DIVE DRY WITH DR. BILL #573: THAT'S A LOT OF BLUBBER!
One of the sad things about many PhDs is that over the years they know more and more about less and less. Yes, many become highly knowledgeable specialists about a single species, sometimes even just a single facet of that critter's life like its mating strategy or digestive system or diseases. As an ecologist and evolutionary biologist, I've always tried to look at the bigger picture... how the individual pieces of the puzzle fit together in an ecosystem. Of course that renders me a generalist rather than a specialist, and there are many holes in my knowledge about the ocean and its inhabitants.
One of the biggest gaps in my understanding relates to marine mammals. I've never focused on whales, dolphins, porpoises, seals and sea lions. My marine biological icon, Edward F. "Doc" Ricketts of Steinbeck's Cannery Row fame, always eschewed (Gesundheit!) the "milk givers" of the sea. He was never partial to milk in the first place, much preferring a cold bottle of Bohemia instead! My limited contact with "milk givers" in the past involved trips to "Seal" Rocks with my students and a successful attempt to rehab a juvenile elephant seal in our school's dive locker back in the days before the Marine Mammal Protection Act of 1972 forbad such interactions.
About 1990 or 1991 I was assisting on a UCSB marine botany field trip to study the intertidal seaweeds on the north side of the Piedras Blancas lighthouse near Hearst Castle on Highway One. While students recorded their observations, I took a little walk around to the other side of the imposing lighthouse. As I turned the corner (of a round structure?), I came face-to-face with at least a dozen monstrous marine mammals! I had encountered the early arrivals from the newly founded northern elephant seal colony that first appeared there in 1990. I had no idea such a colony existed so it was a total shock and I quickly made my escape without even taking a single picture!
For many years I've thought about returning to Piedras Blancas to film the elephant seals. Back in the early 1990s I was a starving grad student at UCSB and couldn't afford such a trip (or diversion from my studies, of course!). From the middle 1990s to 2000, I was the dedicated vice president of the Catalina Conservancy and almost never took a vacation. Then when I left the Conservancy, I became a starving dive bum for another decade or so and once again couldn't spare the change (especially with rapidly rising price of gas and campground charges). Now that I'm semi-retired, I decided it was finally time to film these behemoths for future episodes of my cable TV show and write about them for you, my readers.
The northern elephant seal (Mirounga angustirostris) is the largest true seal in the northern hemisphere. True seals lack an external ear flap or pinna, unlike our California sea lions which are members of the "eared" seals. Of course both groups do have ears and can hear... otherwise why would they be so vocal? And if you think sea lions are loud, try spending a day at an elephant seal rookery! Elephant seals, also called sea elephants, received their common name both from their large size and for the dangling proboscis or nose extension of the male that looks somewhat like an elephant's trunk. The proboscis begins developing at 3-5 years and is fully formed by 7-9 years.
The male's "trunk" is not the only obvious difference between the boys and the girls in this seal species (and I'm not going into the obvious mammalian ones in this column). Males may be several times larger than the females. In researching this, I was astounded at the disparity in the numbers reported by various sources. I guess it is pretty difficult to get those seals up on a scale for an accurate weigh-in prior to their fights! I think it is safe to say that a typical bull can weigh 4,-5,000 and a few may top 8,000 pounds. Makes me feel like a 98 pound weakling. The girls are a bit more dainty at 900 to 1,500 with some in the 2,000 pound range. Average males are 12 to 14 feet in length with some stretching to 17 feet while the ladies are normally 6-10 feet with some exceeding that.
Juveniles and the girls have a round face with very large black eyes. Males have large canine teeth which are used to feed and in "turf wars" with one another. The fur is generally brown, tan or gray in color in the adult. They don't shed frequently like your dog or cat (but they still don't make good house pets!). Once a year the fur and upper layer of skin is completely sloughed off in a "catastrophic molt" which is accomplished on land.
Unlike sea lions, seals can not rotate their hind flippers and walk on them. They must resort to crawling on land like huge caterpillars. In part this is due to the fact they spend the majority of their lives out at sea and only a small part on dry land. Although these seals may be 50% blubber, and somewhat clumsy on land, they are excellent swimmers and divers. Their bodies are "streamlined" (well, for their size) and organs like the mammary glands and penis are internal. Swimming is accomplished using the rear flippers. The short fore flippers are not used much in swimming. They function primarily in scratching their itches and flipping sand over their bodies on land to cool off.
I actually made two trips to Piedras Blancas, one in December and one in January. As a result, I obtained nearly 10 hours of edited footage of these pinnipeds... enough to make a documentary about them that will be a sure cure for insomnia! MY research on the Internet has gathered enough information to write a few good columns for your reading pleasure. However, please don't read these columns or watch the resulting video while driving or operating heavy machinery! Stay tuned for the incredible history, migration and exciting sex life of these blubbery behemoths.
Image caption: Overview of colony at Piedras Blancas and two bulls fighting amongst large group of seals; female with pup and head of mature male with well-developed proboscis.
One of the sad things about many PhDs is that over the years they know more and more about less and less. Yes, many become highly knowledgeable specialists about a single species, sometimes even just a single facet of that critter's life like its mating strategy or digestive system or diseases. As an ecologist and evolutionary biologist, I've always tried to look at the bigger picture... how the individual pieces of the puzzle fit together in an ecosystem. Of course that renders me a generalist rather than a specialist, and there are many holes in my knowledge about the ocean and its inhabitants.
One of the biggest gaps in my understanding relates to marine mammals. I've never focused on whales, dolphins, porpoises, seals and sea lions. My marine biological icon, Edward F. "Doc" Ricketts of Steinbeck's Cannery Row fame, always eschewed (Gesundheit!) the "milk givers" of the sea. He was never partial to milk in the first place, much preferring a cold bottle of Bohemia instead! My limited contact with "milk givers" in the past involved trips to "Seal" Rocks with my students and a successful attempt to rehab a juvenile elephant seal in our school's dive locker back in the days before the Marine Mammal Protection Act of 1972 forbad such interactions.
About 1990 or 1991 I was assisting on a UCSB marine botany field trip to study the intertidal seaweeds on the north side of the Piedras Blancas lighthouse near Hearst Castle on Highway One. While students recorded their observations, I took a little walk around to the other side of the imposing lighthouse. As I turned the corner (of a round structure?), I came face-to-face with at least a dozen monstrous marine mammals! I had encountered the early arrivals from the newly founded northern elephant seal colony that first appeared there in 1990. I had no idea such a colony existed so it was a total shock and I quickly made my escape without even taking a single picture!
For many years I've thought about returning to Piedras Blancas to film the elephant seals. Back in the early 1990s I was a starving grad student at UCSB and couldn't afford such a trip (or diversion from my studies, of course!). From the middle 1990s to 2000, I was the dedicated vice president of the Catalina Conservancy and almost never took a vacation. Then when I left the Conservancy, I became a starving dive bum for another decade or so and once again couldn't spare the change (especially with rapidly rising price of gas and campground charges). Now that I'm semi-retired, I decided it was finally time to film these behemoths for future episodes of my cable TV show and write about them for you, my readers.
The northern elephant seal (Mirounga angustirostris) is the largest true seal in the northern hemisphere. True seals lack an external ear flap or pinna, unlike our California sea lions which are members of the "eared" seals. Of course both groups do have ears and can hear... otherwise why would they be so vocal? And if you think sea lions are loud, try spending a day at an elephant seal rookery! Elephant seals, also called sea elephants, received their common name both from their large size and for the dangling proboscis or nose extension of the male that looks somewhat like an elephant's trunk. The proboscis begins developing at 3-5 years and is fully formed by 7-9 years.
The male's "trunk" is not the only obvious difference between the boys and the girls in this seal species (and I'm not going into the obvious mammalian ones in this column). Males may be several times larger than the females. In researching this, I was astounded at the disparity in the numbers reported by various sources. I guess it is pretty difficult to get those seals up on a scale for an accurate weigh-in prior to their fights! I think it is safe to say that a typical bull can weigh 4,-5,000 and a few may top 8,000 pounds. Makes me feel like a 98 pound weakling. The girls are a bit more dainty at 900 to 1,500 with some in the 2,000 pound range. Average males are 12 to 14 feet in length with some stretching to 17 feet while the ladies are normally 6-10 feet with some exceeding that.
Juveniles and the girls have a round face with very large black eyes. Males have large canine teeth which are used to feed and in "turf wars" with one another. The fur is generally brown, tan or gray in color in the adult. They don't shed frequently like your dog or cat (but they still don't make good house pets!). Once a year the fur and upper layer of skin is completely sloughed off in a "catastrophic molt" which is accomplished on land.
Unlike sea lions, seals can not rotate their hind flippers and walk on them. They must resort to crawling on land like huge caterpillars. In part this is due to the fact they spend the majority of their lives out at sea and only a small part on dry land. Although these seals may be 50% blubber, and somewhat clumsy on land, they are excellent swimmers and divers. Their bodies are "streamlined" (well, for their size) and organs like the mammary glands and penis are internal. Swimming is accomplished using the rear flippers. The short fore flippers are not used much in swimming. They function primarily in scratching their itches and flipping sand over their bodies on land to cool off.
I actually made two trips to Piedras Blancas, one in December and one in January. As a result, I obtained nearly 10 hours of edited footage of these pinnipeds... enough to make a documentary about them that will be a sure cure for insomnia! MY research on the Internet has gathered enough information to write a few good columns for your reading pleasure. However, please don't read these columns or watch the resulting video while driving or operating heavy machinery! Stay tuned for the incredible history, migration and exciting sex life of these blubbery behemoths.
Image caption: Overview of colony at Piedras Blancas and two bulls fighting amongst large group of seals; female with pup and head of mature male with well-developed proboscis.
