Mummified Seals

[This entry contains images of mummified seals]

Dec. 14, 2013

One of the more bizarre aspects of life in the Dry Valleys is the rare occasion on which you stumble upon a mummified seal when hiking in the mountains. Yup… a seal… a mummified one, at that… and in the mountains of a dry, barren landscape in Antarctica. The first time I saw one I was intrigued and took a few photos (at least I’d heard quite a bit about them before, since they’re an infamous enigma of the Dry Valleys), but now I’ve past so many more that it seems like just another quirk to the landscape here.

DSCN1487bMummified seal in the Asgard mountains

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Seals aren’t uncommon in Antarctica, but they live in the ocean and generally only make landfall for shorter periods, very close to the coast. What brought them 45 miles inland and up to elevations of 5900 feet above sea level is the mystery. Scientists generally believe that this may occur if a seal beaches on land and becomes lost, traveling inland instead of back to the coast, and scooting up and into the mountains, astray and disoriented. Since there are no organisms in the Dry Valleys larger than miniscule algae, there is nothing for the seals to eat when they travel this far inland, and some seals end up starving in this landscape. Luckily this doesn’t happen too often, as a recent study analyzed the carbon of crabeater seal skeletons in this region and found many to be hundreds up to 2,600 years old, which suggests that only one seal gets lost here every 8 years. Considering the millions of of crabeater seals that inhabit the coast surrounding Antarctica (estimates range from 7 to 75 million seals, since they’re very hard to track when they’re not on land), this seal-march into the mountains isn’t too frequent of an ordeal, but the evidence of their journeys remains for a very long time. The Dry Valleys are one of the driest places on Earth and the lack of moisture in the air mummifies the seals that do die here, preserving them for much longer than other climates where things would biodegrade.

Since I can’t approach too close to living wildlife in Antarctica, the mummified seals are interesting because it’s the only time I can get close enough to see what the teeth and skeletal shape of a crabeater seal really looks like. Crabeater seals live around the coast of Antarctica in such high numbers that they have the highest population of any seal in the world. Despite their name, crabeaters don’t actually eat crabs, but krill; very small, shrimp-like crustaceans in the ocean. While their jaws look menacing with rows of sharp teeth, crabeaters actually use their teeth to sift food by chasing schools of krill, opening their mouths wide to catch them, then spitting the water back out, trapping krill in their closed mouths like a built-in strainer. This is very similar to the way that baleen whales eat, and one of the reasons for the very high population of crabeaters in recent decades is the lack of competition for krill from blue whales, which also feed on krill but have been overfished in the last 100 years.

780px-Lobodon_carcinophaga_teeth.svgDrawing of crabeater teeth by Dimitri Torterat

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DSCN1529bAnother crabeater in the mountains

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DSCN1526b Crabeater on a saddle pass between Suess and Lacroix glaciers

In other news, it snowed the other day. This may not seem like a big deal considering the fact that I’m living in Antarctica, but it’s incredibly unusual for it to snow much in the Dry Valleys. This region gets an average of 5cm of snowfall per year, and hasn’t seen significant rain in over two million years. (It’s the DRY Valleys, after all.) Much of the snow that does form sublimates before it reaches the ground because of the powerful sunlight and dry conditions, so snow on the ground is less common. I was visiting another camp on the other side of Canada Glacier when the snow fell, and it was beautiful how quiet it made an already underpopulated and empty landscape.

DSCN1539Snow dusting on the solar panels

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DSCN1540 Snow up the valley towards Suess glacier

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This weekend we’re taking a helicopter into Wright Valley to measure flow at the Onyx river; the largest river in Antarctica. It’s only 16-20 miles long, but nevertheless, since most of Antarctica consists of a frozen ice sheet, this one wins the title for the largest on the continent. More than half of the streams are flowing at this point so the season is picking up quite a bit.

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Posted on 2013, in (Current) Season 3: Life in the Dry Valleys, 2013 (12/14) Mummified Seals. Bookmark the permalink. 1 Comment.

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