John Ugoretz

John Ugoretz, US Navy biologist on San Nicolas Island
John Ugoretz

Chapter 13

John Ugoretz, US Navy biologist on San Nicolas Island, discusses the elephant seals’ physical characteristics and behavior during different times of the year.

Northern elephant seals live in Pacific Ocean coastal areas. Adult male elephant seals can weigh as much as 5,000 pounds and are 14–15 feet long. The elephant seal is named for the large overhanging nose of adult males, which looks similar to an elephant’s trunk. The females are smaller in comparison, weighing about 2,000 pounds and growing to about 10 feet in length. Elephant seal fur ranges from silvery grey in pups to dark brown in adults.

Elephant seals swim from San Nicolas northward into the Gulf of Alaska two times each year in what is called a “double migration.” Elephant seals make their first annual migration to breed and rear pups. The breeding season begins in December when the first males arrive on San Nicolas. The huge males engage in violent battles to establish dominance. The successful males do most of the breeding. Adult males are usually covered in scars on their necks and chests from these ritual mating battles.

In late December, the females begin to arrive and form “harems” on the beaches. About five days after arriving, females give birth to the pups that were conceived the previous year. The elephant seal pups, which are born weighing about 70 pounds, grow to 250–350 pounds in less than a month after feeding on their mothers’ rich milk. By March, most of the adult elephant seals have departed, leaving the weaned pups on the beach. The pups depart in mid to late April.

Elephant seals return to San Nicolas Island on their second migration to shed their fur. While most mammals shed their fur year round in small amounts, elephant seals “molt” or lose all of their fur and their outermost skin layer at once.

Molting elephant seals look shaggy and people often incorrectly assume the seals are sick. It takes about four weeks for the seals to molt completely and grow a new coat. Male and female elephant seals return to molt at different times of the year.

During these two migrations male elephant seals travel at least 13,000 miles and spend 250 days at sea each year. Females travel at least 11,000 miles and spend 300 days at sea.

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Last updated: November 26, 2017