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by C. A. Linder
The Arctic is one of the most inhospitable places on earth. The few
creatures that live here year-round have adapted to their unique environment
in many interesting ways. I have included brief descriptions of the
most charismatic Arctic animals, both land and marine. For more detailed
information, I recommend E. C. Pielou's A Naturalist's Guide to
the Arctic and Tony Soper's The Arctic - A Guide to Coastal
Birds - Overview
| Immature black-legged
kittiwakes dive for cod in the icebreaker's turbulent wake.
photo © C. A. Linder, WHOI
There are eleven year-round species of birds which are Arctic residents:
gyrfalcon, raven, rock and willow ptarmigans, snowy owl, redpoll,
Ross's and ivory gulls, thick-billed murre, dovekie, and black guillemot.
In the arctic summer months, when
food is plentiful and the sun never sets, the
Arctic is teeming with bird life (an estimated 16 million individuals
in the Barents Sea alone!). It is the lack of food, rather than the
cold temperatures, which drives the majority of birds south for the
winter. In winter, ponds and mud flats freeze over and the sea ice
conceals much of the ocean's surface. The meat-eating bird species
survive the winter by supplementing their diet of fish, birds, lemmings,
and voles with carrion from polar bear kills. Vegetarian birds such
as ptarmigans and redpoll eat seeds and buds of dwarf willows under
the snow. As the harsh winter gives way to spring, 183 species of
birds engage in breeding in the Arctic, taking advantage of the explosion
of life that near-constant sunlight brings.
Mammals - Overview
The Arctic is home to a number of land and marine mammals. They have
all developed adaptations to cope with their unique environment. Large
land mammals such as muskoxen, caribou, and polar bear grow thick
winter coats to protect them from the intense cold. Tiny voles and
lemmings dig tunnels in the snow to avoid the numbing above-ground
temperatures. In addition to resisting the cold, mammals also need
to find enough food to sustain them through the winter. Herbivores
such as muskoxen lay on extra fat reserves during the summer. Caribou
(and possibly muskoxen) also adapt to winter conditions by undergoing
a seasonal weight loss, which is gained back in the summer. Carnivores,
in particular polar bears, take advantage of the sea ice by using
it as a hunting ground. Arctic foxes follow polar bears far out onto
the ice, eating the remains of polar bear kills (which never spoil
thanks to the subfreezing temperatures).
Polar Bear (Ursus maritimus)
| A polar bear scrambles
onto an ice floe in the Beaufort Sea.
photo © C. A. Linder, WHOI
The mighty polar bear is the undisputed king of Arctic predators.
Weighing up to 1100 pounds, the polar bear is perfectly adapted to
a life on the pack ice (some biologists consider polar bears "marine
mammals"). Its white coat aids in both camouflage (from potential
prey) and heat retention. The specially adapted hairs are hollow,
allowing the sun's energy to penetrate to the black skin beneath.
Massive paws serve as both paddles for swimming and snowshoes for
crossing thin ice. Polar bears primarily feed on ringed seals, but
when seal meat is scarce they survive on fish, seabirds, and scraps.
In summer, polar bears will eat berries and vegetation much like their
cousin the grizzly. Most bears live within 200 to 300 km of the shoreline,
since the broken ice around the coast is the best seal habitat. Since
seals do not hibernate, neither do polar bears (there is one exception
- pregnant females hibernate for a few months immediately before giving
birth). The world population of polar bears has recently been healthy,
estimated at 25,000 in 1991, with about 15,000 living in the Canadian
Muskox (Ovibos moschatus)
The muskox, distinguished by its long, curved horns and thick coat,
resembles a relic from the Ice Age. Adults resemble bison in appearance,
but are actually from the family Bovidae, which includes goats and
sheep. They are supremely adapted to a life on the
tundra, and do not seek shelter even in the worst winter blizzards.
While their bodies are designed to retain
as much heat as possible, what keeps them really warm is their thick
coat. It has two layers with different types of hair. The outer layer
is composed of long airtight guard hairs which nearly brush the ground.
The inner layer is made of very fine wool, called "qiviut" by the
Inuit. 30 grams of this makes enough yarn for a skirt. In winter
the oxen feed on hill ridges, which although very cold, are kept snow-free
by the strong winds.
Caribou or Reindeer (Rangifer tarandus)
Caribou are the most numerous large mammal of the arctic tundra, and
are similar to the reindeer of Russia and northern Europe. Caribou
are unique in the deer family in that both sexes bear antlers. One
of the wonders of the North American Arctic is the caribou migration.
In spring the caribou head north to the tundra, in several different
herds of up to 10,000 animals, to give birth to their calves. This
provides them safety from their main predator, the wolf, which rarely
penetrates this far north. The caribou are known for wide fluctuations
in their population, due to factors including overgrazing of their
summer pastures, forest fires that destroy vital lichens, abnormal
weather conditions (food plants covered by snow or floods), or disruption
and hunting by humans. Caribou meat is the second main food source
for the Inuit (after seal); as such, the maintenance of the caribou
herds is crucially important for the local human population.
Arctic Fox (Alopex lagopus)
This subspecies of the fox grows differs from temperate foxes by its
shorter muzzle and ears. Its legs and tail are likewise shorter --
all of these factors combine to improve heat retention. The arctic
fox's winter coat can be either white or bluish-gray, changing back
to grayish-brown in summer. Unless they are breeding, arctic foxes
are solitary, wandering great distances in search of prey. Like all
foxes, its scavenging ability helps it to survive: in winter it survives
on scraps, small prey and leftovers from polar bear kills, as the
bears eat only the blubber of the ringed seal, their preferred prey.
In summer when the pack ice melts the foxes come ashore to breed.
They make dens along the arctic coasts, where they prey on nests of
seabirds and waterfowl. Their fur has been a valued commodity for
the Inuit; in areas with high fox populations the Inuit gain income
from arctic fox trapping.
Wolf (Canis lupus)
Wolves inhabiting the arctic region are of the same species as the
timber wolf, which was at one time found throughout Northern Europe,
North America and Asia. Over past centuries they have been hunted
to near extinction and persecuted as predators of livestock and reputed
man-eaters. The latter is largely myth; wolves rarely attack people
where the species is still found, mostly in Canada, Northern Russia,
Eastern Europe and parts of Scandinavia. Living in Arctic or Northern
forests and tundra, and straying further into the tundra when hunting
in packs, they prey on many arctic species, including deer, oxen,
arctic hare and small rodents; they will also eat fruit. They are
intelligent hunters, often working together to bring down large prey.
However, they are also scavengers, eating leftover kills by other
large species such as polar bear. Arctic wolves are almost always
light in color, ranging from pure white to light gray.
Arctic Hare (Lepus arcticus)
The arctic hare is the largest of all hares, weighing up to 11 lbs.
Like the arctic fox, this hare has a luxuriant, camouflaged white
coat. Unlike the fox, it is white all year round. Hares are born ready
for survival, with open eyes and a full coat, and can be running soon
after birth. Its ears are smaller than those found in the brown hares
of temperate climates, aiding in reducing heat loss. It lives outside
all year round, surviving by digging beneath the snow to reach plants
hidden below the surface, and shelters in a burrow in the snow. It
is an important prey species for arctic foxes, wolves, eagles, and
Mouse, lemming, and vole family (Muridae)
Seven members of this family live in the Arctic -- 3 species of lemmings
and 4 species of voles. They are similar to temperate mice except
for their shorter ears/tails and stouter bodies. Lemmings are at the
bottom of numerous arctic food chains, and their population is critical
to the populations of their predators. Population explosions, followed
by crashes, occur every four years unless interrupted by climatic
Walrus (Odobenus rosmarus)
Walruses are divided into two subspecies - Atlantic and Pacific. Pacific
walruses are much larger, weighing up to 1.3 tons compared to the
.75 tons of the Atlantic variety. They live in shallow, icy seas,
using the floes for mating and birthing. Walruses are bottom feeders,
using their whiskers to find clams and other bivalves in shallow waters.
Both males and females grow tusks from their upper jaws. Walruses
are extremely social, hauling out on the ice in large herds, and walrus
mothers are extremely protective of their young.
Seals (family Phocidae)
Five types of seals spend at least some time in arctic waters: bearded
seal, ringed seal, harp seal, hooded seal, and harbor seal. Bearded
and ringed seals spend their entire lives in the Arctic. Hooded and
harp seals spend summers in the Arctic, and harbor seals only occasionally
venture north into the Arctic. The bearded seal (Erignathus barbatus)
is the largest arctic seal, and bears the closest similarity to walrus.
They are bottom feeders and have prominent whiskers. The ringed seal
(Phoca hispida) is the smallest arctic seal, and most common.
They feed on shrimp, krill, and other small crustaceans. The harp
seal (Phoca groenlandica) is a deeper diving seal which feeds
on small fish. Juvenile harp seals are prized for their coat, which
has led to bitter enmity between sealers and environmentalists. Hooded
seals (Cystophora cristata) lead similar lives to harp seals,
but can be distinguished by their long proboscis, which can be inflated
to create a "hood".
Resident Arctic Whales (Bowhead Whales, Belugas and Narwhals)
Three whales are truly arctic species, never venturing south from
the icy northern waters. The bowhead whale (Balaena mysticetus)
is a baleen whale, feeding on krill and small fish by ingesting large
quantities of water and trapping their prey in huge baleen plates
in their mouths as the water is expelled. Bowhead whales are quite
large, commonly reaching 60 feet in length. They have a unique V-shaped
spout, which can be seen at a great distance. The Inuit (Eskimos)
are allowed by the USA to hunt a limited number of bowhead whales
a year. Commercial whaling nearly exterminated the bowhead, and their
population has not recovered. By 1991 the bowhead population was down
to about 7,800 animals from 20,000 in the mid-nineteenth century.
It is thought that limited Inuit hunting will not threaten numbers
further. The Inuit traditionally relied upon the spring whale hunt
to supply most of their food needs. Muktuk or whale-skin
is a delicacy, high in Vitamin C, and of great nutritional value in
a climate where fruit and vegetables cannot easily be grown. If they
are prevented from hunting at all, the Inuit will lose a central part
of their culture; it forms the basis of their rituals and customs.
However, some environmentalists feel that now that the global economy
provides imported or manufactured foodstuffs, cultural traditions
should give way to wider ecological concerns. To hear some noises that bowheads make,
visit this Cornell University website.
The narwhal and beluga are toothed whales of the family Monodontidae.
The narwhal (Monodon monoceros) is about 20 feet long and
is found only in the eastern North American Arctic. Only males have
the characteristic tusk, which is really just a long single tooth.
Scientists are still unsure about the function of the tusk. Narwhals
are social and talkative, using a complex series of clicks and chirps
to communicate. The beluga (Delphinapterus leucas) is similar
in size to the narwhal, but very different in appearance. The adults
are pure white (young are gray) and their curved lips make it look
like they are continually smiling. The inhabit much shallower waters
than the narwhal, but are likewise extremely talkative, earning them
the nickname "sea canary".
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