ARCTIC ANIMALS THAT TURN WHITE IN THE WINTER
Some animals in the Arctic and other places with a lot of snow turn to white in the winter and change back to their original color after the snow melts. These animals are vulnerable to attacks from predators in the spring when they are still white and their world is dark colored. The same holds true to some degree in the autumn after the first snow and they are still dark colored. Camouflage is important for animals living in the tundra because there are no trees of large bushes or anything else that be used as cover or hide behind.
Animals that turn white for winter include Arctic foxes, Arctic hares, snowshoe hares, ptarmigan, caribou and ermine. M. Saleem wrote in webecoist.com: “Starting in September, the Arctic Fox sheds its brown coat, opting instead for a white one to help it through the inter. As summer begins to approach again, the white coat is once again replaced with a brown one, allowing it to hide better in the earthy tones of its habitat. [Source: webecoist.momtastic.com ***]
“Just as with the Arctic Fox, the transformation in the Arctic Hare is an absolute one. Though they are brown with flecks of black during the summer, they turn a beautiful and pure white during the winter months. This not only helps them keep warm but provides much needed camouflage in the snow when they come out of their nests or burrows. The Ermine, also known as the short-tailed weasel, is the smallest member of the weasel family. They are found all over the Arctic regions of Asia, Europe, and North America. ***
“The Ptarmigan, or Rock Ptarmigan as it is known in North America, is a popular game bird that molts from brown to white with the exception of the tail which retains its original color of brown or black. These birds prefer higher elevations and barren regions, and are often found perched in rocks or sitting in the snow (hiding) than in trees where they could be spotted easily in the winter. ***
“In general, the coat of the Caribou alternates between brown and white, but it is never wholly one or the other. In the summer time it is predominantly brown but the neck region retains a dirty white color, while in the winter, the white spreads and becomes clearer though the brown never completely goes away. This difference in the degrees of color change varies depending on the regional habitats of the Caribou.” ***
The Arctic fox ranges farther north than any other land mammal and is the smallest wild canid found in northern latitudes. About the size of a large domestic cat, they hunt lemmings underneath the snow even though they can’t see them. Arctic foxes range across the enture Arctic region and probably total several hundred thousand but their numbers vary with wide fluctuations because of variations in the lemming populations. Most arctic foxes turn white in winter, but some have brownish blue fur. Many bluish one live in coastal areas, where they blend into dark backgrounds. Around July white foxes shed their winter coats for the brown and cream fur of summer. White foxes can be easily seen against the black earth in the summer. Blue foxes also turn dark brown that time of year. [Source: John L. Eliot, National Geographic, October 2004 ==]
John L. Eliot wrote in National Geographic, “Patrolling vast expanses, this wanderer of the far north has adapted to cycles of feast or famine. Let a raven drop a bone onto the ice or the aromas from a hunter's cook tent waft from a mile away, and a small white shadow will soon materialize to investigate—an arctic fox. Near Hudson Bay a fox's curious nose pokes around a knifelike ridge of ice. "It is the friendliest and most trusting of the North American foxes, although it is characterized . . . as 'impudent,'" wrote naturalist Barry Lopez. ==
“In winter these small, almost delicate foxes range over huge areas seeking rodents or mammal carcasses. Some cross more than 600 miles (966 kilometers) of pack ice in 40-below-zero conditions. The species expanded in the Arctic at the end of the last warm inter- glacial period, about 120,000 years ago. Evolution equipped them with small ears, short muzzles, and thick fur to minimize heat loss. Their feet are fur-covered, like hares'—hence their scientific name, Alopex lagopus, or "hare-footed fox." ==
Kathy B. Maher of National Geographic wrote: “In Finland the northern lights are called revontulet, or "fox fires," harking back to an old folk tale about an arctic fox running in the snow and touching the mountains with its fur, causing sparks to fly up and illuminate the sky. In another version of the story, the fox throws sparks into the sky by whipping snow upward with its brushlike tail. In northern Lapland, the aurora borealis can be seen more than 200 nights a year, making for some very busy foxes!” ==
Prey and Dens of Arctic Fox
John L. Eliot wrote in National Geographic, “Hunting ringed seal pups born in small caves under the snow in Norway's Svalbard archipelago, a fox rears up, jumps on a den, and dives in head first. Pups often escape from the den into open water. The foxes' keen noses can detect such lairs more than a mile away. Near Hudson Bay, foxes tag along with polar bears in winter to scavenge leftover seal carcasses.” [Source: John L. Eliot, National Geographic, October 2004 ==]
“Arctic foxes' most vital food source—or lack thereof—is a little fur ball called the lemming. Problem is, the rodents aren't reliable (See lemmings below). Some parts of the arctic foxes' range, have no lemmings, so foxes there feed on seabirds, geese, and their eggs in summer. In winter the opportunist foxes scavenge seal and reindeer carcasses. Compared with Hudson Bay, Svalbard's fox population is more stable. "But because they rely on marine species, they have high concentrations of contaminants like PCBs," says Eva Fuglei, a wildlife biologist at the Norwegian Polar Institute, who is studying the effect of the toxics on the foxes' disease resistance and reproduction ==
The mating season is usually around March and young foxes emerge from dens in July as wildflowers replace ice and snow. “When the pups were about two weeks old, their mother moved them one by one to a new den. Heavy rain may have prompted her decision, or she may have sought a cleaner site. Dens are often used by many generations—for as long as 300 years. The burrow complex may spread over 500 square feet (47 square meters) and have a hundred entrances, offering the pups quick escape from predators. Owls and eagles prey on young and adults, as do red foxes, a species from the south that overlaps the arctic foxes' range. Red foxes, which are considerably larger, also compete with arctic foxes for denning sites.” ==
Arctic Fox Reproduction and Lemming Boom-and-Bust Cycle
John L. Eliot wrote in National Geographic, “Lemming numbers have a huge impact on litter size. In 2002, when lemmings crashed in much of Canada, photographer Rosing found two sleepy pups in a den of only seven on Victoria Island in the Canadian Arctic. The following year, when lemmings were plentiful, "this den near Churchill had 13 pups", says Rosing, "and it was littered with lemming and bird carcasses." One of the den's adults for ages to feed its young.[Source: John L. Eliot, National Geographic, October 2004]
In good lemming years one female may have up to 20 pups, and local arctic fox populations boom. When lemming numbers plummet, many arctic foxes starve in winter, leading to fewer and smaller litters. Critical to foxes during lean lemming years, about 100,000 snow geese nest on La Pérouse Bay near Churchill. "I found 72 geese feet in one Churchill den," says ecologist James Roth In years when food is abundant, adults feed their young through the summer until autumn, when the pups disperse. In lean years the pups leave the den earlier, to hunt on their own in a land where success is never a sure thing.
Arctic hares, or polar rabbits, are hares which have adapted harsh polar and mountainous conditions. habitats. They have thick coats of fur and usually dig holes in the ground or under snow to keep warm and sleep. Arctic hares look like rabbits but have shorter ears, are taller when standing. They can travel together with many other hares, sometimes huddling with dozens or more, but are usually found alone. The Arctic hare can run up to 60 kilometres per hour (40 mph). Typically they 48 to 67 centimeters (19 to 26 inches) long with a three to eight centimeter long tail and weigh three to seven kilograms (6 to 15 pounds).
According to National Geographic: “The arctic hare lives in the harsh environment of the North American tundra. These hares do not hibernate, but survive the dangerous cold with a number of behavioral and physiological adaptations. They sport thick fur and enjoy a low surface area to volume ratio that conserves body heat, most evident in their shortened ears. Hares are a bit larger than rabbits, and they typically have taller hind legs and longer ears. [Source: National Geographic]
In winter, they sport a brilliant white coat that provides excellent camouflage in the land of ice and snow. In spring, the hare's colors change to blue-gray in approximation of local rocks and vegetation. Arctic hares are sometimes loners but they can also be found in groups of dozens, hundreds, or even thousands of individuals.
Unlike many mammals, arctic hare groups disperse rather than form during mating season. Animals pair off and define mating territories, though a male may take more than one female partner. Females give birth to one litter per year, in spring or early summer. Two to eight young hares grow quickly and by September resemble their parents. They will be ready to breed the following year.
Food can be scarce in the Arctic, but the hares survive by eating woody plants, mosses, and lichens which they may dig through the snow to find in winter. In other seasons they eat buds, berries, leaves, roots, and bark. Traditionally, the arctic hare has been important to Native Americans. These fairly plentiful animals are hunted as a food resource and for their fur, which is used to make clothing.
Lemmings are small short-tailed animals that look like a miniature rabbit and are related to the meadow mouse family. The survive in the summer by eating lichens and mosses and survive the winter by burrowing themselves under the snow.
Lemming are very prolific. They can became pregnant at the age of 14 days (more often around two months) and can reproduce five or six liters of 4 to 6 offspring annually. The gestation period is only thee weeks. According to the Guinness Book of Records, one pair produced eight litters in 167 days. Theoretically a single pair of lemmings could produce 10,000 lemmings in a single years, Oredatris and lack of food are the main factors that keep their numbers in check. Frequently the animals over produce to the point they outstrip the food supply.
Lemming populations surge and crash with a high degree of regularity at intervals of about once every four years. In a very short period the numbers of lemmings dramatically increase and then virtually disappear. In the 1500s, it was seriously suggested that lemming dropped from the sky. No other plausible explanations could be offered as to why their population could increase so much so suddenly.
Lemming Mass Suicides?
It has been suggested that lemmings die off in mass suicides. According to one take on this view massive groups of lemmings march in a straight line to some unknown destination, devouring everything in their path. If the lemmings come to a lake, they try to swim across it, with many drowning in the process. If they encounter a boat they climb over it and continue in their straight line. "If they come across a man they glide between the legs," one scientist wrote. "if they meet with a haystack they gnaw through it. If a rock stands in their way they go around it in a semicircle and then resume the straight line of their match."
Any attempt to disrupt their march is met with great resistant—fighting and barking. Finally when the multitude reaches the sea, they continue right on marching to their deaths, or fall en mass from cliffs. A few stay behind and return to their home range to breed. There are so few of them at this point that they are rarely seen until their population begins growing once again and the cycle continues.
It turns out the stories of mass suicide are a myth. "They don't commit mass suicide: That's a myth popularized by an old Walt Disney film," James D. Roth, an ecologist at the University of Central Florida, told National Geographic, "But lemmings do follow a natural boom-and-bust cycle. About every four years they're super-abundant, then they crash for one year, and gradually increase until the next peak." Much of the blame for the suicide myth has been placed on the 1958 Disney nature film White Wilderness, which shows masses of lemming hurling themselves into the sea. The 1983 Canadian documentary, Cruel Camera, claimed the scenes were staged: that the film maker James Alga purchased lemmings from Eskimo children and herded them into water.
Andrew Tarantola wrote in gizmondo.com: “The film was made in Alberta, Canada. Lemmings aren't native to that region so the production crew instead imported a few dozen of the animals for the shoot. Second, the species of lemming that they lined up does not migrate. Some species of lemmings do migrate, sure, when their cyclical population growth presses some individuals to move to less crowded areas. But you'll never see a herd of migrating lemmings like you do in the film As such, the crew actually had to employ a snow-covered turntable to make it appear that they were "migrating" when they were really just running in circles. After the crew had a sufficient number of these migratory shots, the animals were herded over to the bank of a nearby river and unceremoniously chucked into the water, where they drowned. Thus the myth of suicidal lemmings was born. It wasn't until 1982, when the Canadian Broadcasting Corporation's investigative journalism program The Fifth Estate ran an expose entitled Cruel Camera on Hollywood's sickening treatment of animals... But, by that time, White Wilderness had already won an Academy Award for Best Documentary Feature—and the myth of the cliff-jumping lemmings was already set in stone.”
Explanation for Lemming Population Declines
A study released in 2003 on lemmings in Greenland indicated that the primary reason that lemming populations crash so suddenly and dramatically is because of predators not mass suicides. Observations of collared lemmings over a 1 year period showed that the decimation of lemming populations was the result of four primary predators: snowy owls, long-tailed skuas (a kind of seabird), arctic foxes and stoats (short-tailed weasels or ermines).
The study found that tundra where the lemmings lived provided abundant food sources and soft soil for them to burrow in. Their high reproduction rates meant that they could quickly produce large numbers of themselves. When their numbers rose to a certain level the animals mentioned above began eating more and more and more of them. One pair of snowy owls brought up to 50 lemmings a day aback to their nest to feed their chicks. Stoats also can reproduce frequently so that when lemming offered a plentiful food source they began reproducing more quickly and ate more lemmings.
Another theory for the lemming boom and bust cycle that has been given some serious consideration is the lemming’s eating habits. The animals mostly eat sedges and grasses which produce a chemical that neutralizes the lemmings digestive juices. If the lemming eat moderately, which they do in most situations, the plants stop producing the chemical after 30 hours. When the animals eat intensely, which they do when the population explodes, the plants keep producing the chemical, which causes the lemmings to eat continuously but still be hungry, According to the theory, they swim into lakes and drown themselves as they search of food after the land has been stripped.
Text Sources: New York Times, Washington Post, Los Angeles Times, Times of London, Lonely Planet Guides, Library of Congress, U.S. government, Compton’s Encyclopedia, The Guardian, National Geographic, Smithsonian magazine, The New Yorker, Time, Newsweek, Reuters, AP, AFP, Wall Street Journal, The Atlantic Monthly, The Economist, Foreign Policy, Wikipedia, BBC, CNN, and various books, websites and other publications.
© 2008 Jeffrey Hays
Last updated May 2016