Low-profile ringed seals are warming victims

Near perfect nurseries
Holes dug by ringed seals eventually get covered by drifting snow. Within the drift, ringed seal females dig out lairs to give birth and nurse pups.

Unless a polar bear sniffs them out, the lairs are a near perfect nursery for the helpless pups as their mothers dive below the ice to feed on fish and crustaceans.

Female ringed seals exit their breathing holes and start giving birth about April. Some give birth as late as the middle of May. Pups nurse for eight weeks.

"The earliest pups might be weaned is by the end of May," Kelly said. "In June, the later-born pups are still nursing."

Lairs provide insulation that not only helps keep breathing holes open, but also provides a warm shelter for pups, which are not ready for chilly Arctic water.

"The pups are born in this white, wooly coat," Kelly said. "We call it lanugo. It's their insulator. Until they're weaned, they haven't really developed a subcutaneous blubber layer."

Kelly compares the fur coat to goose down.

"It keeps them nice and warm until it gets wet," he said. "Then it stops. It becomes a conductor (of cold) instead of an insulator."

Meteorological data indicates that in 1950s, even late-born ringed seal pups had weaned well before summer temperatures melted snow on sea ice. That's no longer the case.

Snow melt dates since then have crept up by three weeks off Point Barrow, Alaska, according to monitoring by the National Snow and Ice Data Center at the University of Colorado, placing later-born pups at risk for having their snow lairs collapse.

"I'm convinced that the key factor we need to be paying attention to is the relationship, in fact, to the snow cover on the ice," Kelly said.

Canadian scientists have documented unusual weather events, including rain, that led to collapsed lairs followed by a hard freeze that killed pups on bare ice.

A thaw and a collapsed lair followed by a hard freeze can kill pups.

"There's this sort of counterintuitive circumstance where animals are freezing to death as a result of climate warming," Kelly said.

"The big question is, can they make a transition from reproducing in snow lairs, on the ice, to reproducing on land, if the ice isn't there in the reproductive season," he said. "I don't know but that seems like a big question for them."

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