Bears Get Around: Glacier Bay, Alaska

Allow me to introduce Bergy Bit, a brown bear from Glacier Bay, Alaska.

Like the Canadian province of Manitoba, the American state of  Alaska boasts all three species of North American wild bears: brown (or grizzly), polar, and black.

There may be as many as 45,000 brown bears in Alaska. That’s about 98% of all  the brown bears in the United States, and 70% of all the brown bears throughout North America.

Kodiak bears are a special kind of brown bear that live in the Kodiak Archipelago, off Alaska’s southern coastline. Kodiaks are the largest sub-species of brown bear: females can weigh up to 315 kilograms, and males as much as 635 kilograms! That’s about the same size as polar bears.

Bergy isn’t quite that big.

 

There are between 4,000 and 6,000 polar bears in Alaska, and at least 50,000 black bears.

In the region around Glacier Bay National Park and Preserve, you might see a rare kind of black bear called the glacier bear. These “glacier bears” have a dark undercoat with lighter fur on top, so their fur looks smoky blue or dark grey. 

Now, coming from Glacier Bay, Bergy is of course very interested in glaciers. He would like to tell you more about them.

An alpine glacier is like a river of ice that slowly flows down from high mountains. See the glacier oozing down the mountains behind Dave?

When snow falls in the mountains and doesn’t melt, it builds up from year to year, compacting into ice. When the ice gets too thick and heavy to stay put, it rumbles and scrapes down hillsides and valleys toward lower land.

Some glaciers melt into rivers, while others end in lakes.  

In Glacier Bay, several rivers of ice flow right into the sea; these are called tidewater glaciers.

Bergy sees many cruise ships motor into Glacier Bay. Their passengers like to watch icebergs “calving” off the glaciers. See the big splash in this photo?

Now, if we were talking about cows, “calving” would mean giving birth to a calf! But with glaciers, it means that a huge chunk of ice falls off.  

The Llewellyn Glacier flows into Atlin Lake, in the northwestern corner of British Columbia (these photos were taken from an airplane; you can see part of the wing). The Llewellyn is an outlet glacier that flows from Alaska’s vast Juneau Icefield.

Deep cracks form in the glacier as it grinds downhill. They are called crevasses. The sharp spires of ice are called seracs.

  See how icebergs (that word means “ice mountains”) are breaking off the glacier into Atlin Lake?

  When the pieces of ice that break off the end of a glacier are small, they’re called – you’ve got it – bergy bits. Even smaller chunks of ice are called growlers … grrrr!

All the fine silt, or rock flour, from the Llewellyn Glacier makes the water of Atlin Lake a marvellous turquoise colour. Glacial lakes are typically turquoise because of the rock flour that glaciers create as they slowly grind and scrape over bedrock.

Even though this kind of erosion seems slow, glaciers can change the very shape of mountains. 

The Matterhorn, a famous peak in the Swiss Alps, was once a rounded mountain. Glaciers formed long ago on four sides of the Matterhorn, slowly carving rock away to leave a peak with the shape of a massive pyramid.

There are still many glaciers in the Alps. By the way, the word “alpine” (referring to any high mountains) comes from “Alps.”

You may have read about climate change and global warming. One of the signs of climate change is that glaciers around much of the world are shrinking. While Bergy isn’t a big bear, he doesn’t want to see Earth’s glaciers get too much smaller! What do you think people can do to help?

Story © S. Clouthier

Photos © S. Clouthier and D. Wei