DIVE DRY WITH DR. BILL #405: IS IT A SEAL...ION?
This past weekend I attended the wedding of the son of very good friends. I've known the son and his twin sister since before they were born because I lived temporarily in their family's home when I returned to Catalina from Chicago in the early 80s. At the time, their mom was pregnant with the twins so I got to feel them kicking while still in the womb. I found a permanent place and moved out just before they were born, but spent much of their early years with these great "kids" as they grew up, playing with them at home and traveling into the interior. Hard to believe one of them got married before their "Uncle Boo." My years with them set the tone for this week's column (although in no way does it reflect on them or their parents!).
"Mommy, Daddy... look at the seal balancing the ball on its nose!" Sorry, kid... chances are if your mom and dad took you to the circus or to Seal, er I mean Sea, World or if you took the mighty Blanche W. down to "Seal" Rocks in the past, what you saw was NOT a seal. Yes, it's possible... but not very likely. OK Dr. Bill smarty pants (as opposed to Sponge Bob square pants), how can you tell? Well, young lads and lassies... because I'm an eminently trained marine biologist with decades of experience in telling the difference. But this week, I'll let you in on my secret clues so you can upstage your parents and teachers by correcting them. Don't worry, parents... this will not involve any sex education... I'm not qualified to teach it!
First, look at the head of the critter in front of you. No, not that girl whose pigtails you pull in class... the pinniped. That's a fancy schmantsy word scientists use to refer to seals, sea lions and their relative the walrus. It means "feather foot." However, you are supposed to be looking at the head, not the feet. Both seals and sea lions have ears. However, sea lions have external ear flaps that are easily seen while true seals do not. That's your first clue.
Okay, now you can look down at their feet. Seals do not have the ability to walk on land because their rear legs will not rotate beneath them to support their weight. Instead, they have to move like an inch worm on the beach... quite a trick for a male elephant seal that may weigh up to 4,500 pounds! The dainty harbor seal is a bit more graceful since individuals rarely weigh more than 250-350 pounds. Sea lions and other "eared seals" do have the ability to rotate their hindquarters forward and walk on all four feet... er, fins. When I get my first hip replacement, I'm going to ask for this feature. You can see this from the images of the California sea lion and harbor seal.
While we're into the podiatrist phase of this week's exploration, note the feet... er, fins... themselves next time you come face-to-face or fin-to-fin with a pinniped. The front flippers of sea lions are only partially covered with fur while those of the seal are more fully covered. If you took them into Island Wave for a pedicure, Lourdes' crew would immediately notice that the sea lion has long claws while those of the seal are shorter. Oops, I guess if they are doing the claws on the front flippers, the pinniped might be in for a manicure instead? Speaking of which. I had my first one from an absolutely gorgeous Vietnamese woman two months ago... but I digress (as usual).
Now if you happen to find yourself close enough to the face, be forewarned. The breath of both seals and sea lions smells... well, a little fishy. Your nose probably isn't sensitive enough to distinguish them that way. So take a deep breath, hold it and look into your pinniped's eyes. Oops, I meant that you should look closely at their whiskers, known technically as vibrissae. You can use whiskers if you prefer... I'll understand. Those of the sea lion are smooth while a seal's are beaded or crimped. Personally, I have never needed to get that close to tell the two groups apart, but if you insist... go ahead.
You may have already noticed a difference between the two on your very own. Sea lions tend to be sleeker and have longer necks. Seals tend to be... well, I know it isn't politically correct but face it... they're fat! I don't expect to see any of them at Jenny Craig's or Gold's Gym. They need the blubber to make them more attractive to great white sharks... er, I mean to keep them warm in the cold California winters. Heck, I do the same thing by adding a layer (or two) of "bioprene" during winter.
OK, let's get a little "deeper" into the differences (but not below "recreational depths" I hope). The "eared" seals belong to the group Otariidae while the "earless" or "true" seals are in the Phocidae. Don't worry, you won't be tested on that. Although both are in the Pinnipedia, some scientists believe they evolved from different lineages. "Eared seals" like our California sea lions may have arisen from a primitive bear- or dog-like creature, while "earless seals" like our harbor and elephant seal may have descended (literally, into the water!) from semi-terrestrial animals similar to otters. In that sense they are examples of convergent evolution where different species with different ancestors evolve to look and function in somewhat similar fashion. However, some scientists are now suggesting that both groups arose from similar ancestral stock. I'll await the DNA tests before I weigh in.
So now you know just about everything you need to so you can distinguish between seals and sea lions and make your parents and teachers proud... or a little embarrassed when you correct their mistake. Be gentle with them. They try very hard. I'm now editing video footage and writing narrations for a few new episodes about the marine mammals for my proposed new cable TV show, "Munching and Mating in the Macrocystis." As I continue to work on this, I'll offer up plenty of new tidbits about these interesting critters so you can impress that cute girl with the pigtails, or the boy with the great smile, in your school classroom. You can wow them with your knowledge. Hmm... come to think of it, that's never gotten Dr. Bill anywhere. Sigh.
Image caption: California sea lion and harbor seal showing hind flippers rotated in the former and extended behind the body in the latter; sea lion ear flaps and ear holes of the harbor seal.
This past weekend I attended the wedding of the son of very good friends. I've known the son and his twin sister since before they were born because I lived temporarily in their family's home when I returned to Catalina from Chicago in the early 80s. At the time, their mom was pregnant with the twins so I got to feel them kicking while still in the womb. I found a permanent place and moved out just before they were born, but spent much of their early years with these great "kids" as they grew up, playing with them at home and traveling into the interior. Hard to believe one of them got married before their "Uncle Boo." My years with them set the tone for this week's column (although in no way does it reflect on them or their parents!).
"Mommy, Daddy... look at the seal balancing the ball on its nose!" Sorry, kid... chances are if your mom and dad took you to the circus or to Seal, er I mean Sea, World or if you took the mighty Blanche W. down to "Seal" Rocks in the past, what you saw was NOT a seal. Yes, it's possible... but not very likely. OK Dr. Bill smarty pants (as opposed to Sponge Bob square pants), how can you tell? Well, young lads and lassies... because I'm an eminently trained marine biologist with decades of experience in telling the difference. But this week, I'll let you in on my secret clues so you can upstage your parents and teachers by correcting them. Don't worry, parents... this will not involve any sex education... I'm not qualified to teach it!
First, look at the head of the critter in front of you. No, not that girl whose pigtails you pull in class... the pinniped. That's a fancy schmantsy word scientists use to refer to seals, sea lions and their relative the walrus. It means "feather foot." However, you are supposed to be looking at the head, not the feet. Both seals and sea lions have ears. However, sea lions have external ear flaps that are easily seen while true seals do not. That's your first clue.
Okay, now you can look down at their feet. Seals do not have the ability to walk on land because their rear legs will not rotate beneath them to support their weight. Instead, they have to move like an inch worm on the beach... quite a trick for a male elephant seal that may weigh up to 4,500 pounds! The dainty harbor seal is a bit more graceful since individuals rarely weigh more than 250-350 pounds. Sea lions and other "eared seals" do have the ability to rotate their hindquarters forward and walk on all four feet... er, fins. When I get my first hip replacement, I'm going to ask for this feature. You can see this from the images of the California sea lion and harbor seal.
While we're into the podiatrist phase of this week's exploration, note the feet... er, fins... themselves next time you come face-to-face or fin-to-fin with a pinniped. The front flippers of sea lions are only partially covered with fur while those of the seal are more fully covered. If you took them into Island Wave for a pedicure, Lourdes' crew would immediately notice that the sea lion has long claws while those of the seal are shorter. Oops, I guess if they are doing the claws on the front flippers, the pinniped might be in for a manicure instead? Speaking of which. I had my first one from an absolutely gorgeous Vietnamese woman two months ago... but I digress (as usual).
Now if you happen to find yourself close enough to the face, be forewarned. The breath of both seals and sea lions smells... well, a little fishy. Your nose probably isn't sensitive enough to distinguish them that way. So take a deep breath, hold it and look into your pinniped's eyes. Oops, I meant that you should look closely at their whiskers, known technically as vibrissae. You can use whiskers if you prefer... I'll understand. Those of the sea lion are smooth while a seal's are beaded or crimped. Personally, I have never needed to get that close to tell the two groups apart, but if you insist... go ahead.
You may have already noticed a difference between the two on your very own. Sea lions tend to be sleeker and have longer necks. Seals tend to be... well, I know it isn't politically correct but face it... they're fat! I don't expect to see any of them at Jenny Craig's or Gold's Gym. They need the blubber to make them more attractive to great white sharks... er, I mean to keep them warm in the cold California winters. Heck, I do the same thing by adding a layer (or two) of "bioprene" during winter.
OK, let's get a little "deeper" into the differences (but not below "recreational depths" I hope). The "eared" seals belong to the group Otariidae while the "earless" or "true" seals are in the Phocidae. Don't worry, you won't be tested on that. Although both are in the Pinnipedia, some scientists believe they evolved from different lineages. "Eared seals" like our California sea lions may have arisen from a primitive bear- or dog-like creature, while "earless seals" like our harbor and elephant seal may have descended (literally, into the water!) from semi-terrestrial animals similar to otters. In that sense they are examples of convergent evolution where different species with different ancestors evolve to look and function in somewhat similar fashion. However, some scientists are now suggesting that both groups arose from similar ancestral stock. I'll await the DNA tests before I weigh in.
So now you know just about everything you need to so you can distinguish between seals and sea lions and make your parents and teachers proud... or a little embarrassed when you correct their mistake. Be gentle with them. They try very hard. I'm now editing video footage and writing narrations for a few new episodes about the marine mammals for my proposed new cable TV show, "Munching and Mating in the Macrocystis." As I continue to work on this, I'll offer up plenty of new tidbits about these interesting critters so you can impress that cute girl with the pigtails, or the boy with the great smile, in your school classroom. You can wow them with your knowledge. Hmm... come to think of it, that's never gotten Dr. Bill anywhere. Sigh.
Image caption: California sea lion and harbor seal showing hind flippers rotated in the former and extended behind the body in the latter; sea lion ear flaps and ear holes of the harbor seal.
