Photographing Weddell Seals from Below the Ice main content.

Let's Talk with Randy Davis about Photographing Weddell Seals from Below the Ice

Part of Hall of Ocean Life.

Randy Davis_thumb

Randy is a marine biologist who made a major contribution to the study of Weddell seals in Antarctica–he developed a camera and monitoring equipment small enough to attach to the backs of the seals. With this tool, he and his team can record on video the behavior of the seals below the sea ice, where they spend 90% of their time. Before Randy's camera, researchers could only speculate about the lives of seals beneath the ice. The work of Randy and his team has recently been featured in Newsweek, The New York Times, Science, Nature, and on CNN.

AMNH: What's so important about your field of study in Antarctica?

Randy: In some ways, our work is a basic science study–we want to know about Weddell seals simply to know more about them. But our work does have real conservation applications too; knowing more about the seals can help us better manage and protect this species, as well as other Antarctic species. We need to know about their habitat and requirements for survival in order to protect them.

AMNH: And what have you discoverved about Weddell seals?

Randy: My interest extends to all marine mammals and birds, but I chose to focus on the Weddell seal for three reasons. First, because of their environment. They live for much of the time under sea ice! We work in the open ocean, so we can't control the seals' movements. The animal is free to go, and to move far, through very deep water; they travel as far as 600 meters from the breathing hole. Since they're mammals, they need to come up for air, and they have to come back to a very particular ice hole to breathe. That hole allows us to keep tabs on them. I also prefer to study the Weddell seal because it is a good diver–the Weddells make deep and long dives. Also, Weddell seals are quite large. On average, they can reach 1,000 pounds. We like to think the technology we're using is very advanced, but it is not as small as we would like it to be. We need a large animal so it will not be encumbered by our camera equipment. Ultimately, the technology will allow us to extend the use of this technique to a wider range of animals. Another good thing about Weddell seals is their mild temperament!

AMNH: And what does the camera you developed allow you to do?

Randy: Weddell seals spend about 90% of their lives submerged; these new cameras allow us to travel with them underwater. We can watch predator-prey interactions; we can track 3-D movements with other sensors. Combined, these are powerful tools–we can study both their hunting strategies and the senses they use to track prey under-ice and underwater. In fact, we just published a paper on our observations, called, "Hunting behavior of Weddell seals."

AMNH: Is it all about what you see through the camera?

Randy: In addition to the cameras, we use sensors to track them. We are logging a lot of variables when they dive: we measure depth, swim speed, flipper stroke frequency, heart rate, body temperature, compass bearing. We also record audio so that we can hear any noises made by the seals underwater or any noises they hear. We use standard dead reckoning to compute the dive path, making a picture of the path with computers. We record the time with all of these variables so we can synchronize them all; that way we know what's happening when, and can figure out how everything interacts.

Field of Study Marine biology, particularly Weddell seals underwater