Pinniped

**Pinnipeds**  are the **seals** and their relatives, a group of semi-aquatic marine mammals. The **Pinnipedia** is in the Order Carnivora. 
There are three seal families: Odobenidae (walruses), Otariidae (eared seals, including sea lions and fur seals), and Phocidae (true seals). 

Seals are sleek-bodied and barrel-shaped. Their bodies are well adapted to the aquatic habitat where they spend most of their lives. Pinnipeds have flippers for hands, big bulky bodies, doggish faces, and big eyes. Unlike cetaceans, pinnipeds have their noses on their faces, and each nostril of the nose closes when the pinniped goes underwater. Like cetaceans, pinnipeds have a thick layer of blubber (fat) just under their skin: this blubber keeps them warm in cold waters and keeps them fed during times when food is not easily found. When they cannot find food, they live off the fat in the blubber.

Pinnipeds are carnivorous. This means they eat only meat (such as fish or squid) and not plants. However, almost all pinnipeds can be eaten by polar bears, sharks and killer whales.

Seals are often trained in zoos or aquariums to put on shows. However, in Sweden, it is illegal to train a seal to balance a ball on its nose.

## Sleep 
Pinnipeds sleep in the water. They may also sleep on land. In both environments, there is a danger. At least in the northern hemisphere, there is danger from polar bears on land, and in the water, there is danger from sharks. While sleeping in water, the animals go through different stages of sleep. They do some behaviors during sleep: they come to the surface occasionally to breathe, and they now and then open an eye for a period of time. The details vary in different species or groups. Similar adaptations are found in cetaceans like dolphins.

## Taxonomy 
* Family **Phocidae** (Earless seals or true seals)
** Subfamily Monachinae
*** Tribe **Monachini**
**** Genus *Monachus*
*** Tribe Mirungaini
**** Genus *Mirounga*: Elephant seals
*** Tribe **Lobodontini**
**** Genus *Ommatophoca*
***** Ross seal (*Ommatophoca rossii*)
**** Genus *Lobodon*
***** Crabeater seal (*Lobodon carcinophagus*)
**** Genus *Hydrurga*
***** Leopard seal (*Hydrurga leptonyx*)
**** Genus *Leptonychotes*
***** Weddell seal (*Leptonychotes weddellii*)
** Subfamily **Phocinae**
*** (*placed here*)
**** Genus *Cystophora*
***** Hooded seal (*Cystophora cristata*)
**** Genus *Erignathus*
***** Bearded seal (*Erignathus barbatus*)
*** Tribe **Phocini**
**** Genus *Histriophoca* 
*****Ribbon seal (*Histriophoca fasciata*)
**** Genus *Phoca*
***** Spotted seal (*Phoca largha*)
***** Common seal or Harbor Seal (*Phoca vitulina*)
***** Harp seal (*Phoca groenlandica*, formerly *Pagophilus groenlandicus*)
**** Genus *Pusa*
***** Ringed seal (*Pusa hispida*, formerly *Phoca hispida*)
***** Caspian seal (*Pusa caspica*, formerly *Phoca caspica*)
***** Baikal seal or Nerpa (*Pusa sibirica*, formerly *Phoca sibirica*)
**** Genus *Halichoerus*
***** Grey seal (*Halichoerus grypus*)

* Family **Otariidae** (Eared seals)
** Genus *Arctocephalus* (Fur seals)
*** Antarctic fur seal (*Arctocephalus gazella*)
*** Brown fur seal (*Arctocephalus pusillus*)
** Genus *Callorhinus*
*** Northern fur seal (*Callorhinus ursinus*)
** Genus *Eumetopias*
*** Steller sea lion or Northern Sea Lion (*Eumetopias jubatus*)
** Genus *Neophoca*
*** Australian sea lion (*Neophoca cinerea*) 
** Genus *Otaria*
*** South American sea lion or Southern Sea Lion (*Otaria flavescens*, formerly *Otaria byronia*) 
** Genus *Phocarctos*
*** New Zealand sea lion (*Phocarctos hookeri*)
** Genus *Zalophus*
*** California sea lion (*Zalophus californianus*)

* Family **Odobenidae** (Walruses)
** Walrus (*Odobenus rosmarus*)

## References