Eared seal

Eared seals, also called otariids or otaries, are a group of marine mammals. They include sea lions and fur seals. They belong to the family Otariidae, one of three families of pinnipeds. Pinnipeds are animals that live in water and on land. There are 15 living species of eared seals. 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. This is why they are called eared seals. Their name comes from the Ancient Greek word for "little ear." These animals spend much of their time in the water hunting for food. They also 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, and then spread to 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, dating to the middle Pliocene.

Traditionally, otariids were divided into two groups: fur seals (Arctocephalinae) and sea lions (Otariinae). But recent studies of the genetic evidence show that some groupings may be more closely related than we thought. Because of this, the family Otariidae is now split into seven genera with 16 species and two subspecies. Fur seals are usually smaller, show more sexual dimorphism, eat smaller prey, and travel farther when looking for food than sea lions.

Anatomy

Eared seals, also called otariids, have small ear flaps you can see. They have bigger front flippers and stronger chest muscles than true seals. They can turn their back legs forward to walk on all fours, which helps them move easily on land.

Though they spend less time in water than true seals, eared seals can swim very fast and turn quickly using their flippers. They look a bit like dogs with sharp teeth and visible ears. Male eared seals can be much larger than females, from the smaller Galápagos fur seal to the very large Steller sea lion.

Behavior

Eared seals, also called sea lions and fur seals, have special ways to live and care for their babies. They often meet on beaches or rocky places, usually on islands, to have their babies at certain times of the year. Most of these seals choose one male to stay with many females during this time. The males might show off or make loud sounds to claim their area. The females usually come a little before they have their babies.

These seals eat fish, squid, and krill. Some stay near the shore to catch bigger fish, while others swim farther 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. 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.