Eared seal

Eared seals, also called otariids or otaries, are a group of marine mammals that include sea lions and fur seals. They belong to the family Otariidae, one of three families of pinnipeds, which are animals adapted to life in water and on land. There are 15 living species of eared seals, split into seven groups, and they live in subpolar, temperate, and equatorial waters of the Pacific, Southern, Indian, and Atlantic Oceans. Unlike true seals and walruses, eared seals have small, visible ear flaps, which is why their name comes from the Ancient Greek word for "little ear." These animals spend much of their time in the water hunting for food and traveling, but they come to land or ice to rest and raise their young.

Evolution and taxonomy

Morphological and molecular evidence supports a monophyletic origin of pinnipeds, sharing a common ancestor with Musteloidea. Otariids arose in the Miocene (15–17 million years ago) in the North Pacific, diversifying rapidly into the Southern Hemisphere, where most species now live. The earliest known fossil otariid is Eotaria crypta from southern California, while the genus Callorhinus (northern fur seal) has the oldest fossil record of any living otariid, extending to the middle Pliocene.

Traditionally, otariids had been subdivided into the fur seal (Arctocephalinae) and sea lion (Otariinae) subfamilies, but recent analyses of the genetic evidence suggest that some groupings may be more closely related than previously thought. In light of this evidence, the family Otariidae has been organized into seven genera with 16 species and two subspecies. Fur seals are generally smaller, show greater sexual dimorphism, eat smaller prey, and go on longer foraging trips compared to sea lions.

Anatomy

Otariids, also known as eared seals, have small ear flaps called pinnae that you can see. They have larger front flippers and stronger chest muscles than true seals, and they can turn their back legs forward to walk on all fours, which makes them very nimble on land.

Although they spend less time in the water than true seals, otariids can swim very fast and turn quickly because they use their flippers to push through the water. They look more like dogs with sharp teeth and visible ears. Male otariids can be much bigger than females, ranging from the smaller Galápagos fur seal to the very large Steller sea lion.

Behavior

Eared seals, also known as sea lions and fur seals, have specific ways of living and caring for their young. They usually come together on beaches or rocky areas, often on islands, to have their babies during set times of the year. Most of these seals pick one male to stay with many females during this time. The males often show off or make loud sounds to claim their area. The females usually arrive a little before they give birth.

These seals eat fish, squid, and krill. Some stay closer to the shore to catch bigger fish, while others go farther out to find lots of smaller food. They hunt using their sight and can dive very deep to find their meals.

Species

Family Otariidae

• Subfamily Arctocephalinae (fur seals)

  • Genus Arctocephalus
    • Brown fur seal, A. pusillus
      • South African fur seal, A. pusillus pusillus
      • Australian fur seal, A. pusillus doriferus
    • Antarctic fur seal, A. gazella
    • Guadalupe fur seal, A. townsendi
    • Juan Fernández fur seal, A. philippii
    • Galápagos fur seal, A. galapagoensis
    • New Zealand fur seal (or southern fur seal), A. forsteri
    • Subantarctic fur seal, A. tropicalis
    • South American fur seal, A. australis
  • Genus Callorhinus
    • Northern fur seal, C. ursinus

• Subfamily Otariinae (sea lions)

  • Genus Eumetopias
    • Steller sea lion, E. jubatus
  • Genus Neophoca
    • Australian sea lion, N. cinerea
  • Genus Otaria
    • South American sea lion, O. flavescens
  • Genus Phocarctos
    • New Zealand sea lion (or Hooker's sea lion), P. hookeri
  • Genus Zalophus
    • California sea lion, Z. californianus
    • †Japanese sea lion, Z. japonicus – extinct (1970s)
    • Galápagos sea lion, Z. wollebaeki

Although the two subfamilies of otariids, the Otariinae (sea lions) and Arctocephalinae (fur seals), are still widely used, recent studies show they might not be correct as traditionally defined. Instead, they suggest three groups within the family; one with northern sea lions (Eumetopias and Zalophus), one with the northern fur seal (Callorhinus) and its extinct relatives, and the third with all the remaining Southern Hemisphere species.