Chapter 8: Life is hard for Arctic plants and animals
In This Chapter
- Arctic plants are low hardy midgets
- How animals adapt to survive
- Lemming population swings set the tempo for Arctic life
- Animals that eat anything
- A 10,000-mile trip with a tiny bird
- The ups and downs of musk oxen
- The secret difference between reindeer and caribou
In summer, the Arctic’s land is cold and windy. In winter, when night falls, the land freezes solid. Yet plants and animals abound: those few species that have adapted to Arctic extremes. Just a few inches below the surface, the earth never thaws. This permanently frozen ground, the permafrost, nourishes no life. The land above is called tundra and supports plants of a peculiar nature: those that live close to the ground.
Land animals, like plants, of course have adapted to the cold and wind, but in a wider variety of ways than plants. They have evolved a variety of strategies for staying warm and obtaining and conserving the food energy they need to stay alive.
Plants Hug the Ground to Survive
No trees grow here, except along great rivers. Plants can’t push roots into frozen ground and frozen cells die. Sensibly, plants snooze under snow blankets, awaiting the few weeks in the Arctic summer when tundra thaws. As we saw in Chapter 3, short plants can grow in the active layer of the terrain. Other plants — lichens — survive on bare rock.
The harsh climate cripples or kills weak plants: low temperatures, continuous daylight in summer, continuous night in the winter, infertile soil that heaves and buckles with freezing and thawing, permafrost, strong dry wind and blowing snow. Few species survive these conditions. Those that do are rugged dwarfs whose shallow roots skim the top of the permafrost.
The active layer of Arctic terrain (U.S. Fish and Wildlife Service)
Low creeping shrubs, grasses, thick growths of lichens, mosses, sedges, and herbs are the survivors. The Arctic has more than 15,000 different kinds of lichen and 400 species of flowering plants: blue-spiked lupine, wild crocus, mountain avens, Arctic poppy, and saxifrage — tough midgets all. Arctic plants grow fast, maturing in record time. They jump start in the spring when the snow still covers the land. In six weeks, they flower and seed: using 24-hours-a-day energy pouring from the sun.
In July the tundra flowers with brilliant colors: yellows, pinks, blues, purples, and reds. By late August it’s over, growing ends, and plants await their blanket of snow. Life sleeps in compact mounds, tough stems, roots, seeds, and spores.
How Plants Survive
Tundra plants can grow at cooler temperatures (27° F to 36° F, -3° C to 2° C) than any other plants on Earth. The low plants bask in the heat of the dark, warmed soil. Most plants are dark to absorb heat and hairy to keep it. Some plants grow in clumps to break Arctic winds and protect each other. Other plants sprout dish-like flowers that track the sun.
Animal Survival Means Not Being Eaten
Survival is a simple matter of getting enough energy and water and not being eaten. Not easy, though, where food is scarce, water is frozen, and predators lurk. The winners (among mammals) include: caribou, musk oxen, Arctic wolf, Arctic fox, Arctic weasel, Arctic hare, and lemmings. The fittest animals have survived by adapting their bodies and behavior.
Animals Find Ways to Hoard Heat
To survive, animals must hoard heat. Mammals grow thick winter fur in two layers: a soft dense underfur like a wooly blanket, covered by an outer layer of long slick hairs that shed water, snow, and wind. Caribou and polar bear develop hollow hair for extra insulation and buoyancy. Birds grow lush downy feathers.
Animals grow big. The bigger the animal, the less surface area (per unit volume) she presents to the cold and the easier it is to stay warm. That’s why polar bears are bigger than bears farther south: they’ve adapted.
For the same reason, animals evolved round shapes. Anything that sticks out — ears, snout, or legs — can freeze. So, Arctic hares, for example, have short ears close to their bodies.
Specialized Tools and Coverings Aid Survival
Over the eons, species developed special tools and coverings to survive. Floundering in snow consumes energy so hares have large feet like snowshoes. Caribou hooves flex to grip uneven tundra and spread for snow travel or river swims. In autumn, the front feet of collared lemmings develop two huge claws to shovel into tundra snow. Arctic foxes grow long hairs on the soles of their feet to give them traction on ice and extra insulation.
Some animals camouflage, becoming white in winter and brown in summer. Arctic hares, ptarmigans, Arctic foxes, collared lemmings, and Arctic weasels all change color and are called "varying" hares, etc. for this reason.
Some Spend Winter in Deep Freeze
A few animals have evolved the ability to survive freezing during winter, then thawing in the spring. It is a dangerous expedient. Freezing usually ruptures cells, killing the animal.
However, wood frogs, wooly bear caterpillars, and a few insects in the Arctic can freeze successfully. More than half their total body water freezes between the cells. The cells themselves contain natural antifreeze so they don’t freeze and burst.
Some Head South for the Winter
Some birds and animals migrate to find food and escape cold. The Arctic tern follows summer by flying 11,000 miles between the Arctic and Antarctic each year. Caribou herds shuttle hundreds of miles between the tundra and tree lands.
Others live under the insulating snow. Lemmings almost never appear on the surface during winter. Hares shelter under shallow pits in the snow and also sit atop snowdrifts on the lee side of boulders. David R. Gray of the Canadian Museum of Nature measured wind speeds and found these spots most sheltered of all locations including hollows at the base of the boulders.
Lemmings make a large nest of sedges and grasses on the surface and let snow cover their home. They forage in the freezing space (-13° F or -25° C) between ground and snow. Snow supplies good insulation, which means under it is warmer than in the open and that allows them to survive.
Moving Up the Food Chain
Energy counts in the Arctic and flows from Sun to plants to plant eaters to meat eaters. Night, however, lasts as long as four months in the northernmost Arctic land areas. Animals wouldn’t survive even one winter without the energy stored in plants. All winter, plant eaters continue to eat plants. Meat eaters continue to eat plant eaters and creatures survive the long night.
Lemmings Control Tempo of Arctic Life
Lemmings control the tempo of life in the Arctic by swinging their population from high to low numbers about every four years. Other species dance to their rhythm. Nearly every carnivore in the Arctic dines on these small rodents, about the size of a mouse. Consequently, when lemmings crash, predators die, especially the young.
Few if any snowy owlets and Arctic fox pups live during times of lemming dearth. Only pups born during a year of lemming abundance survive in sufficient numbers to sustain the fox population. Foxes dwindle until the next good lemming year.
Nobody knows why lemming numbers fluctuate so. What’s more it isn’t a local phenomenon. The numbers are high or low frequently over a large area at the same time. Perhaps lemmings weed out their weak. When the population nosedives, the numbers hover scarily close to zero. It approaches species extinction. Yet the strongest lemmings survive and the species continues.
Various theories about lemmings have been proven false or, at least, remain unproven.
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They commit mass suicide. There are no authentic accounts of suicides
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Predators overeat lemmings. No, instead, lemmings control predator population.
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Epidemic diseases sweep through lemmings. Nope, virtually no disease occurs during some declines.
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Lemming food runs short: Food does vary but nobody has been able to show a cause and effect.
Lemmings are aggressive little creatures that fight as their numbers increase. The stress of overcrowding may change hormone levels, which can decrease birth rates. Also, with enough population stress, lemmings kill each other.
Lemmings
- Distribution: five Arctic species that live in Canada, Siberia, and European Russia
- Size: stout bodied, 4-6 in (8-15 cm) long, with 1 in (3 cm) or less tail
- Diet: willows, cranberries, sedges, Arctic cotton, and mosses.
Arctic Hares Put On New Winter Coats
The Arctic (varying) hare usually changes fur color with the seasons except for those living on high Arctic islands — where the land is always white. Hares living this far north find the living rough enough that they band together into groups of up to 200. Surprisingly, they don’t huddle together though. In fact, if one gets within a yard (meter) of another, the approached hare attacks.
They have many enemies — gyrfalcons, snowy owls, Arctic foxes, and wolves — but only when they’re young. Few predators, except wolves, bother adults. If a hare senses danger, she stands on her hind feet and looks around. Bounding like a kangaroo, she takes off, hitting speeds better than 30 mph (50 kph) and uses jinks — quick evasive turns — to escape.
Arctic hares
- Distribution: in the tundra of North America, Newfoundland, and Greenland
- Size: 21 in (53 cm) long, with 2 in (5 cm) tail.
- Unique features: Big powerful hind legs with hairy mats on soles of feet—snowshoes.
- Diet: willow leaves, bark, shoots, grasses, and herbs
Arctic Foxes Wander Widely
Arctic foxes prowl the tundra for food, including even the smallest and most remote islands north of Canada and Greenland (They sail on ice floes to reach these places). Arctic foxes roam within 300 miles (485 km) of the North Pole.
They will eat almost anything and follow polar bears to scavenge like jackals follow lions. The bears eat only blubber from seal kills; the foxes gobble the rest.
Arctic fox, North Slope of Alaska (National Oceanic & Atmospheric Administration NOAA)
In the summer, when food is abundant, foxes kill more than they can eat to cache the excess in their dens under stones and in crannies for lean winter months. One such store held 50 lemmings and 30 to 40 auks, each lined up side by side, with each head neatly bitten off and tails pointed in the same direction — a tidy mind at work.
Arctic foxes
- Distribution: in the tundra and coastal areas of North America, Iceland, Greenland, Scandinavia, and Siberia. Found farther north than any other land mammal (other than polar bears)
- Size: 20 in (50 cm) long, with 12 in (30 cm) tail.
- Unique features: Big bushy tail helps it change directions quickly and keeps nose and feet warm when wrapped around them.
- Diet: birds, eggs, lemmings, hares, fish, reindeer calves, berries, shellfish, and carrion if desperate
Birds Flock to the Arctic in Summer
In late May and early June, birds flock to the Arctic eager to gobble its insect swarms and fat cotton grasses. More than 180 bird species breed in the Arctic every year and then head south. Bird families include ducks, geese, shore birds, jaegers, gulls, terns, warblers, loons, and swans. Only a few hardy ones reside the year round: gyrfalcon, ptarmigan, raven, the little auk, and the snowy owl.
Snowy owls Are Polar Wanderers
His huge wings — spread as curved fans, each distinct feather backlit by the sun — break his descent in absolute silence. The snowy owl alights on a cliff’s edge with an Arctic hare to feed his hungry brood. The chicks look like scattered, small, dark rocks on the cliff top, some larger than others due to staggered hatching. Their nest is a small depression in the ground with a panoramic view. Would-be predators stand little chance of sneaking up undetected. Normally still as stones, the chicks break pose to beg food from their father, nibbling at his bill and feathers, as the mother takes off to hunt. That’s the life of an owl: a constant search for food.
These ultimate survivors will eat anything and can tough out even the ice pack wrapped in Arctic night. Denver Holt of the Owl Research Institute, discovered this oddity by tracking them with tiny radio transmitters. What can owls find to eat on the ice pack in winter? Holt guesses they, like the Arctic foxes, follow the polar bears and scavenge polar bear leftovers.
A snowy owl chick caught on the tundra near Barrow (Jack Williams, USATODAY.com)
Among the strongest of owls, although not the largest, snowy owls wander all over the Arctic. They range from Ellesmere Island to the southern shores of Hudson Bay and from northern Siberia to the Shetland Islands off the coast of Scotland. They follow food and leave the Arctic only when lemmings disappear. Then, they’ve been sighted as far south as northern United States.
Snowy Owls
- Distribution: in the tundra of Siberia, Scandinavia, Spitsbergen Islands, Novaya Zemlya, Iceland, Shetland Islands, Greenland, Ellesmere Island to Hudson Bay.
- Size: 20 in (51 cm) long, with 55 in (140 cm) wingspan.
- Unique features: Looks like a white speckled barn owl. Staggered hatching results in the last hatching occurring about when the first chick fledges.
- Diet: lemmings, mice, rabbits, ground squirrels, many birds including oystercatchers, Arctic skuas, eider ducks, gulls and buntings, and, occasionally, insects, fish and carrion.
Birds Stay Busy in the Short Summer
In late May to early June, birds swoop into the Arctic, stake out territory, display and sing advertisements for mates and warnings to trespassing males. Late June finds most females sitting on nests, incubating eggs, and trying to look inconspicuous.
Males take off for lagoons remote from prowling Arctic foxes to molt and grow new flight feathers. Flightless and practically helpless while molting, they feed and rest in safe harbors.
Meanwhile, chicks peck shells and a thousand pecks later breathe outside air. By mid July most have hatched and by mid August they’re ready to fly. In late August and early September, they take off south for winter grounds. None too soon either — the tundra and seas start to freeze and snow falls in early September.
Many Birds Are World Travelers
Arctic migrants are a worldly bunch: dunlins take off for China, northern
wheatears for Africa, Arctic terns for Antarctica, and sandpipers for Argentina.
Birds that summer in the Arctic come from all over the world (Arctic Circle)
Some dart over vast stretches of water. The American golden plover — a small bird less than a foot long — logs more than 20,000 miles in a year zipping along at 60 to 100 mph (100 to 160 kph). She takes off from an Arctic coast, perhaps in Alaska, and rips across North America to Newfoundland. She and the flock rest and then take off again: over the Atlantic Ocean and flies without stopping they reach Guyana on the north coast of South America. Here they drop to the ground, exhausted, to recuperate. They take off and fly 2,500 miles (4,000 km) over Amazon jungles to the waving grasses of the sunny Argentine pampas.
Don’t Mess With Musk Oxen
What could be a better defense? Snow and wind buffet their broad shoulders. They face outward — the bulls — with weapons ready, guarding the cows and calves huddled in the center. Grey shapes slip in and out of the blowing snow. One attacks. A bull hooks a curved white horn into the flank, drives broad hoofs down, and tramples the wolf beneath 700 pounds (320 kg) of body mass. If such tactics aren’t enough, bulls charge in mass and drive off the pack.
A small circle of musk ox defending their young. North Slope, Alaska (National Oceanic & Atmospheric Administration)
The defense has worked for a million years. More than 1,000,000 musk oxen roamed the Arctic tundra during the ice age of the Pleistocene Epoch. Then men with guns arrived. The musk oxen stood defenseless against such an enemy. Bulls, cows, and calves were easy shots: just standing there, a motionless closely grouped target. In 1894, an Inuit may have shot the last Alaskan musk ox and thought it was "a bear with horns". By 1900 the musk ox was rare in Canada and non-existent in Alaska.
Definitions
Inuit An Eskimo that lives in the Arctic regions of North America, especially Canada and Greenland. The native peoples of Canada and Greenland generally prefer to be called Inuit and those of Alaska, Eskimo.
Pleistocene Epoch Geological period 1.6 million to 10,000 years ago. During that time, ice covered northern areas and then retreated.
A Little Help From Their Friends.
In May 1930, the U.S. Congress decided to bring musk oxen back to Alaska and appropriated $40,000 for the task. They gave the old U.S. Biological Survey instructions "to acquire a herd of muskoxen for introduction into Alaska with a view to their domestication and utilization in the Territory."
Musk oxen still lived in Greenland, 8,000 miles away. For $40,0000 the United States purchased 34 musk oxen and one-way tickets for them to Alaska. First, though, someone had to catch them. Norwegian sailors got the job. Musk oxen bulls fought them every step of the way. It was brutal. The only way the sailors could rope the calves and yearlings without the bulls killing the sailors was to kill the bulls. "There is much violence in a flock of muskoxen," the leader wrote in his journal.
By the end of August, the expedition captured 19 female and 15 male musk oxen and shipped them to Norway. From there, they crossed the Atlantic by steamer, reaching the Statue of Liberty on Sep. 15, 1930. Eventually, after traveling across the United States by train and to Alaska by ship, they arrived in Alaska in good shape. Now 3,500 of the ice-age creatures wander the Alaskan tundra from the Yukon River delta in the southwest to the Arctic National Wildlife Refuge in the northeast.
Musk ox
- Distribution: on the tundra of Canada, Alaska, Greenland, Norway, Siberia, and some Arctic islands.
- Size: 4 - 5 ft (1.2 - 1.5 m) tall at the shoulder and weighs 500 - 800 lb (230 - 360 kg)
- Unique features: Short, stocky legs, broad hoofs. Related to sheep and goats. Bulls have 2-foot (60 cm) horns: females and young, smaller ones. You can smell the strong musky odor of a bull in rut, a hundred yards (100 m) away. Their musk glands are on their faces. They travel in small herds of 20 to 30.
- Diet: grasses, willow leaves, lichens, and Arctic flowers. They are ruminants, like cows, with a four-part stomach and swallow their food without chewing it. Later, they regurgitate the cud (undigested food) and chew it.
Caribou are Born free
She tosses her head back, antlers glistening in the sun, samples the air, holds her white tail high, and takes off at a fast trot. Her internal clock and belly say it’s time to go. Nights shorten, spring nears, she needs more food. And her unborn calf thumps again. She hurries. The other cows and young of this Alaskan herd (named the Porcupines) begin to move in a line with her. They seek the greenery about to emerge farther north.
Caribou cow starts off. (National Oceanic & Atmospheric Administration NOAA)
Caribou are a variable lot. Some herds move slower than others. Sometimes small groups of animals will break out of the herd and migrate at a slower pace or even stop migrating and take up residence at that place. The leaders change from one migration to the next.
About two million caribou roam the tundra and forests of North America from Alaska to Labrador. Some herds migrate 3,000 miles (5,000 km) a year — farther than any other land animal. Other herds travel shorter distances and some (the woodland caribou) don’t migrate at all or no more than about 40 miles (65 km).
In general, caribou make two major migrations a year: one for food, the other for shelter. In the spring, they seek the lush tundra, greening to the north. Cows head there to drop their calves and bulls follow soon. In the fall, they retreat south to the forests for winter shelter.
During winter, the Porcupine Caribou Herd browses in snowy forests south of the Brooks Range. In April, a cow decides to go north to calve. Other cows follow, moving at a brisk walk, in single file. The bulls trail in a few weeks.
Nobody knows which route they will travel from year to year. They’ll probably use the well-beaten route — swimming rivers and contending with wolves — to calving grounds on the Arctic coast, about 400 miles (645 km) away. But maybe not.
Caribou cows give birth the first week of June, almost simultaneously — the whole herd. About half drop their calves within days and 90 percent within a fortnight of each other.
In late June and early July, the whine of freshly hatched mosquitoes and the buzz of flies fill caribou hearts with dread. They move together in the tens of thousands to the coast, to ice fields, to uplands in the Brooks Range — anywhere to escape the torment. By mid July the herd heads out, east and south, back to the forests to spend the winter.
Caribou, Reindeer Are the Same, but Different
Caribou and reindeer are the same species but they sure act differently. The Sami (Lapps of Scandinavia and eastern Siberia) tamed the reindeer centuries ago. Consequently, reindeer don’t migrate, but they do pull laden sleds.
In the late 1800s, the Reverend Sheldon Jackson brought reindeer from Siberia to the Seward Peninsula of Alaska. In 1937, the U.S. government transferred ownership of the reindeer (now numbering in the hundreds of thousands) to Alaskan Natives.
In the 1990s, times were good. The Inuits were getting $50 a pound for reindeer velvet to cure sexual impotence. Then the price dropped to $10 when Viagra hit the market. Worse, though, were the caribou.
In November 1996, Tom Gray, a reindeer herder, lost 700 reindeer in a single day. Thousands of migrating caribou wandered through the snowy tundra hills where his peaceful herd of 1,100 dwelled about 60 miles (100 km) east of Nome. The old wild urge to migrate overcame more than half of Gray’s herd. The reindeer moved out with the caribou, turning wild.
Caribou lured such numbers from the Steward Peninsula that eight out of 15 Inuit reindeer herders went out of business. Gray keeps his remaining few isolated from the wild ones on a strip of land that juts into Golovin Bay. It’s not much of a buffer, the caribou are only six miles away.
Facts about caribou and reindeer:
- Distribution: reindeer live mostly in Scandinavia and Siberia, some in Alaska. There are currently three large herds of caribou, each about 500,000 animals: the Western Arctic herd in northwest Alaska, the George River herd in northern Quebec, and the Taimyr Peninsula herd in Siberia.
- Size: 3 - 4 ft (1.2 - 1.5 m) tall at the shoulder and weigh 300 - 700 lb (230 - 360 kg)
- Unique features: They live in small bands, five to 100 caribou, or herds of up to 3,000. A healthy caribou can gallop at over 40 mph (65 km/h) and outrun wolves.
- Diet: in winter they eat grasses and lichen. Browse on willow and aspen twigs. In summer, they browse and graze on birch, willow, horsetails, grasses and sedges.
The least you need to know
- The Arctic has only a few species but many animals.
- Tough midget plants survive, rooting in soil that thaws a few inches (centimeters) deep in the summer.
- Plants and animals survive Arctic conditions by adapting.
- Some animals have snowshoe feet, like the Arctic hare.
- Lemmings don’t commit suicide but their population swings set life’s tempo in the Arctic.
- Arctic foxes and snowy owls eat anything and roam far to find it.
- Almost 200 bird species flock to the Arctic each year, some traveling thousands of miles.
- Hunters wiped out the musk oxen in Alaska but the U.S. government restored the herd.
- Caribou and reindeer are the same species but caribou migrate freely, some going farther than any other mammal.