with Comments on Mating Systems".Journal of Mammalogy.62(4): 825–831.doi:10.2307/1380606.JSTOR1380606.
- ^Van Parijs, S. M.; Hastie, G. D.; Thompson, P. M. (1999). "Geographical variation in temporal and spatial vocalization patterns of male harbour seals in the mating season".Animal Behaviour.58(6): 1231–1239.doi:10.1006/anbe.1999.1258.PMID10600144.
- ^abcdHayes, Sean A.; Costa, Daniel P.; Harvey, James T.; Boeuf, BURNEY J. (2004-07-01). "Aquatic Mating Strategies of the Male Pacific Harbor Seal (Phoca Vitulina Richardii): Are Males Defending the Hotspot?".Marine Mammal Science.20(3): 639–656.Bibcode:2004MMamS..20..639H.doi:10.1111/j.1748-7692.2004.tb01184.x.ISSN1748-7692.
- ^abcvan Parijs, S. M.; Thompson, P. M.; Tollit, D. J.; Mackay, A. (1997). "Distribution and activity of male harbor seals during the mating season".Animal Behaviour.54(1): 35–43.doi:10.1006/anbe.1996.0426.PMID9268433.
- ^abcdvan Parijs, S. M.; Janik, V. M.; Thompson, P. M. (2000). "Display-area size, tenure length, and site fidelity in the aquatically mating male harbour seal,Phoca vitulina".Canadian Journal of Zoology.78(12): 2209–2217.doi:10.1139/cjz-78-12-2209.
- ^Coltman, D. W.; Bowen, W. D.; Wright, J. M. (1998). "Male mating success in an aquatically mating pinniped, the harbour seal (Phocu vitulina), assessed by micro- satellite DNA markers ".Molecular Ecology.7(5): 627–638.Bibcode:1998MolEc...7..627C.doi:10.1046/j.1365-294x.1998.00373.x.PMID9633104.
- ^Hanggi, E. B.; Schusterman, R. J. (1994). "Underwater acoustic displays and individual variation in male harbour seals,Phoca vitulina".Animal Behaviour.48(6): 1275–1283.doi:10.1006/anbe.1994.1363.
- ^abVan Parijs, Sofie M; Kovacs, Kit M (2002-07-01). "In-air and underwater vocalizations of eastern Canadian harbour seals, Phoca vitulina".Canadian Journal of Zoology.80(7): 1173–1179.doi:10.1139/z02-088.ISSN0008-4301.
- ^abcHayes, Sean A.; Kumar, Anurag; Costa, Daniel P.; Mellinger, David K.; Harvey, James T.; Southall, Brandon L.; Boeuf, Burney J. Le (2004). "Evaluating the function of the male harbour seal, Phoca vitulina, roar through playback experiments".Animal Behaviour.67(6): 1133–1139.doi:10.1016/j.anbehav.2003.06.019.
- ^abNicholson, T. E. (2000). Social structure and underwater behavior of harbor seals in southern Monterey Bay, California. M.S. thesis, San Francisco State University.
- ^Sullivan, R. M. (1982). "Agonistic behavior and dominance relationships in the harbor seal,Phoca vitulina".Journal of Mammalogy.63(4): 554–569.doi:10.2307/1380260.JSTOR1380260.
- ^Beier, J. C.; Wartzok, D. (1979). "Mating behavior of captive spotted seals (Phoca largha) ".Animal Behaviour.27:772–781.doi:10.1016/0003-3472(79)90013-7.
- ^Burns, J. J.; Ray, G. C.; Fay, F. H.; Shaughnessy, P. D. (1972). "Adoption of a strange pup by the ice-inhabiting harbour seal,Phoca vitulina largha".Journal of Mammalogy.53(3): 594–598.doi:10.2307/1379048.JSTOR1379048.