Dive Dry with Dr. Bill

#433: That's a LOT of "Bull"

I was walking along our beach a short time ago, enjoying the day and the smell of the ocean when I noticed a sign on the seawall near the Wrigley Plaza stage. Given my aging eyes, and the fact I only had my reading glasses with me, I walked over to read it. "DO NOT DISTURB. Marine Mammal. Protected by Federal Statute." Being a curious marine biologist ("very curious" according to some of my friends), I peeked over the railing and there it was... a young northern elephant seal (Mirounga angustirostris).

I have been working on another episode of my cable TV show on pinnipeds, so I knew these seals had been "doing their thing" recently further north at places like Morro Bay, Point Piedras Blancas near San Simeon and Año Nuevo Island near Santa Cruz. Yes, I'm referring to the "other M word," mating (and giving birth to their pups, in the opposite order). These seals spend most of their lives at sea, but come ashore at a few select sites to pup and do their thing to create the next generation.

Northern elephant seals are the second largest seal in the world. The males or bulls may reach lengths of 14 feet and weigh 5,000 pounds (more than the combined weight of my two vehicles!). Females are a bit more dainty at a svelte 1,400 pounds and 11 feet. However, this pinniped is diminutive compared to its relative, the southern elephant seal (Mirounga leonina). Males of that species may be 20 feet long and weigh up to 8,800 pounds!

The fact that there are any of these elephant seals alive today is a minor miracle. Their huge size and bountiful blubber made them targets of seal hunters before the 20th century, since they could be rendered into lots of oil. Amazing how much damage the oil industry has done to whales and pinnipeds... not to mention the rest of the marine environment. Of course as long as I drive those two gas sipping vehicles, I'm part of the problem. By the end of the 1800s, this species was hunted very close to extinction. At the beginning of the 20th century, there may have been less than 20 individuals in the only surviving rookery on remote Guadalupe Island off Baja, Mexico.

From that tiny population, their numbers have increased to over 100,000 today and they have expanded their range thanks to early protection by the Mexican and U.S. governments. Elephant seals began to appear at the rookery on Año Nuevo in the 1950s. The growth of the rookery at Piedras Blancas south of Hearst Castle is even more spectacular. We visited that lighthouse site when I was a teaching assistant in marine botany at UCSB beginning in 1990. I took a walk to the other side of the lighthouse and was confronted by about a dozen male elephant seals. They weren't the ones that backed off! That was the first year these pinnipeds had appeared there. Currently, more seals come ashore to pup and breed at that site than at Año Nuevo.

Today this species ranges over a wide geographic area. They may feed from northern Baja to Vancouver Island, Canada with the males moving as far north as Alaska and the females, being much smarter, heading out to Hawaii. These seals feed mostly at night and at depths between 1,000 and 2,600 feet, on large squid, hake, sharks and rays. One was reported to have dived to nearly a mile and they may remain under water for over an hour. They must have some pretty serious technical diving certifications since I'll never go deeper than 200 feet.

Let's get back to the little fella all alone on Avalon's beach... by taking the usual round-about route I'm infamous for. The bull elephant seals first appear onshore at their rookeries in December and January. Like males everywhere, they fight for dominance with only a few winning the right to round up the babes and create harems ranging from 30 to 100. I have my hands full with one girlfriend! The females then arrive and give birth. The poor "little" pups (about 4 feet and 75 pounds) nurse for only a month and then are on their own. Once the pups are weaned, the girls are free to frolic with the harem bulls who may impregnate as many as 50 of them, and be responsible for 500 or more offspring during their lifetime. Think of the child support payments!

Here's where our youngster re-enters the picture. I'm guessing the little pup was a mere 2-3 months old, but that means it had already been cut off from its mother's fat-rich milk and was hunting on its own. Usually the young pups form their own groups. However there had been a storm with some pretty rough seas just prior to this one's appearance. I'm guessing it had been thrashed around quite a bit, and was pretty tired after the ordeal. It showed no sign of illness or starvation, so my hypothesis is that it was just resting and regaining its strength. Kind of like some of our island visitors after an extremely rough Channel crossing! By the next day it was off to sea again. I just wish some of the curious kids who checked it out had been a little more respectful of it and the warning sign.

© 2011 Dr. Bill Bushing. Watch the "Dive Dry with Dr. Bill" underwater videos on Catalina Cable TV channel 29, 10:00 AM weekdays and on Charter Communications Cable channel 33 at 7:30 PM on Tuesdays in the Riverside/Norco area. Please help me climb out of self-imposed poverty... buy my DVD's (see this link). Yes, take Dr. Bill home with you... we'll both be glad you did!

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Warning sign and juvenile elephant seal lounging on the beach near it; "are you my Dad?" and the youngster vocalizing.

This document maintained by Dr. Bill Bushing.
Material and images © 2011 Star Thrower Educational Multimedia