Cambrian: Opinion

Elephant seal birthing season starts early, thanks to king tides

An elephant seal pup on the beach in San Simeon near the Piedras Blancas lighthouse.
An elephant seal pup on the beach in San Simeon near the Piedras Blancas lighthouse.

The birthing season at the Piedras Blancas elephant seal viewing site got off to an early start this month, with the first pup born on Dec. 11, about a week earlier than usual, and pregnant females continue to arrive and deliver their pups.

The usually predictable pattern of “organization” on the beach prior to birthing was disrupted by the super-high king tides early in the month.

The wannabe alpha males began returning from their Alaska migrations in late November as usual and started vying for territory. During that period, the hierarchy is continually changing.

As one guy settles down on the beach, a bigger fellow with a bigger voice may make his entrance and take over. By the time the females begin arriving, there is some obvious division of space, with huge males separated from each other awaiting the pregnant females.

As the females arrive, each one looks for a safe place to deliver her pup, and settles near one of the males. At the peak of the season a male may have 30, 40 or more females in his harem.

The high tides messed up this familiar situation. The water came up so high on the beaches that the seals retreated from the beach and huddled together against the bluff on the north beach and far up into the dunes on the south beach. Males and females, young and mature, were mixed together, and there was no pattern developing until the tides subsided mid-month, and by then several pups had been born.

The problem with this confusion at that point in the season is that a mother and pup may not have the protection of an alpha male and may be harassed by younger males. If the high tides had hit in January, as they have in a few past years, newborn pups, not being able to swim, would have been lost.

Beaches used by the seals were back to a more normal situation in the days before Christmas, with alpha males entrenched in their territories and harems of mothers, pups and pregnant females forming as more females arrive. The territories remain in flux, however, as larger, more aggressive males arrive and challenge the reigning alphas.

The mother nurses her pup for about a month and goes into estrus, ready to mate with her alpha male and go to sea after fasting while birthing and nursing. The pup, which weighs 60 to 80 pounds when it’s born, can gain as much as 10 pounds a day on the rich milk, which can reach 60 percent fat content. The pup will need that reserve to live on while it hones its swimming and diving skills until it is seaworthy enough to head north in the sea and forage for itself.

The next two months are the most exciting and interesting times at the viewing site where we can observe the dramatic ups and downs of nature without disturbing its patterns.

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