Where Does Alaska's Wildlife Go?
Alaskans live a cyclical lifestyle, governed by the seasons and the weather. During the summer we play in the backcountry, fish for all we’re worth, and marvel at the wildlife and majestic landscapes all around us. When winter comes, we ski and snowboard, ride snowmobiles (or “snowmachines,” as we call them), mush dog teams and sip hot chocolate while keeping one eye out for the aurora borealis. If you’ve been to Alaska in either season, you’ve probably done some of those things right alongside us.
But we aren’t the only ones following the rhythm of Alaska’s seasons. Keep reading to find out how Alaska’s wild animals navigate those same seasonal swings.
Our first winter survival strategy is also one of Alaska’s greatest spectacles: mass migration, including millions of migrating songbirds and waterfowl that sweep into Alaska every spring, then depart with their newly fledged young in the fall. But you don’t have to be an avid birder to enjoy the migration of the sandhill crane, one of Alaska’s most recognizable birds. From early spring to September, these distinctive, elegant birds can be found through areas near Delta Junction, Fairbanks and Cordova.
One of the most iconic sights in Alaska is another mass migration, as caribou herds numbering more than a hundred thousand animals travel up to 50 miles a day across the Arctic tundra. Alaska has more than thirty caribou herds scattered around the state, so you can also see smaller groups of them in Interior and Southcentral Alaska.
Even humpback whales migrate to Alaska in the early spring to feed in Alaska's productive waters before heading south. But just like the songbirds, cranes and caribou, they return each spring to take advantage of Alaska’s endless summer bounty.
Brown bears are Alaska’s best-known hibernators, and their rush to fatten up on salmon makes for spectacular bear-viewing in hot spots like Katmai National Park and Admiralty Island National Monument. But there are two other bear species in Alaska. Each of which are active in the summer months storing up energy for the winter to come. The smaller and shyer black bears hibernate too, while only female polar bears with cubs will spend their winter in a den.
At the other end of the size scale, tiny ground squirrels also sleep the winter away in their burrows, letting their body temperatures drop to as low as 27 degrees. Marmots and little brown bats hibernate, too. (We have a total of five bat species in Alaska. The little brown bat, or Myotis lucifugus, is by far the most common.)
Hanging Close to Home
Other animals stay active year-round but stick closer to home during the winter, especially if the weather is bad. These homebodies include porcupines, red squirrels and collared pikas. Porcupines eke out a living by gnawing on bark and spruce needles, but squirrels and pikas subsist on food they cached during the summer. If they want to survive, they have to be industrious: The tiny pika, which weighs only five ounces, can create piles of hay that that are up to two feet high and two feet across.
The easiest of these species to spot is, by far, the boisterous red squirrel. They live just about anywhere you’ll find trees in Alaska, and you’ll hear their chattering, scolding cry the moment they decide you’ve stepped a little too close to their territory, no matter what season it is.
As temperatures drop, many Alaskan animals bulk up with a heavy fur coat and extra body fat. But some of them go one better by donning winter camouflage that helps them go unnoticed as they carry out their daily lives. Species that turn mostly white during the winter include snowshoe hares, all three species of ptarmigan, Arctic foxes, ermine and collared lemmings. The lemmings not only turn from gray to white, they also grow larger claws on their forefeet to help them dig into the snow; and ptarmigan grow feathery “boots” to warm their feet and help them walk on snow.
Our last winter survival strategy is also the most impressive. It comes from the tiny wood frog, which is widely distributed throughout the state; this is the only amphibian found north of the Arctic Circle. As winter comes, they dig into the earth, cover themselves in dead leaves and pump most of the water out of their cells, producing a glucose solution that helps protect their cells from dehydration as they freeze.
Eventually, up to two-thirds of the water in a wood frog’s body freezes solid, its heart stops beating and its eyes ice over. It is essentially dead, with only trace metabolic activity in its cells. But when spring comes the wood frog thaws out, hops into its breeding pond—only a few yards from where it hibernated—and starts that year’s cycle of life all over again.