by G. Lee

Created on: January 29, 2010

"Pinnipedia" means "fin or wing footed" and it is the name of the order that includes all seals. True to their name, these amphibious creatures have webbed flippers. They mate and give birth on land but feed at sea. These diverse and resilient animals can be found in various parts of the world like the icy waters of Antarctica and the Arctic Ocean as well as in South America, Africa, Australia and the Pacific.

There are three main types of seals - the walruses, the so-called "true" seals and the eared seals. The eared seals, so named for their small but visible ears, include the sea lions and fur seals. It is believed that they evolved from the same land ancestors that gave rise to the dogs and bears. Whilst lay people do not distinguish between the three families of Pinnipedia, they actually differ from one another. On land, true seals hunch a caterpillar-like fashion and use only their fishtail-like rear flippers for swimming. The eared seals on the other hand, use all four limbs for walking on land and use their front flippers for swimming. Walruses walk like eared seals but swim like true seals.

Seals give birth at specific areas and this is especially true of species that migrate long distances to mate. The female Northern fur seals seem to have an affinity with their own place of birth and usually deliver their pups within about ten yards of the same spot year after year. Female seals normally bear only one pup at a time, for the young must be large enough to survive the freezing oceans and feeding one large pup is more than they can manage.

Unlike dogs and cats, baby seals are not helpless at birth. Before they are even completely out of their mothers' birth canals, their eyes are wide open and their flippers are flailing about wildly. In fact, seal pups are able to swim on the very day of being born! They seem to be equipped with inherited behavior and instinctively know how to fend for themselves. As such, seals do not learn proper behavior. Seals are thus individualistic animals, which form no social bonds.

Seals are well equipped to swim in the deep oceans. Their large eyes give them sharp visions, which help them to see better underwater and to find food at great depths. Seals stop breathing when they dive. Hence, they store half of their required oxygen on a dive in the myoglobin, a protein that stores oxygen required for muscle function. Oxygen is conserved by stopping or slowing blood circulation to all but the critical organs. Skin loses heat

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