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