Northern Elephant Seals

Two of California’s coastal state parks host large, strange-looking creatures each winter. Both Año Nuevo State Park and Hearst San Simeon State Park serve as breeding grounds for northern elephant seals (Mirounga angustirostris).

Named for their large size and the male’s long, pendulous nose, elephant seals were slaughtered in the 1800s for the lamp oil that could be rendered from their blubber.

By 1892, fewer than 200 of these seals existed, living on the remote island of Guadalupe off the coast of Baja California. In 1922 the Mexican government gave protected status to the elephant seals, and the United States followed suit a few years later when the seals began to appear off the southern California coast.

Elephant seals began breeding and birthing on Año Nuevo Island in 1955. The birth rates increased steadily, and a colony began to thrive. Males began to haul out on the mainland in 1965. A pup born in January 1975 was the first known mainland birth of a northern elephant seal at Año Nuevo; 86 pups were born there in 1978. The number of seals breeding and giving birth on the mainland is still increasing, as it is at Hearst San Simeon State Park. Volunteer docents lead tours that will not disturb the breeding and birthing processes.

Elephant seals spend most of their lives up to 5,000 miles out from the mainland at sea, coming ashore only to molt, give birth and mate. Breeding takes place from December through March.

The first males arrive on the beaches in December. Weighing close to 2½ tons, huge bulls engage in violent battles to establish dominance. Battles for dominance between bulls are among the bloodiest of any species. The successful bulls do much of the breeding; most of the responsibility falls on the “alpha bull” who tops the social ladder.

In early December, 800- to 1,600-pound females begin to arrive and form “harems” on the beaches. Three to six days later, the females give birth to the pups conceived the previous year. Each female bears one pup and nurses it for about a month. Feeding on its mother’s rich milk (up to 55% fat), the pup grows from about 75 pounds at birth to 250-300 pounds in less than a month.

Before returning to the ocean, females may mate several times—after they have abruptly weaned their pups by deserting them. By mid-March, most of the adult seals are gone, leaving the pups behind.

The weaner pups then molt their original black fur, which is replaced by a shiny new silver coat. Soon they begin learning to swim in the shallow offshore waters. When they mature, these seals will be able to dive up to 5,000 feet to forage for bottom-dwelling marine animals such as squid, eels and rockfish. In late April, they begin to head northward in the Pacific Ocean to look for food.

Between April and November, adult elephant seals return to the beaches in smaller numbers (based on their age and sex) to molt. This “catastrophic” molt takes about a month for the seal to shed its outer skin layer, fur and whiskers.