Northern Elephant Seals

What are Elephant Seals? We are deep sea divers and long distance travelers. We fast for long periods of time while on land. Our food sources, skates and squids, small sharks and other seafood are so far away – thousands upon thousands of miles – that once we arrive on land, we have to wait a very long time before eating again.

Northern and Southern Elephant Seals

There are two types of elephant seals: the northern (found along the Pacific islands and coasts of Mexico and California); and the southern (found along the Atlantic islands and coasts of Patagonia, Chile, Tierra del Fuego, et al). This article is only about the Northern elephant seal.

Northern Elephant Seals

Northern elephant seals spend most of their time in the ocean, coming ashore twice each year, once to mate, breed and give birth, and the other time to molt (shed and grow new skin/fur). Between the molting and breeding seasons, the northern elephant seal is at sea for six to eight months, swimming, diving and feeding. Incredibly, they remain submerged for nearly ninety percent of their time in the ocean, surfacing a mere two to four minutes during dives.

Season Change at Ano Nuevo

Now that the breeding/mating/birthing season is over, so too are the guided hikes at Ano Nuevo. That means pretty soon we will be entering the roving season. This is when the public can access areas that up to two weeks ago, were only accessible by guided hikes (led by volunteer naturalists like me). The roving season will be less hectic, more laid back and so, I am hoping to do some sketching and painting while volunteering out by the coast.

Breeding Season

During the breeding season (December to March), many of the adult males (the alphas, for sure) are on the beach for about 100 days without food. The mature females are on land for about five weeks. The females who are coming in pregnant during the breeding season give birth within 4-5 days of arrival. They nurse their pup for about 24-28 days, mate during the last 3-5 days of nursing and then head back into the ocean to find food to eat.

Elephant Seal Pups

Elephant seal pups weigh about 70 pounds at birth. They quadruple their birth weight while nursing, but lose about 1/3 of that weight during the weaning period.  The common belief is that the mom weans her pup, leaves it all alone and it then has to figure out how to survive. The mom in me thinks this cannot be! Momma elephant seal, while nursing her baby is saying things, teaching him/her how to survive and us dumb humans don’t even realize it. That is what I think. I watch mom and pup bonding during those 28 days before weaning occurs and I imagine mom passing on the following tidbits: “Baby, you see that far side of the island over there? Don’t stray there, my love. There are these pretty white sharks who are just waiting to greet and eat my plump little baby. Steer clear my love. Swim in the open. Swim toward the deep my love. Head in that direction over there. If you pay attention to what I’m saying, you’ll be just fine. Good luck my baby. I love you.” That is what I think the mom is telling her baby all the while that she is nursing him or her.

Incredible Divers and Swimmers

Elephant seals dive as deep as 2,000 t o 5,000 feet for food. The average dive lasts about 20 minutes, but they can dive for an hour or more. They resurface for 2-4 minutes and continue this diving pattern 24 hours a day! The females eat mostly squid; the males eat small sharks, rays and bottom-dwelling fish.

The male elephant seals from Ano Nuevo typically travel 5,000 miles round trip, towards the Aleutians where they feed along the Continental Shelf. They make this trip twice per year. The female elephant seal travels a shorter distance, about 3,000 miles along the Northeast Pacific, in the direction of Hawaii. She too, makes this trip twice per year.

Remarkable Comeback

The northern elephant seal was hunted to near extinction for their blubber. By the early 19o0s, only a small group of between 20-100 managed to survive the hunts. Protected first by Mexico (where this small group was found) and later by the United States (as they multiplied and expanded their range), the elephant seals have managed to multiply and increase their population. Today’s population is estimated to be around 175,000 to 185,000 seals. All of them are from the bottleneck, the same gene pool, that was discovered on Guadalupe Island, Mexico, a little over 100 years ago. Researchers at the nearby University of California, Santa Cruz (UCSC), are tracking and building a database on the movement and habits of the Ano Nuevo population of elephant seals. With each year comes new revelations. For a brief overview of the work being done on elephant seals by the UCSC, visit their site at http://news.ucsc.edu/2012/05/elephant-seals.html.

Interesting Facts

The adult females can weigh up to around 1,700 pounds and the males, up to around 5,000 pounds. The mature male has a bulbous appendage for a nose. It is called a proboscis. He uses it to honk and to assert dominance. For more interesting facts about the northern elephant seal, visit the National Marine Mammal Laboratory’s site at:

http://www.afsc.noaa.gov/nmml/education/pinnipeds/nelephant.php

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About the Photographs

Photo credit for the male juvenile elephant seal at the top of the post belongs to The Marine Mammal Center. You can see his proboscis is just barely starting to form. Only the males of the specie grow this nose and it seems to serve no other purpose except for asserting dominance, which is crucial in the breeding season. (Not all males get a chance to mate.)

I took the second photograph of a colony of what is mostly young pups, at Ano Nuevo State Park, two weeks ago. The seals in this photograph will be heading out to the ocean soon. They will have many challenges along the way, including figuring out where to go, what to eat, and how to avoid predators like the great white sharks that lay in wait not too far from where they are now. The mortality rate for young elephant seals is extremely high. Only about twenty six percent of them make it to age two. Some of the young die at the rookery but the majority of deaths occur at sea. For more details on elephant seals’ mortality rate, see the UCS”s 1971-78 Ano Nuevo study at:

http://neophoca.ucsc.edu/leboeuf/pdfs/Eseals.1994.LeBoeufMorris.7.pdf

No wonder then, that once a female is mature enough to have a pup, she continues to have one every year, for the rest of her life.

The old guy below is an alpha male. He has been in many a battle as is evident from the scarring on his chest shield. This photo is the property of Marinebio.org.