Friday, December 7, 2007

A Weddell's Winter

Should the cold, gray Midwestern winter begin to depress you, think of the Weddell seal. This large pinniped, the southernmost mammal on the planet, spends its winter in the dark, frigid waters beneath the Antarctic ice. In order to keep from drowning, these seals must keep their breathing holes open by gnawing away the sea ice that threatens to close off their air supply; over time, this activity wears away their teeth and, though most face little threat of predation, many end up starving to death.

When not tending to its vital portholes, the Weddell seal dives for fish, squid, octopi and small invertebrates, including krill. Protected from the cold by a thick layer of blubber, this true seal is able to dive 2000 feet below the surface and remain submerged for more than an hour; a rich supply of myoglobin in its body stores and releases oxygen to its muscles and vital organs, permitting these prolonged dives. Averaging ten feet in length, Weddell seals may weigh up to 1200 pounds; females are generally larger than the males.

Now, as we enter our winter season, Weddell seals are hauling out on the ice to deliver and raise their pups. Enjoying the Antarctic summer, they will bask in temperatures comparable to our Midwestern winter!