While past research has described the specie in great detail, a new study has found that Antarctic seals may be using the Earth's magnetic field as a natural GPS while hunting.
Weddell seals, native to the Antarctic, have adapted to dive deep below the surface while hunting, but demonstrate an uncanny ability to find holes in the ice to breath. Researchers believe now that they can do this because of their use of the Earth's magnetic field, which allows the seals to have innate spatial awareness, like a built-in positioning device.
"This animal, we think, may be highly evolved with an ability to navigate using magnetic sense in order to find ice holes some distance apart and get back to them safely," said lead author of the study, Randall Davis of the Department of Marine Biology at Texas A&M University.
Davis has been studying Weddell seals for decades along with Terrie Williams, a professor of ecology and evolutionary biology at the University of California, Santa Cruz and another colleague, Lee Fuiman, associate director of the University of Texas' Marine Science Institute in Port Arkansas. Collectively, the three researchers and their teams have decades of experience with the seals, and are constantly surprised to find the newly uncovered idiosyncrasies of the breed.
Fuiman, for example, was struck by the data from the beginning, as the seals were always able to find the breathing holes with remarkable precision.
"The animal always found its way back" Fuiman says. "It's like he knew exactly where the hole was. I couldn't figure out how they would do that. How did they know where they were by the time they turned around?"
This research is impressive but not conclusive the researchers say.
Noting the importance of this discovery, the team now will try to determine if the seals are using magnetic lines much like homing pigeons do to find their way back home. For the next three years, the team will work with a handful of seals outfitted with video and data recorders and released in the McMurdo Sound, where researchers have precisely mapped the magnetic field.
"There should be changes in behavior when an animal is in a different magnetic field," Fuiman says.
Comparing their maps of the magnetic field with dive data from the seals, the researchers should be able to determine if the seals are, in fact, utilizing changes in the magnetic field as a method of navigation deep under the ice. But that's not all. The group also plans to return to Antarctica in August toward the end of the Antarctica winter when there are still twenty-four hours of darkness.
The team of researchers admit that it is possible that Weddell seals simply use other strategies for locating breathing holes with ease, with one possibly raised that the seals use piloting - using under-the-ice visual features such as cracks to navigate their way around. But from preliminary results Davis and his colleagues are hopeful that they're not only right, but that they've pinpointed the evolutionary technique that allows these creatures to survive the frigid seas.
