While the cow elk are busy raising their young, the bulls stick together in small bachelor herds. Thanks to the nutritious grazing opportunities summer provides, their antlers, covered in velvet, begin regrowing up to an inch per day.
The call of the Sandhill Crane is one of the most distinct and beautiful sounds in the Teton valley. Their return each the Greater Yellowstone Ecosystem each Spring signals the changing of the seasons.
Coyotes are perhaps one the most underestimated members of the Greater Yellowstone Ecosystem. This highly intelligent and adaptable specifies deserves a spotlight. Their success making a living on a harsh landscape is due to a remarkable resourcefulness. I recently watched a coyote over several hours fishing for trout in a river, ambushing waterfowl on the river bank, pouncing in the snow for small rodents, and stealing bites of bison from a recent wolf kill that the pack had left temporarily unattended. The variety of creative ways coyotes utilize to find food is impressive.
For the majority of the year most coyotes run solo, or in pairs as they raise pups, but in the winter it’s not uncommon to see them in packs with up to 5 or more members. This confidence in numbers allows them to take on larger prey, and maybe even to feel more secure as they traverse a winter landscape dominated by their larger not-so-tolerant relative, the wolf.
At first glance these slender weasels appear at a serious disadvantage when it comes to keeping warm in the winter. They have practically no body fat, and relatively little fur in their winter coats, but an ermine has several unique features and strategies to make up for it.
For one, their coat turns from brown to white each winter, allowing them to be nearly invisible as they move through a snow white landscape. Their tail has a black tip on the end, which functions as a decoy luring any potential predators to strike there, rather than a more vulnerable part of the body.
To make up for a lack of body fat and extra fur, they generate body heat with their cranked up metabolism. Essentially, they turn their body into a heater, eating up to 6 times a day. When ermines do take time to rest, it needs to be in an insulated location. The den of a chipmunk or vole they just killed fits the bill perfectly. Another tactic ermines are known to employ is actually lining the inside of a log or den with the fur of their victims to keep warm.
There is little question that the next species in my series of winter wildlife finds the most creative ways to have fun. Humans aren’t the only ones enthralled with the feeling of sliding on snow. While we use skis, boards, or sleds, river otters need look no further than their long and slender bodies. When on land, otters cover ground with a hop, hop, slide, hop, hop, slide movement pattern. Sliding on the snow and ice certainly allows them to travel more efficiently, but spend any time with otters and there’s no denying the routine is as much, if not more, for fun as it is for practicality.
Other than playful antics to keep their mind off the cold, otters have some impressive adaptations and strategies for winter survival. River otter’s lengthy guard hairs, and dense underfur, which traps insulating air, keeps them warm in extreme temperatures. On top of that, oil secreted from the sebaceous gland actually waterproofs their coat, preventing water from reaching their skin. To remain well insulated they must replace the air in their underfur after swimming, and they do this by rolling around in the snow, and yes, you’ve guessed it, playfully.
Since the water temperatures are warmer than the air, otters opt to spend more time underwater. They will often travel and hunt underneath the ice shelves which line the rivers and creeks during winter months. An otter may stay below the ice indefinitely by breathing in the air pockets trapped beneath the ice.
While bison display some impressive adaptations for surviving winter, they, along with other ungulates, share one significant disadvantage during the winter, a lack of speed and agility in deep snow. While this may sound more like an inconvenience, it becomes a matter of life and death when your main predator appears to move through the snow as if it wasn’t there. This is the distinct winter advantage of the wolf. Wolves are made for winter. While their prey struggle and sink in the snow, wolves float relatively effortlessly on the surface. Their secret lies in the design of their paws. A wide round shape, and thin webbing between each toe enables each paw to function as a snowshoe. In the search for prey, a pack of wolves, such as Yellowstone's Wapiti pack featured here, may cover 30 snow covered miles in a day. I encountered these wolves recently on one of my photography workshops in Yellowstone. We followed their tracks for miles before catching up to them along them Gibbon River.
Featured first on this series of posts highlighting wildlife and their unique strategies for enduring Yellowstone winter is the bison. Two key assets equip bison to survive in this unforgiving climate.
The distinct shoulder hump on their back, which is actually a protruding muscle, allows them to function as a 1 ton, living snow plow. Unlike other ungulates, such as moose and elk, which scrape with their front feet to access food under the snow, bison use this muscle to rock their massive heads back and forth exposing grass and sedge buried under several feet of snow. Some bison will opt out on this “snow-plow” technique, preferring to graze alongside thermal features where the warm steam from geysers or hot springs melts the snow on the surrounding grass.
When violent winter storms hit, prompting other wildlife to seek shelter from the chilling wind and blinding snow, bison just plop down where they are and wait it out. Their winter coats are so thick and well insulated that the falling snow doesn’t even melt on their back. In a heavy snow, you can watch the largest land animal North America vanish before your eyes in a matter of moments.
Winter in the Greater Yellowstone marries serene beauty and harsh realities in a way only an arctic like cold can. On some days you may be excused for mistakenly thinking you were located in the polar zone. Last January on my photography worksop we spent a day in the field with low temps reaching -40° F (40° C). Severe cold, blustering winds, and limited food resources present supreme challenges for wildlife to overcome. Nothing has kindled a deeper sense of respect for the fortitude and adaptability the inhabitants of this ecosystem posses than my time photographing them in the winter. The next series of posts over the coming days will highlight individual animals and their unique strategies for surviving, and even thriving in the gauntlet of winter.
An ermine takes a brief moment to stand up and take in it’s surroundings before resuming the frantic hunt for prey at what appears to be lightspeed. It’s near impossible to keep track of these weasels for more than a few moments. They trade a brown summer coat for a white one each winter. Their cranked up metabolism allows them to keep warm by compensating for their lack of body fat.
Shortly after I photographed the ermine, I located a family of river otters, which are also a member of the weasel family. We tend to have negative connotations with the word “weasel”, but some of my favorite animals to spend with and observe are weasels.