Forget the siren’s call. I have heard the seal’s burp.
Last night was my “most fav’ritest” night, as Sam Gamgee might say, since arriving in Antarctica… because it was the first official SCIENCE SUNDAY of the season!
Throughout the summer, or “mainbody,” different scientists do presentations for the McMurdo community on their research. During WinFly, instead of live scientists, they showed episodes of the BBC’s Life series. It’s amazing but, quite frankly, not the same as a real live scientist standing in front of you and talking about the ionosphere and whatnot.
Last night, the only group of scientists currently doing research (most will arrive in the coming weeks) put on a presentation that BLEW MY MIND. They are tracking Weddell Seals, big, torpedo-shaped lummocks that quite frankly make manatees look svelte. And they’re not just tracking them… they are capturing them and outfitting them with all kinds of stuff.
Wait. Before I go on, I must note that they have been doing this for years and claim to have the animal’s comfort and safety as a high priority. Their gadgets, which I will detail in a moment, are attached to neoprene pads that are then glued to the seal’s fur, so it’s not invasive and the seal still has full range of motion. When they recapture the seal, they remove the gadgets but leave the neoprene. In December, the seal molts and sheds its coat, the neoprene and any sign that, for a few weeks in spring, it looked like RoboSeal.
So… what do they attach? A camera for starters, with infrared light that neither the seal nor its prey sees but that allows the (human) viewer to see the hunt from the seal’s point of view. There is a microphone. There is an accelerometer that records each hind limb stroke. There is GPS and a time-depth sensor and a bunch of other stuff that I don’t even remember because I was too blown away by the footage of a seal catching fish that it found under sea ice in near darkness.
These particular scientists are trying to figure out how Weddell seals hunt in the polar winter. All the bells and whistles they stick on the seals allow them to create 3D dive profiles so they can track not only how fast and deep the seal was swimming, but its hunting patterns, when it caught fish, when it didn’t, how it accelerated, how long it stayed under the water and so on.
The sample dive profiles they showed detailed the seal’s speed and number/intensity of stroking for every second, as well as where and when it caught a fish. It was fascinating to see how the seals glided down to depths of 100-400 meters (330-1300 feet, more or less) then did a series of wave-like rises and falls, often catching a fish at the peak of a wave, suggesting to me they hit their prey from below, just like Great White Sharks.
The big question is how the seals are locating their prey at all… they have excellent low-light vision but in the conditions of a polar winter, even that’s not worth much. Curiously, there are also some blind seals that apparently do just fine in the wild (though none have been part of this study), hunting and feeding on their own. And it’s clear from the SealCam videos they showed that the seals are not just hanging around letting fish fall into their mouths… you can see them hone in on a fish and chase it, even around rocks and sponges on the sea floor.
In addition to the amazing footage of these creatures flying through the water and swallowing fish whole, the researchers played some of the vocalizations the seals make to each other… long series of chirps and burps and a peculiar thudding noise that reminded me of apes beating their chests… coincidentally, they believe that particular noise is made by males to warn interlopers out of their territory.
The video and vocalizations would have been enough for me, but then one of the project members got up and talked about marine mammal globin concentrations… proteins that protect the brain when the animal does things that would kill most other mammals, like stay submerged in below freezing water. holding its breath for longer than it takes to watch an episode of “Glee.”
One of the many slides she showed was a graph placing various mammals on a continuum based on globin concentrations. Mountain lions, coyote and humans didn’t fare too well, but the whales and seals were off the hook. There is apparently a developing line of research into whether we can learn how to stave off brain death or degeneration from mammals that have these higher concentrations. I just hope they don’t kill them to figure it all out.
Another slide she had compared fast-twitch and slow muscles in various animals – and humans. Cheetahs and greyhounds, like human sprinters, have mostly fast-twitch muscles for those explosive bursts of speed. Marathon runners and narwhals, on the other hand, have very little fast-twitch muscle, because they require endurance more than speed.
The same researcher began her portion of the evening saying that she’d been stopped in the hall by someone who asked what was the point of this research, who really cared how seals hunted in a polar winter, what possible use could it have to humans? She went on this long defense of the research, tying it in to climate change and us needing to sort out animals’ limits so we could better understand our own, blah blah, but I wanted to stand up and say hey, you don’t have to defend your research. You don’t have to apologize for it not being more obviously useful. Knowledge for the sake of knowledge is not only important, it is vital for our species.
Asking “why” for the sake of asking “why” is one of the things that makes us human. That, and being globin-deficient compared with a narwhal.