18 February, 2002
SEALS, SEALS, SEALS! SEALS!
There are many marine mammals in the Antarctic coastal waters.
These are seals and whales. A few people have seen humpback seals near the
southern part of the safe boating area. People on the LM Gould saw Minke
and humpback whales while they were on the January cruise. We have seen
many seals near Palmer Station. In fact, we often have some seals sleeping
on the rocks right outside our lab door!
Seals are predators. They eat other animals in the Antarctic food web.
There are six species of seals that appear in the waters around Antarctica:
the leopard seal, the fur seal, the crabeater seal, the elephant seal, the
Weddell seal, and the Ross seal. We have had visits from the first four
species this summer at Palmer Station.
The leopard seal gets its name from its spotted coat. However, it has a
sleek head that looks more like the head of a snake! The leopard seal is
able to open its mouth to an amazing size! Male leopard seals can be 3
meters long and weigh 300 kg. Female leopard seals are larger, weighing 450
kg and 4 meters in length. Leopard seals eat penguins, fish, krill, and
other seals.
Leopard seals in the Palmer area have been known to bite the pointed ends of
Zodiacs when the boats are tied up at the dock. So, we have "leopard seal
protectors" at the ends of the Zodiacs! There have been cases where leopard
seals have attacked and bitten the bow of a Zodiac, causing it to partially
deflate! A leopard seal recently showed great interest in scientists diving
in the waters off Palmer Station. For that story, please visit the website
of the University of Alabama-Birmingham. Look for the story, "No Buddy of
Mine", by Charles Amsler, dated December 1, 2001.
http://wow.uab.edu/antarctica2001/
The Antarctic fur seal is classified in the family of sea lions and
walruses. We are told we can distinguish it from the "true seals" by its
external ears and its flippers. Adult males weigh an average of 200 kg, and
may be 2 meters long. Females are smaller: they weigh in at much less-55
kg. Antarctic fur seals move quickly on land, and they can be aggressive.
We are told to stay out of their way if we see one on land.
Antarctic fur seals have long hair and an undercoat of fur, as well. These
provide insulation. The fur seal does not have as much thick blubber as the
true seals. The fur seal used to be hunted for its coat, but hunting is not
allowed now. Fur seals eat krill, fish, and squid. Sometimes they eat
penguins.
The crabeater seal is the most numerous seal in the world. Crabeater seals
can be found on the pack ice. When the sea ice comes in to Arthur Harbor
and Palmer Station, we see many crabeater seals on the ice.
Crabeater seals eat krill; they do not eat crabs. These seals are slim and
fast in the water. Males may be 3 meters long, and weigh 225kg. Females
can be 2.7 meters in length., and weigh slightly more than the males.
The Southern elephant seal is the world's largest seal. Males can weigh
4000kg and grow to be 5 meters in length. Females can weigh 900 kg and grow
to be 3 meters long. They eat squid and fish, which they catch in deep
dives beneath the ocean surface. Elephant seals used to be hunted for their
body oil. Hunting is not allowed here now.
Male elephant seals fight to decide who will be the "beachmaster" or head of
a harem of females. We have seen young males practice this fighting. We
usually have a group of females on the rocks outside our lab building.
Sometimes I hear a noise that almost sounds like barking dogs. I know there
are no dogs here. When I go outside to check, it's the sound of the
females. It looks like they may be talking about space in the lounge!
Here's the math: change all these metric measure to the measurements of
length and weight that we use in the United States.
Here is a group of elephant seals. Photo courtesy of Donna Patterson.
This is a group of fur seals. Photo courtesy of Donna Patterson.
This is a leopard seal. It is following a Zodiac with what seems to be great interest or curiosity. Photo courtesy of Donna Patterson.
Near Elephant Rocks, two young bull elephant seals take each other on. Photo courtesy of Michele Cochran.
Look at that set of teeth! Photo of this leopard seal courtesy of Amy Chiuchiolo.
The female elephant seals often lie on this rocks outside our door. We call this area "The Lounge". Two seals were arguing over something--probably space!
Two young bull elephant seals try to see who will be dominant. Photo courtesy of Amy Chiuchiolo.
The argument continues in "The Lounge". These are elephant seals. They are moulting, so their skin looks patchy.
This image of a fur seal is courtesy of Amy Chiuchiolo. The fur seal is from the classification Otariidae, which includes sea lions and walruses. You can see why it is called the "eared" seal.
A group of crabeater seals rests on the ice. The elephant seals are in the foreground. This photo was taken just outside our lab building.
This fur seal showed some interest in us when we were on Humble Island. I wish you could see how fast this animal could move! In the background you can see the three blue survival cache barrels and some Adelie penguins.
These elephant seals on Humble Island didn't seem bothered to see us there. Access is restricted to this island, so the animals don't see many people. Here you can see the difference between the male elephant seal (toward the left) and the female on the right (with the hind flippers of other seals also visible!!)
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