Phoca

{{Short description|Genus of carnivores}}

{{Automatic taxobox

| image = common seal.jpg

| taxon = Phoca

| authority = Linnaeus, 1758

| type_species = Phoca vitulina

| type_species_authority = Linnaeus, 1758

| subdivision_ranks = Species

| subdivision = *P. largha

  • P. vitulina
  • P. mutica?

}}

Phoca ({{IPAc-en|"|f|oU|k|@}} {{respell|FOH|kə}}){{Cite book|title=The Chambers Dictionary|publisher=Chambers|year=2003|isbn=0-550-10105-5|edition=9th|chapter=Phoca}} is a genus of the earless seals, within the family Phocidae. It now contains just two species, the common seal (or harbour seal) and the spotted seal (or largha seal). Several species formerly listed under this genus have been split into the genera Pusa, Pagophilus, and Histriophoca. Until recently, Phoca largha has been considered a subspecies of Phoca vitulina but now is considered its own species. For this reason, the fossil history of the genus is unclear, and it has formerly been used as wastebasket taxon for a number of fossils of uncertain affinity.{{cite journal |author1=Berta, A. |author2=Churchill, M. |name-list-style=amp |year=2012 |title=Pinniped Taxonomy: evidence for species and subspecies |journal=Mammal Review |volume=42 |issue=3 |pages=207–234 |doi=10.1111/j.1365-2907.2011.00193.x}}

Species

Currently there are two confirmed members:

class="wikitable"
ImageScientific nameCommon NameDistribution
120pxPhoca larghaspotted sealBeaufort, Chukchi, Bering and Okhotsk Seas
120pxPhoca vitulinacommon sealnorthern Atlantic and Pacific Oceans and the Baltic and North Seas

There is also a third unconfirmed member:

class="wikitable"
ImageScientific nameCommon NameDistribution
120pxPhoca muticalong-necked sealunknown

Former members of Phoca:

Mating ecology

File:Harbour seal breast feeding 1150144.jpg

Both harbour and spotted seals are aquatically mating pinnipeds. Mating occurs in the water around the time when pups are weaned.{{Cite journal|last=Sullivan|first=R. M.|date=1981|title=Aquatic Displays and Interactions in Harbor Seals, Phoca vitulina, with Comments on Mating Systems|journal=Journal of Mammalogy|volume=62|issue=4|pages=825–831|doi=10.2307/1380606|jstor=1380606}} Females in estrus are typically more dispersed than land-breeding pinnipeds and the distinction between foraging and reproductive behavior is less apparent.{{cite journal | last1 = Van Parijs | first1 = S. M. | last2 = Hastie | first2 = G. D. | last3 = Thompson | first3 = P. M. | year = 1999 | title = Geographical variation in temporal and spatial vocalization patterns of male harbour seals in the mating season | journal = Animal Behaviour | volume = 58 | issue = 6 | pages = 1231–1239 | doi = 10.1006/anbe.1999.1258 | pmid = 10600144 }} For this reason, it is difficult to study the mating patterns of this genus.{{Cite journal|last1=Hayes|first1=Sean A.|last2=Costa|first2=Daniel P.|last3=Harvey|first3=James T.|last4=Boeuf|first4=BURNEY J.|title=Aquatic Mating Strategies of the Male Pacific Harbor Seal (Phoca Vitulina Richardii): Are Males Defending the Hotspot?|date=2004-07-01|journal=Marine Mammal Science|language=en|volume=20|issue=3|pages=639–656|doi=10.1111/j.1748-7692.2004.tb01184.x|bibcode=2004MMamS..20..639H |issn=1748-7692}}

Female harbour seals start making foraging trips shortly before weaning their pup and consequently are widely dispersed when in estrus.{{cite journal | last1 = van Parijs | first1 = S. M. | last2 = Thompson | first2 = P. M. | last3 = Tollit | first3 = D. J. | last4 = Mackay | first4 = A. | year = 1997 | title = Distribution and activity of male harbor seals during the mating season | journal = Animal Behaviour | volume = 54 | issue = 1 | pages = 35–43 | doi = 10.1006/anbe.1996.0426 | pmid = 9268433 }} Males restrict their range around the time females start to make these foraging trips.{{cite journal | last1 = van Parijs | first1 = S. M. | last2 = Janik | first2 = V. M. | last3 = Thompson | first3 = P. M. | year = 2000 | title = Display-area size, tenure length, and site fidelity in the aquatically mating male harbour seal, Phoca vitulina| journal = Canadian Journal of Zoology| volume = 78 | issue = 12 | pages = 2209–2217 | doi = 10.1139/cjz-78-12-2209 }} Harbour seals follow a polygynous mating system.{{cite journal | last1 = Coltman | first1 = D. W. | last2 = Bowen | first2 = W. D. | last3 = Wright | first3 = J. M. | year = 1998 | title = Male mating success in an aquatically mating pinniped, the harbour seal (Phocu vitulina), assessed by micro- satellite DNA markers | journal = Molecular Ecology | volume = 7 | issue = 5 | pages = 627–638 | doi = 10.1046/j.1365-294x.1998.00373.x | pmid = 9633104 | bibcode = 1998MolEc...7..627C }} More specifically it has been shown that male harbour seals partake in lek polygyny. Male seals defend underwater territories with well-defined boundaries.{{cite journal | last1 = Hanggi | first1 = E. B. | last2 = Schusterman | first2 = R. J. | year = 1994 | title = Underwater acoustic displays and individual variation in male harbour seals, Phoca vitulina | journal = Animal Behaviour | volume = 48 | issue = 6 | pages = 1275–1283 | doi = 10.1006/anbe.1994.1363 }} The most valuable territories are near haulouts or along traffic corridors that provide maximum exposure to estrous females. One male will occupy an area throughout the breeding season, and they will return to the same display area in consecutive years. Female harbour seals receive direct benefits from being in a lek, as the congregation of males into an area makes mate selection easier because females do not have to travel as far and it also helps to reduce exposure to predators.

File:Noaa-seal7.jpg-clad pup (left), mother (center), and attending male (right in water).]]

Harbour seal males use underwater vocalizations and display dives within their aquatic territories, for both female attraction and male-male competition.{{Cite journal|last1=Van Parijs|first1=Sofie M|last2=Kovacs|first2=Kit M|date=2002-07-01|title= In-air and underwater vocalizations of eastern Canadian harbour seals, Phoca vitulina|journal= Canadian Journal of Zoology|volume=80|issue=7|pages=1173–1179|doi=10.1139/z02-088|issn=0008-4301}} Male harbour seal vocalizations consist of low-frequency broadband growls that peak in occurrence during the mating season. Males vocalize and display in small, distinct territories covering around 40–135 m2. Each display area is spatially discrete and can be separated by up to 250 meters. Male harbour seals have considerable individual and geographic variation in their underwater vocalizations. Territory holders use the acoustic displays of intruders to locate and challenge invaders and will respond aggressively to a male call.{{Cite journal|last1=Hayes|first1=Sean A.|last2=Kumar|first2=Anurag|last3=Costa|first3=Daniel P.|last4=Mellinger|first4=David K.|last5=Harvey|first5=James T.|last6=Southall|first6=Brandon L.|last7=Boeuf|first7=Burney J. Le|title=Evaluating the function of the male harbour seal, Phoca vitulina , roar through playback experiments|journal=Animal Behaviour|volume=67|issue=6|pages=1133–1139|doi=10.1016/j.anbehav.2003.06.019|year=2004}} Males assess each other by their vocalizations before deciding whether to respond.Nicholson, T. E. (2000). Social structure and underwater behavior of harbor seals in southern Monterey Bay, California. M.S. thesis, San Francisco State University. 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.

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. The hierarchies may aid in holding territories or to mate with 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.{{cite journal | last1 = Sullivan | first1 = R. M. | year = 1982 | title = Agonistic behavior and dominance relationships in the harbor seal, Phoca vitulina | journal = Journal of Mammalogy | volume = 63 | issue = 4 | pages = 554–569 | doi = 10.2307/1380260 | jstor = 1380260 }} Aquatic courtship is long in duration and involves rolling, bubble blowing, and splashing to attract females. Female choice appears to play a strong role in this mating system but it has yet to be formally studied.

The mating system of spotted seals is quite different from harbour seals as spotted seals are serially monogamous.{{cite journal | last1 = Beier | first1 = J. C. | last2 = Wartzok | first2 = D. | year = 1979 | title = Mating behavior of captive spotted seals (Phoca largha) | journal = Animal Behaviour | volume = 27 | pages = 772–781 | doi = 10.1016/0003-3472(79)90013-7 }} During the breeding season, a male will join a female approximately ten days before the female gives birth to a pup from the previous years mating.{{Cite book|doi=10.1016/B978-0-12-373553-9.00126-7|chapter=Harbor Seal and Spotted Seal|title=Encyclopedia of Marine Mammals|year=2009|last1=Burns|first1=John J.|pages=533–542|isbn=9780123735539}} The pairs are considered to be territorial as they keep widely spaced from other spotted seals.{{cite journal | last1 = Burns | first1 = J. J. | last2 = Ray | first2 = G. C. | last3 = Fay | first3 = F. H. | last4 = Shaughnessy | first4 = P. D. | year = 1972 | title = Adoption of a strange pup by the ice-inhabiting harbour seal, Phoca vitulina largha | journal = Journal of Mammalogy | volume = 53 | issue = 3 | pages = 594–598 | doi = 10.2307/1379048 | jstor = 1379048 }} The social group consists of an isolated adult pair and the females pup. 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.

References

{{Commons category|Phoca}}

{{Wikispecies|Phoca}}

{{Reflist}}

{{Carnivora|C1.}}

{{Pan-Pinnipedia|P.|state=autocollapse}}

{{Taxonbar|from=Q878742}}

{{Authority control}}

Category:Phocins

Category:Carnivoran genera

Category:Taxa named by Carl Linnaeus