Saturday, February 22, 2014

Saturday Short Subjects: The Seals of Año Nuevo

Those are not boulders strewn on the sand, no remnants of geologic upheaval. Those dark mounds are living, breathing mammals — northern elephant seals (Mirounga angustirostris). They have either traveled 6000 miles to return to this particular spot on the California coast, or they are newly born on the beach at Año Nuevo State Park. They earned their name because adult males have large noses that resemble an elephant’s trunk.

Elephant seals, prized for the fine oil that could be rendered from their blubber, were hunted to near extinction. By 1910, it is estimated that there were fewer than 100 individuals, living off the coast of Baja California in Mexico. In 1922, the Mexican government granted the seals protected status, and when they began to appear off the southern California coast, the US government did the same.  Today the population is approximately 150,000 (124,000 in California). Their recovery is a dramatic example of how a species granted protected status can rise again. Elephant seals began their return to Año Nuevo, on the mid California Coast, in the mid-1950s.

A bull rising to the challenge.

The males arrive in early December to establish their territory. Bull elephant seals, weighing up to 4500 pounds, engage in fierce combat to establish dominance.

By mid-month, the females, who weigh 800 to 1600 pounds, begin to arrive, clustering in “harems” on the beach. They give birth and nurse their offspring (always just one) for four weeks. The females do not eat during this time. After a month, the emaciated moms return to the sea, but not before they mate, perhaps several times! 

By mid-March most of the adult seals migrate north to waters off the Alaskan coast, a journey of 6000 miles, to eat and recuperate. There they live well offshore and often dive nearly a mile below the ocean surface in their hunt for food.  

Two weaners are in the foreground.
They leave behind the “weaners” who must learn to fend for themselves on their own. By the end of April, the weaners, too, depart for Arctic waters.

Smaller numbers of female and juvenile seals return to Año Nuevo for four to six weeks between April and August for summer molting, after which they return to the Arctic. The only time elephant seals return to land is to molt, to give birth, and to mate. Seals born at Año Nuevo return to Año Nuevo. 

To visit Año Nuevo between the months of December and March, one must make a reservation and walk with a guide. This is for your protection as well as the seal’s. With male elephant seals weighing over two tons, you don’t want to get in the way of a challenge! The Año Nuevo website advises: Seals can sometimes appear dead due to their quiet nature of sleeping on beaches. However, the majority of the time they are very much alive. Never get within 25 feet of an elephant seal. 

More weaners with Fred on the right.
Our guide was Fred, a retiree from Apple, who had accumulated an incredible horde of  information on the seals during his seven years as a volunteer naturalist; he even had a self-published book of seal facts and images to share! Here are some of the amazing things we learned from Fred on our tour:
  • Only about 4% of male elephant seals ever get to mate
  • Those who do rise to alpha male mate for only one season and have a harem of 50-70 females.
  • After the female mates (on her way back to the sea), cell division begins, a blastocyst is formed, but the embryo does not implant until the female is out at sea and has recovered some of her body weight!

We witnessed and heard (males make a loud drumming sound to warn lesser males to stay away) a couple of male challenges, but no real fights.  We saw a few newborn pups with their moms and lots of “weaners” (pups over a month old) trying to figure out life on their own. Not all of them will make it; the staff at Año Nuevo does not intervene. 

Researchers, however, have begun to equip some of the moms and babies with cameras and tracking devices so they can learn more about their mysterious time at sea — where they go, how they rest, how they journey so far.

For our long hike over the dunes to the beach of Año Nuevo on January 31, it was windy, but warm enough to wear just a light jacket. Seals like to cool off by flinging sand onto themselves with their flippers when they get too warm. There was a whole lot of sand flinging going on that day.

For more on the Northern Elephant Seal, visit the Año Nuevo State Park site and the Marine Mammal Center site, where you can even hear the distinctive sounds of the adults and weaners.

The cliffs you see were created by tectonic activity.
Año Nuevo is part of the Monterey Formation.
What a wonderful memory to carry us through the mostly miserable weather we’ve been having in the East since our return. Today we did, however, have an entire day of sun, blue skies, and warm temperatures — at last!

Enjoy your weekend, wherever you are and whatever your weather.

Why Saturday Short Subjects? Some readers may recall  being dropped at the movie theater for the Saturday matinee — two action-packed feature films with a series of short subjects (cartoons or short movies, sometimes a serial cliffhanger) sandwiched in between. Often the short subjects were the most memorable, and enjoyable, part of the morning. That explains the name. The reason behind these particular posts is that we are all short on time. My Short Subject posts should not take me as long to write or you as long to read (or try).

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