Editing Pinniped (section)

===Locomotion===
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 | caption2 = [[Harbor seal]] (top) and California sea lion swimming. The former swims with its hind-flippers, the latter with its fore-flippers.
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Pinnipeds have two pairs of flippers on the front and back, the fore-flippers and hind-flippers. Their elbows and ankles are not externally visible.{{sfn|Berta|2012|p=62}} Pinnipeds are not as fast as [[cetacean]]s, typically swimming at {{convert|5|–|15|kn|0|abbr=on|lk=in}} compared to around {{convert|20|kn|0|abbr=on}} for several species of [[dolphin]]. Seals are more agile and flexible,{{sfn|Riedman|1990|pp=5}} and some otariids, such as the California sea lion, can make dorsal turns as the back of their heads can touch their hind flippers.<ref name="Fish 2003">{{Cite journal |author=Fish, F. E. |title=Maneuverability by the sea lion ''Zalophus californianus'': Turning performance of an unstable body design |doi=10.1242/jeb.00144 |journal=Journal of Experimental Biology |volume=206 |issue=4 |pages=667–74 |year=2003 |pmid=12517984|doi-access=free }}</ref> Pinnipeds have several adaptions for reducing [[Drag (physics)|drag]]. In addition to their streamlined bodies, they have smooth networks of [[Muscle fascicle|muscle bundles]] in their skin that may increase [[laminar flow]] and cut through the water. The [[Arrector pili muscle|hair erector muscles]] are absent, so their fur can be streamlined as they swim.{{sfn|Riedman|1990|pp=3–4}}

When swimming, otariids rely on their fore-flippers for locomotion in a wing-like manner similar to [[penguin]]s and [[sea turtles]]. Fore-flipper movement is not continuous, and the animal glides between each stroke.<ref name=Feldkamp>{{cite journal |last=Feldkamp |first=S.D. |year=1987 |title=Swimming in the California sea lion: morphometrics, drag and energetics |journal=[[The Journal of Experimental Biology]] |volume=131 |pages=117–135 |pmid=3694112 |url=http://jeb.biologists.org/content/131/1/117.full.pdf |issue=1|doi=10.1242/jeb.131.1.117|doi-access=free }}</ref><ref name="Fish1996">{{Cite journal |author=Fish, F. E. |title=Transitions from drag-based to lift-based propulsion in mammalian swimming |doi=10.1093/icb/36.6.628 |journal=Integrative and Comparative Biology |volume=36 |issue=6 |pages=628–41 |year=1996|doi-access=free }}</ref> Compared to terrestrial carnivorans, the fore-limb bones of otariids are reduced in length, giving them less resistance at the elbow joint as the flippers flap;{{sfn|Berta|2012|p=62–64}} the hind-flippers maneuver them.{{sfn|Riedman|1990|p=7}} Phocids and walruses swim by moving their hind-flippers and lower body from side to side, while their fore-flippers are mainly used for maneuvering.<ref name="Fish1996"/>{{sfn|Berta|2012|p=63}}<ref name=Kastelein/> Some species [[Whale surfacing behaviour#Breaching, lunging, and porpoising|leap]] out of the water, and "ride" waves.{{sfn|Riedman|1990|pp=7–8}}

Pinnipeds can move around on land, though not as well as terrestrial animals. Otariids and walruses are capable of turning their hind-flippers forward and under the body so they can "walk" on all fours.{{sfn|Riedman|1990|p=11}} The fore-flippers move along a [[Transverse plane|transverse]] plane, rather than the [[Sagittal plane|sagittal]] plane like the limbs of land mammals.<ref name=English>{{Cite journal |author=English, A. W. |title=Limb movements and locomotor function in the California sea lion (''Zalophus californianus'') |doi=10.1111/j.1469-7998.1976.tb02274.x |journal=Journal of Zoology |volume=178 |issue=3 |pages=341–364 |year=2009}}</ref> Otariids create momentum by laterally swaying their heads and necks.{{sfn|Riedman|1990|pp=11–12}}<ref name=English/> Sea lions have been recorded climbing up flights of stairs. Phocids lack the ability to walk on their hind-flippers, and must flop and wriggle their bodies forward as their fore-flippers keep them stable. In some species, the fore-flippers may act like [[Rowing (sport)|oars]] pushing against the ground. Phocids can move faster on ice, as they are able to slide.{{sfn|Riedman|1990|p=12}}