Natural History of Northern Elephant Seals

Seals and sea-lions find their food in the sea, but give birth and suckle their young on land. The northern elephant seal (Mirounga angustirostris) spends most of its life at sea, migrating vast distances across the northern Pacific. The adults return each winter to breeding-grounds along the eastern Pacific, including the Ano Nuevo State Reserve north of Santa Cruz, where they mate and give birth to the pups from the previous year's mating. Most of the impregnating is done by aggressive dominant males, who fight for the privilege of monopolizing the breeding. The new-borns put on a great deal of weight in a few weeks of suckling before being weaned and left to their own devices. Half of them do not survive their first trip to sea.

Northern elephant seal females and first-year juveniles relaxing on sandy beach near San Simeon, California.

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