Seal Cams Reveal Fight For Breathing Holes

Dec. 8, 2004 — -- Antarctica's landscape is so harsh it has humbled even the most seasoned adventurers and made prying knowledge from the continent a dangerous enterprise. Little is known about what lies beneath its giant sheets of ice and even less about the few animals that call the frozen continent home -- until now.

The Weddell seal is the only mammal that inhabits Antarctica year-round. Its ability to hunt, reproduce and survive in the coldest, driest, windiest continent on Earth has intrigued scientists for decades. A new book, "The Hunter's Breath" by Terrie Williams, sheds light on this remarkable animal and reveals that even this hardy species has felt the effects of global warming.

During an expedition in 2001 a group of scientists, including Williams, a University of California at Santa Cruz marine biologist, attached tiny cameras to more than 20 of the animals to get a seal's-eye view of the world below the ice.

The research revealed that Weddell seals have the ability to stay underwater for upward of an hour and they can dive down to depths of nearly a mile with no adverse effects. Their front teeth are essential to their survival under the ice since they use them as ice picks to chip away at frozen-over breathing holes.

Most importantly, the team learned that Weddell seals' survival and hunting ability were limited when warming caused icebergs to break off the continent's shelf.

During the expedition, the largest iceberg recorded in Antarctic water, estimated at over 1,000 feet thick and 170 miles long, nearly the size of Rhode Island, slammed into the permanent ice shelf the Weddell seals called home. Some scientists believe that global warming was the main factor that led B-15 to separate from the ice shelf. Upon its impact it shattered the ice shelf in some areas into deep crevasses, trapping penguins. In other places solid ice blocked pregnant Weddell seals from reaching nursery areas.