James Hrynyshyn
Northern News Services

Vancouver (Dec 10/01) - For most Arctic animals, including humans, the biggest environmental challenge is staying warm. Not so the mighty bowhead whale.

New research carried out on Western Arctic bowheads harvested by Inupiat whalers off the north coast of Alaska shows that, when it comes to regulating their body temperature, the whales have more in common with tropical snakes than they do most other animals.

In fact, according to Craig George and his team with Alaska's North Slope Borough, if a bowhead ever ran into trouble keeping its blood circulating, it would probably overheat, even in the darkest, coldest months of winter.

The problem is bowheads need a thick layer of blubber as a food supply for the long winter months when their prey is in short supply. But that blubber is also an excellent insulator, meaning the whales have to find other ways to shed their body heat.

The answer are huge flukes, often as wide as a third of their body length, to radiate the heat. The large surface area of their tongues and flippers may also help them cool down. Without those mechanisms, collaborator Todd O'Hara told a gathering of marine mammal researchers in Vancouver last week, the bowhead's metabolic rate "would have to be reptilian."

To gauge just how good an insulator the bowhead blubber has become, Craig's team measured the core body temperature of freshly killed whales. At about 33.5 C, it is several degrees above a human's. No surprise there. But what wasn't expected was the finding that a dead whale's body loses almost no heat at all for at least nine hours after it's killed, despite being dragged through the icy waters of the Beaufort Sea.

"The bowhead is more likely stressed by heat" than anything else, said O'Hara.