ANTARCTICA IS THE COLDEST PLACE ON EARTH, WITH TEMPERATURES ON THE HIGH, DRY, POLAR PLATEAU SOMETIMES FALLING TO MINUS 90 DEGREES CELSIUS.
HERE, IT'S ONLY MICROBES THAT HAVE ADAPTED TO EXTREME COLD AND HUMANS WITH OUR POWERFUL TECHNOLOGY.
BUT ANTARCTICA'S SHORES AND OCEANS ARE RICH WITH CREATURES WHO HAVE EVOLVED THEIR OWN, UNIQUE WAYS OF SURVIVING IN THIS HARSH ENVIRONMENT.
WHALES AND SEALS ARE TWO SPECIES OF MAMMAL THAT ARE JUST AS WELL ADAPTED TO LIFE IN THESE COLD WATERS AS THE EMPEROR... AND ADELIE PENGUINS... THAT HAVE BECOME THE SYMBOL OF ANTARCTICA.
graphic set-up: SEAL SURVIVAL STRATEGIES
IN THIS VIDEO WE'LL SEE HOW DIFFERENT SEAL SPECIES MAKE THEIR LIVING ON AND UNDER THE ICE...
graphic: "THE SEALHEADS"
WE'LL MEET A TEAM OF RESEARCHERS FOR WHOM THE ANTARCTIC IS INSPIRATION AND ADVENTURE...
graphic: LEARNING TO BE A WEDDELL (WED-L)
...AND WE'LL LOOK CLOSE UP AT WEDDELL SEALS, AND SEE HOW THEIR PHYSIOLOGY AND BEHAVIOR FIT INTO THE ANTARCTIC ECOSYSTEM.
SIX SPECIES OF SEAL ARE FOUND IN THE WATERS AROUND ANTARCTICA.
THE 4 MOST COMMON SPECIES SHOW THERE ARE VARIETY OF BODY SIZES, HABITATS, DIETS AND SURVIVAL STRATEGIES THAT WORK.
chapter head: SEAL SURVIVAL STRATEGIES
THE LARGEST SPECIES, AS YOU MIGHT EXPECT FROM THE NAME, IS THE "ELEPHANT SEAL."
MALES CAN SOMETIMES REACH 7 METERS IN LENGTH, ABOUT 20 FEET, AND WEIGH UP TO 4 TONNES, AS MUCH AS A SMALL TRUCK.
FEMALES ARE SOMEWHAT SMALLER, WEIGHING UP TO ONE TONNE, AND GROWING TO ABOUT 3.5 METERS, 12 FEET.
ELEPHANT SEALS GET THEIR NAME FROM THEIR LONG, INFLATABLE PROBOSCIS, WHICH DOES INDEED LOOK RATHER LIKE A TRUNK.
IT SEEMS THESE PLAY A ROLE IN MATING BEHAVIOR!
THEY COME ASHORE ON THE ISLANDS CLOSE TO AMERICA'S PALMER STATION TO MOLT IN THE SOUTHERN SUMMER.
THEY ALSO RIVAL ELEPHANTS IN THEIR TRUMPETING, ESPECIALLY WHEN MALES ARE FIGHTING-WHETHER FOR REAL, OVER A FEMALE, OR IN PLAY-LIKE THESE 2 YOUNG BRUISERS.
ON LAND, THEY MAY LOOK CLUMSY, BUT UNDER THE ICE, WHERE THEY FEED ON FISH, SQUID AND KRILL, THEY ARE CHAMPION DIVERS AND SWIMMERS.
ELEPHANT SEALS HAVE MORE RED BLOOD CELLS-WHICH STORE AND TRANSPORT OXYGEN-THAN ANY OTHER ANIMAL, WHICH MAKES THEIR BLOOD VERY THICK, AND ALSO MORE HEMOGLOBIN PER CELL.
"LEOPARD" SEALS ALSO LIVE UP TO THEIR NAME, FOR THEY ARE THE FIERCEST SEAL SPECIES IN THE ANTARCTIC...
...SOMETIMES EVEN ATTACKING VISITING SCIENTISTS, WHOM THEY MISTAKE FOR LARGE AND PARTICULARLY JUICY PENGUINS, WHO'VE SOMEHOW DEVELOPED RED COATS!
THOUGH THEY ALSO EAT KRILL, GENUINE PENGUINS ARE, IN FACT, THE LEOPARD SEAL'S FAVORITE FOOD, AND THEY LURK AROUND COLONIES OF YOUNG BIRDS LIKE SHARKS ON THE PROWL.
THEY KILL PENGUINS BY GRABBING THEIR FLIPPERS, AND WHIPPING THEM BACK AND FORTH TO KILL AND SKIN THEM, BEFORE RIPPING THEM UP WITH SHARP TEETH!
THEY EVEN EAT SEAL PUPS FROM OTHER SPECIES, SUCH AS THE FUR SEAL.
MALE LEOPARD SEALS MAY GROW TO ABOUT 3 METERS, OR 10 FEET, IN LENGTH, AND WEIGH ABOUT 350 KILOGRAMS.
FUR SEALS ARE THE SMALLEST SPECIES FOUND IN THE ANTARCTIC, AND ARE, IN FACT, CLOSELY RELATED TO DOGS!
LIKE DOGS THEY HAVE TEETH AND WHISKERS, AND IT'S THEIR THICK FUR COATS WHICH KEEP THEM WARM, RATHER THAN MANY LAYERS OF FAT AS IN ELEPHANT SEALS.
BUT DON'T THINK OF THEM AS PETS! THEY'RE VERY FEROCIOUS, ESPECIALLY DURING THE BREEDING SEASON.
ONCE THE MOST ENDANGERED SPECIES WHEN HUNTED FOR THEIR FUR, THEY'RE NOW, LIKE ALL WILDLIFE IN ANTARCTICA, PROTECTED, AND THEIR NUMBERS ARE REBOUNDING.
PERHAPS THE MOST STUDIED OF ALL ANTARCTIC SEALS ARE THE WEDDELL. THIS SPECIES STAYS FARTHER SOUTH THAN ANY OTHER, VENTURING ONLY 15-20 KILOMETERS AWAY FROM THE CONTINENT.
EVEN DURING THE COLD, DARK WINTER, THEY STAY CLOSE BY, BELOW THE ICE, BREATHING THROUGH CRACKS.
ABOVE, TEMPERATURES PLUNGE TO MINUS 80... BUT IN THE OCEAN IT'S ALWAYS A RELATIVELY BALMY MINUS 1 TO 2 DEGREES CELSIUS.
THEN, COME ANTARCTIC SPRING, WEDDELL SEALS EMERGE, SOMETIMES GNAWING A HOLE THROUGH THE THICK ICE WITH THEIR TEETH IF NATURAL CRACKS AREN'T BIG ENOUGH!
THEY USUALLY RETURN TO THE SAME LOCATION YEAR AFTER YEAR, SEVERAL EXPECTANT MOTHERS, ONE MATURE MALE, AND SOON-LOTS OF NEW PUPS! THEY CAN LIVE FOR OVER 20 YEARS.
IN THIS SPECIES, FEMALES AND MALES ARE BOTH ABOUT THE SAME SIZE, 3 METERS, AND WEIGH ABOUT 400 KILOS.
chapter head: THE SEALHEADS
THIS WEDDELL COLONY AT BIG RAZORBACK ISLAND, ABOUT 2 HOURS AWAY FROM McMURDO STATION, HAS BEEN HERE FOR MANY YEARS... AND EACH YEAR A COLONY OF RESEARCH SCIENTISTS ALSO RETURNS.
Scientists around the breakfast table:
Researcher #1:
Would they take out a piece or would you just be left with a nice little set of teeth-marks?
OVER BREAKFAST THEY TELL TALES OF CLOSE ENCOUNTERS!
Jennifer Moss shows bruise on leg: These are teeth marks from a yearling, last year.
Researcher #1:
My God! Oh that isn't good.
Jennifer:
This is from the baby...
Researcher #1:
This is from a pup... Oh, no!
TEAM LEADER, MIKE CASTELLINI...
Michael Castellini:
We have to organize our life so that it's the same as the seals. The Weddell seals live a twelve hour day, they're pretty much up on the ice in the afternoons, sleeping so that we have access to them. So we sort of match our life to that, and our routine life is to go to bed around midnight or one o'clock in the morning and get up around eight or nine, have breakfast, so that we're ready to start working around noon, just about the time the seals are ready to quit their workday and come out on the ice and sleep.
Off camera voice:
Tania's gonna be the polar hero!
CASTELLINI AND HIS ENTHUSIASTIC YOUNG TEAM ARE LOOKING FOR CLUES ABOUT WHAT MAKES WEDDELLS THRIVE IN THE HARSHEST PLACE ON EARTH.
FOR TEACHER AND STUDENT ALIKE, THIS "UNIVERSITY OF THE ICE", IS A WONDERFUL PLACE TO LIVE AND WORK.
CASTELLINI ALSO STUDIES SEALS AND OTHER MARINE MAMMALS AT THE OTHER END OF THE EARTH, BACK HOME IN ALASKA.
Castellini:
We're trying to figure out which pups survive to become big seals, and which ones don't. And we are approaching that from the direction of how well they learn how to dive.
We're basically giving them a physical exam, much like you would go to the doctors'. And we ultimately can then figure out which ones make it and which ones don't. And then we correlate that with global patterns of food change, global patterns of where the ice is changing, and a variety of things that can affect which seals survive and which ones don't.
In fact we wrote the proposal to come here and work with these animals because the seals in the North that live in the Gulf of Alaska and the Bering Sea are in real trouble. Their numbers are going down, and we know the problem is at the pups. And the problem's with the young animals, and so we said let's go to the Antarctic where we know the animals very well from all the work that we've been doing, and the population is very stable, very healthy. And we can compare those two, and do a Pole-to-Pole comparison between the animals that live in the South and animals that live in the North, and see if we can figure out what's going wrong with the ones up North.
(continues over actuality)
The Weddell seal is extremely easy to handle. Most species in the world, we could not do this. The ability to work with a wild animal and a mother and pup just a few feet away from each other is essentially impossible in most other species.
Because they've never been approached by humans before, essentially, in their history, they don't have any predator on land, nothing bothers them on land, they think we're just big penguins essentially. So for us to temporarily move them around, we need lots of permits and lots of training to do it. We know how long we can keep a pup from its mom. We know how to keep them gentle. That's why when we're working with them, everybody's being very quiet except for when we're actually taking the measurements.
We have no evidence, ever, that after we have actually worked with an animal, that the mom doesn't want the pup back or anything. With these, they take them right back and it's very easily done, they can handle it quite easily.
THE PUPS MAY BE CUTE, BUT THEY'RE ALSO KINDA SQUIRMY. IT TAKES A FEW HUMANS TO HOLD THEM STILL... AND THEN SEND THEM ON THEIR WAY.
JUST AS IN ANY CENSUS, THERE'S A WHOLE LOT OF NOTE-TAKING.
BACK AT BASE THERE ARE SAMPLES TO CAREFULLY LABEL...
AND THE NEXT MEAL IS A TIME TO PLAN THE NEXT DAY'S WORK.
AND SINCE SEALS WON'T WALK ONTO A SCALE YOU HAVE TO BE INVENTIVE ABOUT HOW YOU CHECK THEIR WEIGHT.
chapter LEARNING TO BE A WEDDELL
Jennifer Moss:
"Can you pass me that tape measure?"
CASTELLINI AND TEAM ARE INTERESTED IN DISCOVERING HOW THE YOUNG SEALS LEARN THE BEHAVIORS THAT WILL SERVE THEM WELL AS ADULTS.
THEY'RE ESPECIALLY INTERESTED IN HOW THEY LEARN TO HOLD THEIR BREATH FOR LONG PERIODS WHILE DIVING...
Jennifer:
"Hips at 26"
name title:
Jennifer Moss, University of AK.
I'd like to understand how pups are able to compete with the adults, and how they dive and how they fit in their environment, and what their niche is as a marine mammal that's learning to be a marine mammal.
And work on this species and then some other species in other environments where they don't have such a stable sub-strate; this ice that we're standing on makes it very easy for them to learn they have a long period to learn. I'd like to compare it to other species in more temperate areas where the pups are born able to dive, and look at the relationships between the environment and their diving behavior.
DIFFERENT SEALS, DIFFERENT BEHAVIOR. THESE HAWAIIAN MONK SEALS ARE ADAPTED TO LIVE IN A MUCH WARMER OCEAN.
UNLIKE THE WEDDELLS, WHO HAVE SOME MONTHS OF LYING AROUND ON THE ICE WITH THEIR MOTHERS TO LEARN "PROPER SEAL BEHAVIOR", FOR THE MONKS IT'S SINK OR SWIM FROM BIRTH.
BUT, THEN, SINCE THE TROPICAL ENVIRONMENT IS LESS EXTREME, PERHAPS THEY NEED FEWER "LESSONS" IN ORDER TO SURVIVE.
SIDS graphic
CASTELLINI THINKS HOW WEDDELLS SAFELY HOLD THEIR BREATH MAY PROVIDE CLUES THAT WILL BE USEFUL IN UNDERSTANDING AND PREVENTING "SIDS"-SUDDEN INFANT DEATH SYNDROME.
(seal roar)
CASTELLINI
If you watch them carefully, when they sleep they hold their breath, and we found out that's a developmental process. Very young seal pups don't do that very well, very old ones do it extremely well, and the adults can hold their breath for ten or fifteen minutes at a shot while they're sleeping.
The work that we've been doing in relationship to SIDS, is following the development of that and how their body reacts to the fact that they're holding their breath while they're asleep. For them it's totally, completely normal. It's part of the whole process of learning how to become a seal and how to hold your breath.
So we're watching animals here develop away from what would be considered to be a human problem. And what it boils down to is we can work with a small mammal here just like a small human, except in this case these animals always wake up and they always breathe. And, of course, SIDS infants, that can be a problem for them.
(Castellini to camera, in front of a pup)
This Weddell seal pup back here is probably about four and a half or five weeks old. If you look carefully if it comes around from behind the mom, you'll see it still has a lot of its pup fur, but it's about half of its adult color, about half the fur looks like her. He's dropping his pup fur, and he's also very fat, and probably weighs close to a hundred kilos, or so, over two hundred pounds, and the mom is getting skinnier and skinnier as she nurses him longer and longer. He's just about ready to be weaned, probably in another five to ten days, this pup would be weaned.
When this pup is about a year old, if you came back next summer and were able to find him again, he would be a superb diver, capable of ten to fifteen minute dives very easily. And to the bottom of the ocean right here which is about 2,000 feet or so.
Eventually, by the time he'll get as old as his mom there, they are excellent divers, and can hold their breath in some cases for as long as ninety minutes, and they can gain two to three pounds a day at the time that they're nursing from their mom.
And the pup's getting bigger and bigger and in another ten days or so, he'll be completely on his own, ready to go.
FOR 3-4 MONTHS, THE "SEALHEADS" WILL LIVE OUT HERE AT BIG RAZORBACK, BRAVING WEATHER THAT'S SURE TO TURN VIOLENT AND WINDY BEFORE THE SEASON'S OVER.
THEY CAN'T JUST VISIT AND TAKE BLOOD SAMPLES BACK TO BASE. THEY HAVE TO DO SOME CRITICAL TESTS WHILE THE BLOOD IS FRESH IN ORDER TO STUDY HOW THE WEDDELLS' HEMOGLOBIN CAN BE SO EFFICIENT IN STORING THE OXYGEN THEY NEED FOR DEEP DIVING.
name title: Laurie Rea, University of Alaska
Seals in general have a very high volume of blood for their body size. They also have a higher hemoglobin concentration in that blood. So both of those things together allow the animal to carry more oxygen on board, in the body, when they're diving, thus they can "breath hold" longer. Without that, they wouldn't be able to dive to the depths that they need to forage to find the food that they're looking for.
TO BE A "SEALHEAD"-AS THE RESEARCHERS CALL THEMSELVES-YOU HAVE TO GET ALONG WITH OTHER HUMANS, IN CLOSE QUARTERS...
YOU HAVE TO LOVE THE OUTDOORS... AND TOLERATE OCCASIONAL HARDSHIPS... AND RESPECT THE SPECIES THAT YOU'RE STUDYING.
BUT IF THAT'S FOR YOU, YOU'RE IN THE BEST PLACE IN THE WORLD TO PURSUE YOUR DREAMS...
Jennifer Moss:
That we can get our hands on pups, repeatedly, is just... this are probably the only species you can do it on. And so it's just the perfect place for me to do the work that I want to do.
Castellini:
It's always been an adventure for me, I've been coming here for almost twenty years now. When you leave the Antarctic, it's as if it's a dream world. There's nothing back anywhere else that you can compare it too, and that's what really keeps us going.
Basically it's the science, because that's our job, but it's tremendously fun.
