page_title: Pinniped
section_title: In captivity
hierarchical_section_title: Pinniped / Human relations / In captivity
caption_attribution_description: 兵庫県神戸市灘区にある王子動物園。 カリフォルニアアシカ と少年。(OJI Zoo located in Nada ward of Kobe City, Hyogo Prefecture. Sea lions and boy.)
context_page_description: Pinnipeds, commonly known as seals, are a widely distributed and diverse clade of carnivorous, fin-footed, semiaquatic marine mammals. They comprise the extant families Odobenidae, Otariidae, and Phocidae. There are 33 extant species of pinnipeds, and more than 50 extinct species have been described from fossils. While seals were historically thought to have descended from two ancestral lines, molecular evidence supports them as a monophyletic lineage. Pinnipeds belong to the order Carnivora and their closest living relatives are bears and the superfamily of musteloids, having diverged about 50 million years ago.
  Seals range in size from the 1 m and 45 kg Baikal seal to the 5 m and 3,200 kg southern elephant seal male, which is also the largest member of the order Carnivora. Several species exhibit sexual dimorphism. They have streamlined bodies and four limbs that are modified into flippers. Though not as fast in the water as dolphins, seals are more flexible and agile. Otariids use their front limbs primarily to propel themselves through the water, while phocids and walruses use their hind limbs.
context_section_description: Pinnipeds can be found in facilities around the world, as their large size and playfulness make them popular attractions. Seals have been kept in captivity since at least Ancient Rome and their trainability was noticed by Pliny the Elder. Zoologist Georges Cuvier noted during the 19th century that wild seals show considerable fondness for humans and stated that they are second only to some monkeys among wild animals in their easily tamability. Francis Galton noted in his landmark paper on domestication that seals were a spectacular example of an animal that would most likely never be domesticated despite their friendliness and desire for comfort due to the fact that they serve no practical use for humans.
  Some modern exhibits have rocky backgrounds with artificial haul-out sites and a pool, while others have pens with small rocky, elevated shelters where the animals can dive into their pools. More elaborate exhibits contain deep pools that can be viewed underwater with rock-mimicking cement as haul-out areas. The most common pinniped species kept in captivity is the California sea lion as it is both easy to train and adaptable. Other species popularly kept include the grey seal and harbor seal. Larger animals like walruses and Steller sea lions are much less common. Some organizations, such as the Humane Society of the United States and World Animal Protection, object to keeping pinnipeds and other marine mammals in captivity. They state that the exhibits could not be large enough to house animals that have evolved to be migratory, and a pool could never replace the size and biodiversity of the ocean. They also state that the tricks performed for audiences are "exaggerated variations of their natural behaviors" and distract the people from the animal's unnatural environment.
  California sea lions are used in military applications by the U.S. Navy Marine Mammal Program, including detecting naval mines and enemy divers. In the Persian Gulf, the animals have been trained to swim behind divers approaching a U.S. naval ship and attach a clamp with a rope to the diver's leg. Navy officials say that the sea lions can do this in seconds, before the enemy realizes what happened. Organizations like PETA believe that such operations put the animals in danger. The Navy insists that the sea lions are removed once their mission is complete.
caption: Captive sea lion at Kobe Oji Zoo Kobe, Japan
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