Editing Pinniped (section)

===Foraging and predation===
[[File:1031 california sealion wright odfw (35281910502).jpg|thumb|left|California sea lion with [[salmon]] or [[steelhead]]]]
All pinnipeds are [[carnivorous]] and [[predatory]]. As a whole, they mostly feed on fish and [[cephalopod]]s, but also consume [[crustacean]]s, [[bivalve]]s, [[zooplankton]] and [[endotherm]]ic (warm-blooded) prey like [[sea bird]]s.{{sfn|Riedman|1990|pp=144–145}} While most species have [[Generalist and specialist species|generalist]] diets, a few are specialists. Examples are [[krill]]-eating [[crabeater seal]]s, crustacean-eating [[ringed seal]]s, [[squid]] specialists like the [[Ross seal]] and southern elephant seal, and the bearded seal and walrus, which specialize on [[benthic zone|benthic]] invertebrates.<ref name="MacDonald"/>

Pinnipeds may hunt solitarily or [[cooperative hunting|cooperatively]]. The former behavior is typical when hunting non-schooling fish, immobile or sluggish invertebrates and endothermic prey. Solitary foraging species usually hunt in coastal or shallow water. An exception to this is the northern elephant seal, which hunts deep in the open ocean for fish. In addition, walruses feed solitarily but are often near other walruses in small or large groups. For large schools of fish or squid, pinnipeds such as certain otariids hunt cooperatively in large groups, locating and herding their prey. Some species, such as California and [[South American sea lion]]s, will hunt alongside sea birds and cetaceans.{{sfn|Riedman|1990|pp=166–168}}

Seals typically swallow their food whole, and will rip apart prey that is too big.<ref>{{cite journal|last1=Roffe |first1=T. J. |last2=Mate |first2=B. R. |year=1984 |title=Abundances and feeding habits of Pinnipeds in the Rogue River, Oregon |journal=The Journal of Wildlife Management |volume=48 |issue=4 |pages=1262–1274 |jstor=3801787 |doi=10.2307/3801787}}</ref>{{sfn|Riedman|1990|p=162}} The [[leopard seal]], a prolific predator of penguins, is known to violently shake its prey to death.{{sfn|Riedman|1990|p=153}} Complex serrations in the teeth of [[Filter feeder|filter-feeding species]], such as crabeater seals, allow water to leak out as they swallow their planktonic food.<ref name="MacDonald"/> The walrus is unique in that it consumes its prey by [[suction feeding]], using its tongue to suck the meat of a bivalve out of the shell.{{sfn|Berta|2012|pp=67}} While pinnipeds mostly hunt in the water, South American sea lions are known to chase down penguins on land.{{sfn|Riedman|1990|p=155}} Some species may [[Gastrolith|swallow stones or pebbles]] for reasons not understood.{{sfn|Riedman|1990|pp=161–162}} Though they can drink seawater, pinnipeds get most of their fluid intake from their food.{{sfn|Riedman|1990|pp=31–32}}
[[File:Fish8426 - Flickr - NOAA Photo Library.jpg|right|thumb|[[Leopard seal]] capturing [[emperor penguin]]]]
Pinnipeds themselves are subject to predation. Most species are preyed on by the [[orca]]. To subdue and kill seals, orcas strike them with their heads or tails—the latter causing them to fly in the air—or simply bite into them and rip them apart. They are typically hunted by groups of 10 or fewer whales, but they are occasionally hunted by larger groups or by lone individuals. All age classes may be targeted, but pups most of all. Large [[shark]]s are another major predator of pinnipeds—usually the [[great white shark]] but also the [[tiger shark]] and [[mako shark]]. Sharks usually attack by ambushing them from below. Injured seals that escape are usually able to recover from their wounds. Otariids that have been targeted in the hindquarters are more likely to survive, while phocids are more likely to survive with forequarters injures. Pinnipeds are also preyed on by terrestrial and [[pagophilic]] predators. The [[polar bear]] is a major predator of Arctic seals and walruses, particularly pups. Bears may seek out seals, or simply wait for them to come by. Other terrestrial predators include [[cougar]]s, [[brown hyena]]s and various species of [[canid]]s, which mostly target the young.<ref name=predation>Weller, D. W. "Predation on marine mammals" in {{harvnb|Perrin|Würsig|Thewissen|2009|pp=923–931}}</ref> 
[[File:Killer Whale Tipe B.jpg|thumb|left|[[Orca]] hunting a Weddell seal]]

Pinnipeds lessen the chance of predation by gathering in groups.{{sfn|Riedman|1990|p=218}} Some species are capable of inflicting damaging wounds on their attackers with their sharp canines; adult walruses are particularly risky prey for polar bears.<ref name=predation/> [[Brown fur seal]]s will even [[Mobbing (animal behavior)|mob]] white sharks.<ref>{{cite journal|last1=Stewardson|first1=C. L.|last2=Brett|first2=M|year=2000|title=Aggressive behaviour of an adult male Cape fur seal (''Arctocephalus pusillus pusillus'') towards a great white shark (''Carcharodon carcharias'')|journal=African Zoology|volume=35|issue=1|pages=147–150|doi=10.1080/15627020.2000.11407201}}</ref> When out at sea, northern elephant seals dive out of the reach of surface-hunting orcas and white sharks.<ref name=sleep>{{cite journal|author1=Mitani, Y. |author2=Andrews, R. D. |author3=Sato, K. |author4=Kato, A. |author5=Naito, Y. |author6=Costa, D. P. |year=2009 |title=Three-dimensional resting behaviour of northern elephant seals: Drifting like a falling leaf |journal=Biology Letters |volume=6 |issue=2 |pages=163–166 |doi=10.1098/rsbl.2009.0719 |pmid=19864274 |pmc=2865059}}</ref> In the Antarctic, which lacks terrestrial predators, pinniped species spend more time on the ice than their Arctic counterparts.{{sfn|Riedman|1990|p=138}}

Interspecific predation among pinnipeds does occur. The leopard seal is known to prey on many other species, especially the crabeater seal. Leopard seals typically target crabeater pups, particularly from November to January. Older crabeater seals commonly bear scars from failed leopard seal attacks; a 1977 study found that 75% of a sample of 85 individual crabeaters had these scars.<ref name=predation/><ref>{{cite journal |author1=Siniff, D. B. |author2=Bengtson, J. L. |year=1977 |title=Observations and hypotheses concerning the interactions among crabeater seals, leopard seals, and killer whales |journal=Journal of Mammalogy |volume=58 |issue=3 |pages=414–416 |jstor=1379341 |doi=10.2307/1379341}}</ref> Walruses, despite being specialized for feeding on bottom-dwelling invertebrates, occasionally prey on Arctic seals. They kill their prey with their long tusks and eat their blubber and skin. [[Steller sea lion]]s have been recorded eating harbor seals, northern fur seals and California sea lions, particularly pups and small adults. New Zealand sea lions feed on pups of some fur seal species, and the South American sea lion may prey on [[South American fur seal]]s.<ref name=predation/>