Cambrian: Opinion

Juvenile elephant seals return to Piedras Blancas after months at sea

Plenty of seals are on the beach at Piedras Blancas right now. Not the giant adults, but some hefty aspiring bulls and plenty of younger seals. The “Juvenile Fall Haul-Out” continues into November.

Young seals of both sexes arrive to take a six-week rest on the beach. Most are less than 5 years old, although a few 6-year-old males were on the beach in mid-October. A major feeding event drew many dolphins, lots of pelicans, cormorants and gulls, and a few humpback whales to Piedras Blancas. The water boiled with activity. Every day brings different critters to the area, which is protected as part of the Monterey Bay National Marine Sanctuary.

The elephant seals, which don’t eat in this area, were unimpressed.

The pups born last January return to the beach for the first time. They have had to master navigation, diving and hunting skills. Their only guide is whatever instincts they’re born with.

They’ve spent the past months, since they left the beach in March and April, diving deep below the surface, hunting for fish and squid. The seals hunt at 1,000 feet and deeper, below thousands of feet of lightless, cold water.

Even these first-year pups, called the Young of the Year, dive as deep as 4,000 feet. With no guidance, they found the northern feeding grounds along Canada’s west coast, perhaps as far north as the Aleutians, where the adult males feed. Returning to Piedras Blancas, they make forward progress on their dives. Breathe for two or three minutes, take a final breath, breathe out, dive, float down, hunt, turn around and swim back up to the surface to breathe. Twenty minutes, half an hour, 2,000 feet, 3,000 feet, always moving forward.

Half of the Young of the Year won’t make it back. Those that do may not weigh any more than they did when they left. Surviving is victory enough.

The seals have short, stubbly fur. It looks nearly black while it’s still wet. As the sun dries it, it takes on a lighter brown color.

The young seals may surf a wave onto the beach. You may see a seal rolled onto its side, showing a light belly. It’s called countershading, the dark back and light underside. It’s a typical ocean camouflage, to help protect them from predators. Great white sharks and orcas, also countershaded against their own predators, see their dark backs when they are swimming above them, blending into the ocean depths. Ocean predators swimming below them see the light belly against the bright surface. In the ever-changing play of light and dark, any advantage helps.

They don’t eat while they are on the beach. They meet all their needs from metabolizing their blubber. They don’t drink at any time — what would they drink, in the ocean? Their large kidneys filter salt from the prey they eat and maintain their normal tissue balance.

Young males engage each other in battle, but it’s not serious fighting among this age group. It’s practice for adulthood and, along with just being out of the water, a way to strengthen their bones. Visitors often remark on how much the tussling reminds them of their own teenage boys.

The juvenile elephant seals take the rest they need in the fall, before their elders begin to arrive in December for the breeding season.

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