Glacier Bay’s Bears A Remnant Of The Ice Age

Where glacial ice has most recently retreated, Glacier Bay’s bears rely on the intertidal area for food. Photo by Tania Lewis.
Where glacial ice has most recently retreated, Glacier Bay’s bears rely on the intertidal area for food. Photo by Tania Lewis.

Brown bears are one of the most intensively-studied species in Southeast Alaska. Much of the focus is on population management for hunting. But one scientist studies bears for their sake and not ours. Tania Lewis is the terrestrial wildlife biologist at Glacier Bay National Park. She’s made some breakthroughs in both behavior and genetics, and she can’t help but sing about it.

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I have to admit that in my years as a reporter not many stories — well, make that no stories whatsoever — have ever had a banjo component.

Lewis singing

But there’s more to Tania Lewis than her banjo. The song is also an important part of her story. We’ll get back to it in a moment.

When Tania Lewis started her work in Glacier Bay thirteen years ago, there were many instances of not-very-pretty encounters with the brown bears in the northern part of the bay.

“Like 10-20 per year of people getting their tents squished, their kayaks trashed.”

Lewis says it wasn’t a food issue. Campers are required to use bear cans. It seemed to her as if the bears just liked messing with people’s gear. She gathered some of the state’s top bear experts and came up with a new strategy.

“Stand your ground and not let bears destroy your stuff. We hit that safety message hard, and we continue to, and last year we had almost no incidents.”

This is different from the usual advice about brown bear encounters in the rest of Southeast Alaska. Group together, back away slowly, is more common. But Glacier Bay is a little bit different, and so are its bears. Besides rewriting the park’s bear plan, Lewis is also involved in biological time travel.

“It’s pretty cool to look at the genetic consequences of the Little Ice Age.”

The glacial maximum in Southeast Alaska was 18,000 years ago. But the mouth of Glacier Bay opened as recently as 260 years ago. The animals that inhabit the area — biologically speaking — have been isolated in time. By sampling DNA in the fur of brown bears, Lewis has discovered three distinct populations of animals: bears from the Chilkat region around Haines, bears from the Yakutat Forelands, and bears that are unique just to Glacier Bay

“So what that tells us is that this small group that’s only found in Glacier Bay is sort of a remnant population. A population that was isolated at some point, most likely from a small number of individuals that underwent genetic drift and over time developed their own genetic signature. Now, bears from the east and the west — since the ice has moved back from other places they’re able to get in there — they’re all present in northern Glacier Bay.”

Lewis says the Glacier Bay brown bears are smaller than their cousins, bold but not aggressive. Because the land is new, they rely heavily on intertidal areas for food, which is why they so often stroll through the beachfront campgrounds of visitors to the park.

“I’ve just felt, since I’ve been in Glacier Bay, that the bears in the recently de-glaciated areas are just a little bit unique, and it’s pretty cool to find it genetically.”

Lewis thinks a lot about these bears. She was driving to the university in Fairbanks to defend her dissertation, and wrote a song about the two bears who first found each other in one of the small, habitable areas of Glacier Bay thousands of years ago. She signed up to sing it at the Fairbanks Folk Festival, where this recording was made.

Lewis singing.

Think of it as an ode to the very large, furry Adam and Eve brown bears of Glacier Bay.

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Robert Woolsey is a reporter at KCAW in Sitka.