Community Columns & Blogs

Elephant seals returning to Piedras Blancas this fall after annual migration

Students are returning to school, and young elephant seals are returning to the beach. It’s their “Fall Haul-Out.”

The juvenile seals straggle back to the beach one by one, in their own parade of sorts. The smallest are the young of the year, the pups that were born last winter, returning from their first migration. The rest are seals up to about 5 years old.

Young males work on their fighting skills, sparring with each other in the water and on land.

Mostly, they rest on the beach.

It’s another of the seals’ long annual fasts. They will spend about six weeks living off their blubber. The seals eat during the months they are at sea, then stop eating to take time out on land.

Elephant seals fasting on the beach metabolize their blubber to meet all their nutritional needs, including their need for water. But they need to use as little energy a possible when they aren’t eating. Elephant seals have physiological adaptations that conserve water, such as efficient kidneys and convoluted nasal passages that recapture moisture in their breath before they breathe it out. By conserving water, they conserve fat that would otherwise be metabolized.

More and more seals arrive, until thousands are on the beach during October. By then, the seals who arrived in August will be ready to return to the sea. One by one, they slip into the surf, until only the last stragglers are left when the bulls start arriving in late November.

The adult bulls feed along the continental shelf in Alaska in September. They’ll be at their blubbery best when they return for the breeding season. The pregnant females are far at sea, feeding to grow the pup that will be born in January.

Last winter’s pups left the beach in March and April. Without any leader to guide them, they swam away from the only home they knew. They may have traveled as far north as Alaska this first year, or may have only gotten as far north as Vancouver Island. All the ones on the beach have gone north and found their way back to the Central Coast.

Only about half of them will make it back.

Those that do are the successful survivors. They figured out how to hunt fish and squid. They may not be any bigger than the 200 pounds or so they were when their mothers weaned them, but they’ve survived their first migration. Any seal that makes it back to the beach has succeeded.

They can grow and gain weight next year.

Christine Heinrichs’ column on elephant seals is special to The Cambrian.
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