Seals are mammals. All mammals breath air, have body hair and give birth to live young that are nourished with milk. Seals are found in all the oceans of the world with the highest distribution in Antarctica and the Arctic.
The California Sea Lion maybe the best known of all the seals. This is because it is the one most often trained to perform tricks or lives most successfully in zoos.
Seals and Walrus are in the group called Pinnipeds, meaning “fin-footed” mammals, but most people call the entire group Seals.
Fur Seals and Sea Lions are eared seals, also called “walking seals”, that have an external ear easily seen. They are better adapted for land as the rear flippers can turn forward making it easier to move on all fours when on land.
Earless seals, also called “true seals”, include Elephant, Weddell, Leopard, Crabeater, Harbor, Walrus and most other members of the true seal family.
All Seals have and/or are still-hunted commercially. In the past blubber was used for oil, fur/pelts for clothing, hide for leather and the flesh for food. Many species of Fur Seals were hunted to near extinction as both blubber and the special fur coat, outer guard hairs that repel water and an insulating underfur, had great commercial value.
Males are called “bulls” while the female is a “cow.” Newborns are “pups” and a group is a “herd” or “pod.” A female usually has one pup after a gestation of approximately 8 to 12 months. Many can live to be 40 or more years old while living along the coasts of most continents and the sea ice.
They are efficient swimmers and divers but clumsy while on land moving only their front flippers as their tail structure does not help with walking.
Most species molt once a year replacing worn fur. This keeps them on land and they risk hypothermia and drowning during this period of time. Pups are born with a natal coat of a different color and texture than adults. This coat is usually very thick to help keep them warm in cold environments or extra thin to keep them cool on summer sands. Their first molt is about 11 days after birth when they get their adult coat better suited for a life at sea.
Seal eyes are adaptable to above and below the surface of water. While swimming a clear membrane covers and protects the eyes. The nostrils close automatically when in the water and whiskers help to navigate. Seal skulls absorb sounds underwater that helps to communicate and navigate.
All Seals are carnivorous eating fish, shellfish, squid, krill and other marine creatures. Some specialize like Southern Elephant Seals and Ross Seals mainly feeding on squid. Crabeater Seals eat mostly krill and have special teeth to help with this. Walrus eat mollusk by sucking the soft parts from the shell. Leopard Seals, the most carnivorous and predatory seal, eats mostly penguins.
The Seal’s only predator is the orca, or killer whale, and larger sharks. In the Arctic they are a large part of the polar bear diet.