Cambrian: Opinion

’Tis the season for elephant seals’ ‘catastrophic molt’

Visitors to the Piedras Blancas elephant seal viewing site this time of year sometimes ask, “Where are the elephant seals?” They are looking for the large males with the trunk-like noses (the proboscis) and think that the smaller seals on the beach are a different type of seal. Most of the large males are on their way to Alaska, where they will forage in the Aleutian Islands, bulking up after fasting for more than three months while on the beaches here during the birthing and breeding season.

There are many elephant seals on the beaches now, but they are females and juveniles that have come in to shed their skin in what is called a catastrophic molt. Some of the young males, 5 or 6 years old, show the beginning growth of the proboscis, but at this point it is just a pointy or widening nose.

The adult males are not the only ones that have embarked on long journeys. This year’s weaned pups, called weaners, born from late December to early February, have set out on their first sea adventure. Where the weaners go when they leave the beach for the first time has been a mostly unanswered question, but new tracking methods are giving us clues. The data on their migration is limited because the tracking equipment is expensive and only about two-thirds of the males and one-half of the females survive their first journey.

However, in 2008 researchers at UC Santa Cruz tagged five female weaners before they headed out to sea. The tags, glued to the seals, were programmed to report for three months, and some continued longer.

Researchers, who had previously thought the youngsters’ first trips were shorter, were surprised to discover that at least two of the weaners made it to the Gulf of Alaska, and one went all the way to the Aleutians. They also discovered that weaners don’t dive as deep as adults on their maiden voyage, but they travel just as far as adults and spend the same amount of time at sea. It’s remarkable that a pup, nursed by her mother for less than a month, learns to swim and dive on her own, then swims to the Aleutian Islands and back, a round trip of more than 5,000 miles, continuously diving for food.

Meanwhile, back here on the beach, older females and juveniles are resting, fasting and looking rather tattered as they shed a layer of tan or brown skin and hair, ready to leave with a sleek new gray coat for another year at sea.

To learn more about the molt and elephant seal adaptations, attend a free exploratory lecture and rookery tour on May 4 or 11. The illustrated talk’s at Cavalier Plaza, 250 San Simeon Ave. in San Simeon, will begin at 10 a.m. (Doors open at 9:30 for coffee.) and last about 90 minutes. A tour of the rookery, conducted in small groups by docents, will begin 30 minutes later. For more information, call Friends of the Elephant Seal at 924-1628.

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