Phoca

Phoca (Template:IPAc-en Template:Respell)<ref>Template:Cite book</ref> 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.<ref name=Berta2012>Template:Cite journal</ref>

Species

Currently there are two confirmed members:

Image	Scientific name	Common Name	Distribution
File:Phoca largha Bering Sea 2.jpg	Phoca largha	spotted seal	Beaufort, Chukchi, Bering and Okhotsk Seas
File:Seehund2cele4.jpg	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
File:Long-necked seal.jpg	Phoca mutica	long-necked seal	unknown

Former members of Phoca:

• Histriophoca fasciata (ribbon seal)
• Pusa caspica (Caspian seal)
• Pusa hispida (ringed seal)
• Pusa sibirica (nerpa or Baikal seal)
• Pagophilus groenlandica (harp seal)

Mating ecology

File:Harbour seal breast feeding 1150144.jpg

Harbour seal breastfeeding a pup. Shortly after weaning mating will occur.

Both harbour and spotted seals are aquatically mating pinnipeds.<ref name=":0"/> Mating occurs in the water around the time when pups are weaned.<ref name=":1">Template:Cite journal</ref> Females in estrus are typically more dispersed than land-breeding pinnipeds and the distinction between foraging and reproductive behavior is less apparent.<ref>Template:Cite journal</ref> For this reason, it is difficult to study the mating patterns of this genus.<ref name=":2">Template:Cite journal</ref>

Female harbour seals start making foraging trips shortly before weaning their pup and consequently are widely dispersed when in estrus.<ref name=":3">Template:Cite journal</ref> Males restrict their range around the time females start to make these foraging trips.<ref name=":4">Template:Cite journal</ref> Harbour seals follow a polygynous mating system.<ref>Template:Cite journal</ref> More specifically it has been shown that male harbour seals partake in lek polygyny. Male seals defend underwater territories with well-defined boundaries.<ref name=":1" /><ref>Template:Cite journal</ref> The most valuable territories are near haulouts or along traffic corridors that provide maximum exposure to estrous females.<ref name=":3" /> One male will occupy an area throughout the breeding season, and they will return to the same display area in consecutive years.<ref name=":4" /> 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

Spotted seal triad during the breeding season: lanugo-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.<ref name=":5">Template:Cite journal</ref><ref name=":3" /><ref name=":2" /> Male harbour seal vocalizations consist of low-frequency broadband growls that peak in occurrence during the mating season.<ref name=":2" /> Males vocalize and display in small, distinct territories covering around 40–135 m².<ref name=":4" /> Each display area is spatially discrete and can be separated by up to 250 meters.<ref name=":4" /> Male harbour seals have considerable individual and geographic variation in their underwater vocalizations.<ref name=":5" /> Territory holders use the acoustic displays of intruders to locate and challenge invaders and will respond aggressively to a male call.<ref name=":6">Template:Cite journal</ref> Males assess each other by their vocalizations before deciding whether to respond.<ref name=":7">Nicholson, T. E. (2000). Social structure and underwater behavior of harbor seals in southern Monterey Bay, California. M.S. thesis, San Francisco State University.</ref> 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.<ref name=":2" />

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.<ref name=":6" /> 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.<ref>Template:Cite journal</ref> Aquatic courtship is long in duration and involves rolling, bubble blowing, and splashing to attract females.<ref name=":7" /><ref name=":1" /> Female choice appears to play a strong role in this mating system but it has yet to be formally studied.<ref name=":6" />

The mating system of spotted seals is quite different from harbour seals as spotted seals are serially monogamous.<ref>Template:Cite journal</ref> 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.<ref name=":0">Template:Cite book</ref> The pairs are considered to be territorial as they keep widely spaced from other spotted seals.<ref>Template:Cite journal</ref> The social group consists of an isolated adult pair and the females pup.<ref name=":0" /> 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.<ref name=":0" />