While fall is evident just about everywhere in the lower 48, winter is already moving into Alaska. In honor of the season, please meet a few of the Arctic’s most incredible animals – creatures who endure extreme, dynamic conditions in their own extraordinary way. These truly incredible species highlight what we stand to lose if we fail to preserve our unique Arctic landscapes for generations to come.
The Arctic Ground Squirrel and Its Supercool Slumber
With winter already creeping across the landscape in Alaska, the Arctic ground squirrels are headed more than a meter below the tundra for their annual hibernation.
It’s not uncommon for small rodents to hibernate and turn the dial down on their body temperatures, however, the Arctic ground squirrel is one of the most extreme. Not only are they able to drop their body temperature to -2.9 degrees Celsius (below the freezing point of freshwater and the lowest core body temperature recorded in any mammal), but they are also able to nearly fully shut down neural activity in the brain through this supercooling function.
It’s not a perfect slumber, however. Every couple of weeks during their hibernation, the squirrels will shiver themselves back to a normal temperature of about 36.4 degrees Celsius. They keep this core temperature for about 12-15 hours before freezing into squirrel popsicles once more.
How can their brains handle this kind of extreme temperature swings? Scientists aren’t 100 percent certain, but have seen that during the bouts of shivering, the squirrels’ brains undergo massive growth spurts. Some experts believe learning more about this process could aid in preventing or even reversing neurodegenerative diseases, including Alzheimer’s.
The Arctic Fox and Fantastic Phonics
The Arctic fox is quite similar to the red fox that you may be familiar with, just smaller, furrier, and ranging from white to nearly blue in color. Their shorter snouts, stubbier legs, and smaller, curled ears help to reduce heat loss, a necessary trait for surviving the -50 degrees Celsius temperatures of bitter Alaska winters. The Arctic foxes’ winter coats can keep their core body temperature at a cozy 40 degrees Celsius, while their white coloring helps them blend in better with their surroundings.
Their impeccable hearing, however, is truly the Arctic fox superpower. They can identify the precise location of small prey beneath feet of snow all winter long. To catch their dinner, they leap high into the air and can burrow up to their back legs in snow to snatch their meal below.
Arctic Wooly Bear Caterpillar: Life in Stop-Motion
The Arctic wooly bear caterpillar is truly one of the most fascinating creatures of Alaska.
During the extremely short Alaska summer, the caterpillars spend as much time as they can eating just about any plant they can find (can’t be picky when time is not on your side!). As soon as temperatures begin to drop though, they return to a dormant, frozen state for nearly the entire year. Because it can take so long for wooly bear caterpillars to build up enough energy and calories to make the transition to adulthood, it can take up to 14 years to get from egg to the final moth – the longest lifecycle of any moth.
The caterpillar’s fur, called setae, isn’t there to protect them from the cold weather. Instead it actually helps them to freeze more controllably. It can survive up to -70 degrees Celsius temperatures by breaking down all their mitochondria and producing a form of antifreeze called glycerol.
Additionally, nearly 75 percent of all Arctic wooly bears are killed and eaten by just two species of parasitic wasps and one species of fly. The few that survive to moth-hood don’t get much of a reward either. Once the Arctic wooly bear metamorphizes into moths, they have just a few days to mate and reproduce before they die.
The Wonderful World of Arctic Ice Worms
You might think a glacier would be a fairly lifeless place, but the Arctic ice worm has made these “ice castles” their perfect home.
It’s estimated that nearly 5 billion ice worms can live in a single glacier. And while exceedingly abundant, very little is known about them. What we do know is that despite their chilly surroundings, if they are exposed to even a few degrees below or above freezing, they die.
The Arctic ice worm is loosely related to the more common earthworm, but spends its entire life in ice. They were first discovered in Alaska, but have also been found in other regions of North America including Washington, Oregon and British Columbia. However, even in similar latitudes with similar glaciers, these worms haven’t been found anywhere else in the world.
Musk Ox: Ice Age Survivors
Musk ox have a fascinating relationship with Alaska. They are one of the few remaining survivors of the Pleistocene Ice Age, likely appearing in North America after crossing the land bridge connecting to modern-day Europe more than two million years ago.
Despite their stalwartness through the Ice Age, by 1920, colonizers had fully extirpated the musk ox from Alaska. Ten years later, researchers brough 34 musk ox from Greenland to Fairbanks and then later to Nunivak Island to try and repopulate the region. By the mid 1960s, the herd grown to more than 750 and traveled through to Nelson Island, the Arctic Refuge, Cape Thompson and the Seward Peninsula.
Today, there are more than 5,000 musk ox in Alaska.
Like other Arctic mammals, they’ve had to adapt to freezing winter temperatures, blizzards and long periods without sun. To survive, they’ve developed a double layered coat – an outer coat that looks more like hair than fur and a shorter undercoat called qiviut. Qiviut might be one of the warmest and most durable natural fibers, more hearty than sheep’s wool, but softer than cashmere. To maintain their body temperature through the summer, they shed their qiviut where it gets stuck on willows and shrubs and is still collected by crafters today.
In addition to their impressive coats, musk ox also have the ability to shut off thermal regulation in certain parts of their bodies (like their limbs) to conserve heat in their core. The hemoglobin in their blood is also three times less temperature sensitive than human blood and allows them to more easily move oxygen into colder tissues, preventing damage.
Stoats: Skilled Showmen and Savvy Stalkers
Stoats, also known as ermines, belong to the weasel family and are actually closely related to mink, martens and wolverines, as well as both river and sea otters. They are quick and feisty creatures who must eat at least 40 percent of their body weight every single day. The stoat is always on the hunt.
During the summer, the stoat is a light brown color, but come winter they shed their brown coat and shift to a more camouflaged all white – this is also when they technically go from a “stoat” to an “ermine.”
Photo Credit: © Steven Kazlowski