Otter

Seal

Scientific classification

Animalia – Chordata – Vertebrata – Mammalia – Carnivora – Mustelidae – Lutrinae

Animalia – Chordata – Vertebrata – Mammalia – Carnivora – Caniformia – Pinnipedia

Species

13 living species of semiaquatic or aquatic mammals

Pinnipeds, also known as fin-footed mammals are often generalized as seals. Pinnipeds include the walrus, eared seals, sea lions, fur seals and earless seals.

Characteristics

Otters have long, slim bodies and relatively short limbs, with webbed paws. Most have sharp claws on their feet, and all except the sea otter have long, muscular tails. They have very soft, insulated underfur, which is protected by an outer layer of long guard hair. This traps a layer of air, and keeps them dry and warm under water. They have very high metabolic rates to help keep them warm.

Pinnipeds are typically sleek-bodied and barrel-shaped. Their bodies are well adapted to the aquatic habitat where they spend most of their lives. Their limbs consist of short, wide, flat flippers. Fur seals have both blubber and a specially adapted fur coat, including outer guard hairs that repel water and a layer of insulating underfur. For this reason they were particularly prized by sealers. Many species were nearly hunted to extinction.

Diet

Fish and shellfish, and other invertebrates, amphibians, birds and small mammals. European otters must eat 15% of their body weight a day, and sea otters 20 to 25%, depending on the temperature.

Pinnipeds are carnivorous, eating fish, shellfish, squid, penguins, and other marine creatures. Some seals eat warm-blooded prey, including other seals.

Age

Up to 16 years

15 to 40 years depending on the species

Gestation

60 to 86 days

About 9 to 12 months depending on the species

Reproduction

The newborn pup is taken care of by the mother, the father, and all the other offspring. It lives with its family for about one year, so it can learn and be kept safe until maturity.

Males of some species aggressively defend groups of specific females, referred to as harems. Males of other species defend territories on reproductive rookeries while females move freely between them. After the female returns from her first feeding trip, the most important task for her is to find her own pup out of the mass of other pups. Feeding a different mother's pup is a significant waste of energy, as milk production has a high parental cost. The seal overcomes this complication by voice recognition. The mother and pup must learn each other's voices in the first few days after the pup is born, before the dam goes on her next hunt.

Lives

Most species live beside water, but river otters usually enter it only to hunt or travel, otherwise spending much of their time on land to avoid their fur becoming waterlogged. Sea otters are highly aquatic and live in the ocean for most of their lives.

Fur seals have both blubber and a specially adapted fur coat, including outer guard hairs that repel water and a layer of insulating underfur. For this reason they were particularly prized by sealers. Many species were nearly hunted to extinction.