The Piedras Blancas beach is coming into its busiest season, the spring molt. Even more seals are on the beach in April and May than during the breeding season.
All adult females and the juveniles of both sexes return to the beach to molt their skin. That includes all 5,600 females who had pups during the past breeding season, and all the females who, for one reason or another, didn’t have a pup this year. About 100 fewer pups were born in 2017 than in 2016, but slightly more survived, 5,050. Despite the stormy winter weather, 90 percent of pups survived.
Elephant seals are unusual in experiencing a “catastrophic molt.” Other seals molt, but more gradually, so it isn’t so noticeable. Elephant seal skin peels off in sheets. It looks ragged, as if the seal had something wrong with it. The seals are OK. This is the normal way they get new skin once a year.
When they arrive on the beach, the new skin is already forming underneath the old skin. Within a few days, the old skin begins to peel off — first around body openings such as eyes and nose, and around scars. Bits and pieces float across the beach, but it doesn’t usually make its way up to the bluff. Friends of the Elephant Seals docents in their blue jackets have samples of skin to show visitors. Children especially enjoy handling it. Some adults recoil from it. Some say it feels more like Astroturf than the soft fur they anticipated.
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The old hair is tan and brown. The new skin being exposed is pearly gray. The new hairs that are just beginning to grow are transparent at first. As the new coat grows, the seals look smooth and sleek, except for any old scars. Those are permanent.
Adult males are not on the beach, but some subadults 5 and 6 years old are bellowing and sparring. Their noses are not fully grown, but different from the females, whose noses never develop that way. Adult bulls are off on their spring migration to the north, gaining weight lost during the 100-day fast of the breeding season. They will return in July and August, when they molt their skin.
Seals do not eat while they are on the beach. The females have been out in the ocean feeding for two or three months since they weaned their pups. They’ve regained some of the weight they had lost and are ready to start on next year’s pups. Females can gain two pounds a day when they are foraging at sea.
The females’ bodies begin to make the changes needed to have pups next season. The eggs fertilized at the end of the breeding season will now start developing into an embryos. After the females finish molting and return to the ocean, the embryos will implant in the uterine wall and begin normal development.
When they leave the beach after molting, they will remain at sea until they return to give birth next January.
Christine Heinrichs’ column appears the fourth Thursday of each month and is special to The Cambrian.