About 200 species of birds migrate to the North American boreal forest every summer to raise their young. They come from the United States, Canada, Mexico, Central and South America, and even as far away as Australia. Africa, and the Antarctic.
What makes the far north so attractive that a bird would literally risk its life, flying vast distances to come here?
There are several reasons why birds such as Swainson's thrushes, peregrine falcons and golden plovers would travel 7,000 miles from southern South America to nest and raise their young here. One reason lies in the availability of wild land and relative safety where the males can set up breeding territories and females can find nesting spots. Much of the boreal forest is far from urban areas, industrial developments, and other human activity.
But perhaps the most important reason to journey so far is the long northern days, which bring lush plant growth and an incredible abundance of insects like mosquitoes, which are essential for birds to feed their growing nestlings.
For many thousands of years, caribou have been awakening the quiet world of the north as they've journeyed across the landscape during their annual migrations. In fact, caribou bones in northern Alaska have been dated to at least 28,000 years ago, during the late Pleistocene, when they shared the tundra with long-vanished mammoths and mastodons.
More than anything else, what distinguishes this member of the deer family from all other mammals of the north is their nearly continuous movement.
For example, moose tend to stay in one area to feed—some even spending their whole lives within a five mile area—but caribou are constantly on the go, dancing across the land, from wintering grounds, to calving grounds, to their summer range, and back again.
Caribou don't travel in a straight line either, so they cover many more miles than the distance between summer and winter ranges would indicate. In fact, satellite tracking has shown that caribou in the Porcupine herd travel more than 3,000 miles during their annual migration from the boreal forest in Canada to the North Slope of Alaska.
It's a sure thing that caribou will migrate, but their exact route is another question entirely. Trying to guess what mountain pass, what valley, what river a caribou herd might cross is anything but an exact science…hunters know well that expecting a caribou herd to take the same route twice is a recipe for a hungry winter. This scattered and varied travel also helps protect the slow-growing and fragile tundra plants—on which caribou depend—from overgrazing.
As whales go, humpbacks aren't the biggest—a "mere" 40-45 feet long compared to 60 foot sperm whales and 100 foot blue whales—the biggest animal that has ever lived. But humpbacks are arguably the best loved and they're definitely the biggest show offs of all the cetaceans.
No other whale puts on so many spectacular acrobatic performances. Humpbacks are known for their leaps—enormous bodies bursting up into the air and crashing down in massive eruptions of spray. They also seem to enjoy lobtailing—an explosive crashing of their tails on the surface—and they often exuberantly slap the water with their great wing like flippers.
Humpback whales are also famous for their highly choreographed bubble net feeding—10 to 12 gaping mouths bursting through the surface at once. In all these ways, humpback whales put on an awe-inspiring show that thrills first time whale watchers and seasoned research biologists alike.
There is simply nothing like watching these 40-50 ton animals go through their paces. And that's just what we can see from the surface. There's much more to a humpback whale's life story going on underwater, and it's just as fascinating as what's happening at the surface.
In the traditions of Koyukon Indian people—who live near the Arctic Circle in Alaska's interior—cold is not just an element of the physical environment; it is a powerful, conscious, and sensitive spiritual being. If someone offends this temperamental spirit, it can cause dangerously cold weather.
Village elders warn: "You should never brag about how tough you are, like saying the cold could never get the best of you." If someone does that, they advise, "The cold might teach them a lesson." And in the wilds of the far north, it could be a fatal one.
Inupiaq Eskimos on the arctic coast, and Athabascan Indians in the interior have thrived for thousands of years through the extremes of high latitude winters. They are among the world's greatest experts in dealing with deep cold. Long before the arrival of Euro-Americans, these people had perfected some of the world's warmest clothing and ingenious shelters; they learned the best ways to behave in extreme cold; and they mastered the art of using cold for their own benefit.
Traditional skin clothing allowed Inuit people to thrive in the earth’s most challenging environment. This 1965 photo shows the late Andrew Ekak on the sea ice far offshore from the village of Wainwright. Photo credits: Richard Nelson
Meeting the Great Bear
An autumn evening in Denali National Park; the tundra hills cloaked in a brilliant mosaic of gold, amber, and purple; a dusting of fresh snow on the high peaks. From the nearest ridge comes a clatter of tumbling rocks…and the source becomes quickly, startlingly clear.
A grizzly bear—excavating the hillside like a long-clawed backhoe. Nose to the earth, the bear seems oblivious to everything except the freshening scent of his prey—an arctic ground squirrel deep inside a stony burrow. The grizzly's massive shoulder muscles ripple beneath his dense coat of light tan fur; his body heaves up and down; his stocky hind legs brace against the slope.
Then a tiny squirrel bursts out from the fracas with the enormous bear inches from its tail. The air is alive with sounds of thudding paws and huffing breaths…but within seconds everything falls silent. Suddenly still, the grizzly peers down into a burrow, as if he's deciding whether to give the lucky squirrel a reprieve or dig again. Then he turns, rumbles a short ways along the slope, rolls back on his enormous haunches, and stares off toward the distant northern sunset.
Summers in the far north can be a time of lush and lavish living for the animals—plenty of fresh new plant growth for the vegetarians, lots of insects and nectar for birds, berries and salmon for bears, and for wolves there's often an abundance of voles, mice, and snowshoe hares. The endless days of nonstop eating allow many animals the luxury of putting on fat.
But summers are fleeting and winters long—up to 8 months—and brutally cold. Temperatures can plunge to minus 70 degrees. Gales make it feel even colder, and deep or drifted snow can make simply moving around an energy-draining ordeal.
Of course, if you can fly, one choice is to opt-out of winter all together.
Alaska's migratory birds do just that. Some birds, like loons whose summer lakes are frozen in winter, only go as far as the coasts of Alaska, Washington, and Oregon. Robins only need to reach places with frost-free ground, so they can hunt for worms and insects. Other birds go for the relative warmth of the southern US, and some take advantage of the tropics and subtropics—enjoying two summers.
Arctic terns take migration to the ultimate extreme—after a summer in the far north they spend their "winter" in Antarctic waters, so these amazing birds live most of their lives in perpetual daylight.
But what about the animals who stay?
Some birds, like ptarmigan, stick it out through the long and unimaginably tough northern winters. And most other animals—the walkers and crawlers and swimmers—simply don't have the option of leaving.
To stay and tough it out—to survive at 40…50…60 degrees below and colder—animals have evolved some ingenious and fascinating adaptations.