Cambrian: Opinion

The big ‘beachmaster’ bulls are returning to elephant seal rookery at Piedras Blancas

The big, blubbery elephant seal bulls have started arriving at Piedras Blancas since late November. Their deep trumpeting will echo across the beach.

It’s been peaceful as the remnants of juveniles, still resting from their fall haul-out, remained sleeping on the sand. A few tussle with each other in the water. But they’ve abandoned the beach to their bigger brothers, to migrate north, bulking up, to take their place some day on the breeding beach.

The young seals, mostly males, don’t eat while they are on the beach. Their bodies are adapting to long fasts. As adult bulls, they will spend as long as 100 days during the breeding season without food.

The bulls are returning to California from their northern feeding grounds. Bulls forage along the continental shelf in Canada and Alaska. They eat fish such as shark, flatfish, ratfish, hagfish, as well as crab, squid and octopus.

The size of the nose (technically, proboscis) is a rough indicator of seal age for males. The females don’t grow one, keeping a more dog-like face. It starts growing when the young males are about 5 years old, bending down. It grows into a noticeable trunk in the following year. It continues growing throughout the seal’s life. Look for longer noses on adult bulls.

Along with the nose, they develop a “chest shield,” thick calloused skin, actually keratinized with the same material that forms our hair and nails. They rip and tear at it when they fight, but it protects them from life-threatening injuries. Look for pink, crinkled skin.

November was the calm before the storm of the birthing and breeding season. Bigger, older, more experienced bulls soon stake their claims on the beach. The most dominant males do most of the breeding, so there’s a lot at stake. Every male wants to be a beachmaster.

One visitor approached me in distress: “They’re dead! I came all this way to see a seal, and they’re dead!”

Not to worry. Even if they don’t often breathe, they aren’t dead. As deep divers, to 2,000 feet and deeper, they breathe only every 20 or 30 minutes, and sometimes even longer. One seal was timed at almost two hours.

On land, they may breathe only that often. Breathing means losing moisture, which the seals generate by metabolizing their blubber. Since they aren’t eating and living off their blubber, conserving every drop counts.

The seals have a special structure inside their skulls to capture moisture on their breath before it escapes. And infrequent breathing helps, too.

Bulls challenge each other for dominance. Most interactions are resolved simply: One challenges another, they take each other’s measure, and one retreats. About 20 percent of challenges lead to actual fighting.

Dominant beachmasters have to stay on the beach to defend the harem of females with whom they will eventually mate, after their pups are weaned. Less dominant bulls are always ready to challenge the beachmaster. They aren’t above sneaking into the harem, either.

All’s fair in love and war for elephant seals.

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