I was comfortable for roughly about 15 minutes. And believe me, being in that water does slow you down as well. You can keep them from swimming away because they're so cold in this environment. And there before me is an eight, nine or ten-foot Greenland shark. You're in gin-clear water - it's like being in a giant martini. SKOMAL: It's an incredibly eerie world to be in because there's no sound. Which is when Skomal, wearing his scuba gear and dry suit, would descend down through the hole and into the icy water below. To attach the pingers, he and his team dug holes in the ice, cast baited fishing lines into the water, and brought the sharks to the surface, one at a time. SHAPIRO: That is, where it moves underwater. SKOMAL: We used something called passive acoustic telemetry, which basically means you put a pinger on the shark, you let it go, and you set up listening stations around the area to find out what the shark does. So he set out to spy on the sharks, to see if they hung out where the seals were living, in the thick ice layer. He wanted to figure out whether these sharks ate only dead seals, or if they could hunt live seals. You look at a Greenland shark and all you get is this sense of: I'm a completely lifeless individual that's gonna live my life the way I wanna live it, and I'm not betraying anything to you. You know, you look at a dog, you get something, you look at even a snake - you get something - it looks at you, its tongue moves, something happens. SKOMAL: This shark's taking half a minute to move its tail just from one side to the other. SHAPIRO: Too slow, it seemed, to catch a fast-moving seal. So these sharks reflect that - they're very sluggish, very slow. SKOMAL: Life in cold water, it tends to have very low metabolic rates. Scientists are trying to figure out how Greenland shark behave in the cold, Arctic waters. The salt allows the water to plunge a few degrees below freezing without turning it to ice. The second obstacle has to do with the water temperature. SHAPIRO: So the sharks can't see the seals very well. We think the eyeball operates more like a light sensor. SKOMAL: It has a parasite that bores into its eyeball that renders it virtually blind. Because, from his perspective, there are two big obstacles for the sharks. And Skomal wanted to figure out how the sharks hunt down these seals. Nothing eats them, but they eat ringed seals. SHAPIRO: Greenland sharks are apex predators. And we want to know what the implications are for the ecosystem in the Arctic region, and part of that ecosystem is the Greenland shark. SKOMAL: We live on a changing Earth where ice is breaking up, where global climate change is occurring. SHAPIRO: And why were you interested in this question kind of in the large picture? So our goal was to get up there in the Canadian Arctic and try to figure out how this animal behaves under the ice. Due to the fact that this shark lives under six feet of Arctic ice for most of the year, we just don't know a lot about it. Not the most attractive shark I've really ever been in the water with. SKOMAL: The Greenland shark basically looks like a cigar - short fins, big nose. Case in point: the Greenland shark, or Somniosus microcephalus. He's in the water with sharks every chance he gets. SHAPIRO: Skomal is a biologist with the Massachusetts Division of Marine Fisheries. SHAPIRO: And there's one kind of creature that does this for Skomal that gets him on that roller coaster ride again and again. Until one wins, it's a roller coaster ride. But for me, you know, it's that anxiety, that edge, that mix of emotions, the clashing of human logic with human heart. SKOMAL: There's a lot of things that drive human beings to do what they do. Producer Ari Daniel Shapiro reports on Skomal's search for one shark living in an extreme environment. For some researchers, like shark expert Greg Skomal, that edge is the very boundary between their own life and death. CURWOOD: Science research often takes place at the edge, along a frontier.
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