WEBVTT 00:00:06.000 --> 00:00:11.000 We're here today on McMurdo Sound to conduct a research project 00:00:11.000 --> 00:00:17.000 to study the possibility that Weddell seals use a magnetic sense to navigate. 00:00:17.000 --> 00:00:21.000 We're doing this by attaching instruments to the seals; it records their behavior 00:00:21.000 --> 00:00:26.000 and we then use carefully designed experiments to determine whether the behavior 00:00:26.000 --> 00:00:32.000 matches predictions that we have for a seal, or any organism, that would be using a magnetic sense. 00:00:32.000 --> 00:00:39.000 Imagine your life where you spend ninety-five percent of your time holding your breath, 00:00:39.000 --> 00:00:43.000 and yet performing all the normal functions that you do in your daily life, 00:00:43.000 --> 00:00:46.000 feeding, sleeping, other types of activities, 00:00:46.000 --> 00:00:51.000 but you're doing it while you're holding your breath; and you can only breathe at certain locations. 00:00:51.000 --> 00:00:55.000 Seals do precisely this but if they don't have a chance to breathe, 00:00:55.000 --> 00:00:59.000 they're just like humans or other mammals, they will drown. 00:00:59.000 --> 00:01:04.000 So being able to reliably travel between sparsely-located breathing holes 00:01:04.000 --> 00:01:08.000 is absolutely critical for their ability to live under this ice. 00:01:08.000 --> 00:01:15.000 And we think that has resulted in the evolution of a very precise geo-magnetic navigational ability. 00:01:15.000 --> 00:01:17.000 At least, that's our hypothesis. 00:01:17.000 --> 00:01:23.000 The Weddell Seal is so fascinating because they're doing things that we could never do. 00:01:23.000 --> 00:01:28.000 They're holding their breath for an hour, they're exercising while they're doing it, 00:01:28.000 --> 00:01:31.000 they're going to depths that would just crush our lungs. 00:01:31.000 --> 00:01:36.000 And they can swim, just routinely, at about two meters per second. 00:01:36.000 --> 00:01:40.000 Michael Phelps got a gold medal for going one point nine meters per second, 00:01:40.000 --> 00:01:44.000 So it gives you an idea of just what kind of an athlete these guys are. 00:01:44.000 --> 00:01:49.000 The problem with Weddell Seals and all marine mammals is that once they dive beneath the surface, 00:01:49.000 --> 00:01:53.000 and especially under ice, we cannot observe them. They're very hard to track. 00:01:53.000 --> 00:01:58.000 So, what we've developed over the years is an instrument that we attach to the animal 00:01:58.000 --> 00:02:01.000 that allows us to travel vicariously with them, 00:02:01.000 --> 00:02:05.000 look over their head and see, basically, their world-view under the ice. 00:02:05.000 --> 00:02:09.000 And we do that with this video data recorder which we've developed 00:02:09.000 --> 00:02:13.000 with funding from the National Science Foundation. 00:02:13.000 --> 00:02:18.000 It has an array of sensors and a small video camera with near-infrared LEDs. 00:02:18.000 --> 00:02:24.000 It will record twenty-seven hours of video, programmable. That is, we can spread it over an extended period of time. 00:02:24.000 --> 00:02:29.000 And sensors that allow us to recreate its three-dimensional dive path through the water column. 00:02:29.000 --> 00:02:34.000 Well, based on what is known about other animals that we believe are using the magnetic sense, 00:02:34.000 --> 00:02:40.000 there should be changes in behavior when an animal is in a different magnetic field. 00:02:40.000 --> 00:02:44.000 And so we designed an experiment, a rather rigorous experiment, 00:02:44.000 --> 00:02:49.000 that involves placing the same animal in three different magnetic fields 00:02:49.000 --> 00:02:54.000 and we expect its behavior to be different in those three magnetic fields. 00:02:54.000 --> 00:02:57.000 And so as I said, our instrumentation allows us to look at behavior 00:02:57.000 --> 00:03:04.000 very carefully in three dimensions and so we have a really good opportunity to see changes in behavior. 00:03:04.000 --> 00:03:06.000 We'll be coming back in subsequent seasons. 00:03:06.000 --> 00:03:11.000 We hope to be able to do three to four seals at least per season, depending on weather, 00:03:11.000 --> 00:03:14.000 and come out of this project with a sample size of seals 00:03:14.000 --> 00:03:20.000 that may be anywhere from twelve to fourteen, each with three deployments. 00:03:20.000 --> 00:03:23.000 That will give us the amount of data that we need 00:03:23.000 --> 00:03:28.000 to statistically analyze and look for these hypothesized behaviors.