Caribou are the largest members of the
reindeer family (Rangifer tarandus) and are
native to the arctic and sub-arctic regions of
Siberia, North America and Greenland.
Reindeer, which are traditionally herded in
northern Europe and Eurasia, were
introduced into Alaska in 1892. Although
some herding of reindeer continues in
Alaska today, many of the introduced
reindeer interbred with caribou. The four
caribou subspecies—barren ground,
Peary’s, tundra and woodland—differ
greatly in range, size, coloration, behavior,
food habits and habitat use.
Caribou are a medium-sized member of the
deer family and stand about 31⁄2 feet tall at
the shoulder. Females (cows) can weigh up to
300 pounds, while large males (bulls) are
about twice that size. Most caribou are
medium-brown or gray, but coloration varies
widely from nearly black to almost white.
Their winter coat is somewhat lighter than
their summer coat.
Caribou are the only deer species in which
both males and females have antlers. Their
antlers, which are shed every year, have a
long, sweeping main beam up to five feet
wide. Each side has one or two tines, or
branches, and each tine may have several
points. The larger racks of caribou bulls
are considered trophies by big-game
Caribou have special adaptations that allow
them to survive their harsh arctic
environment. Long legs and broad, flat
hooves help them walk on snow and on soft
ground such as a peat bog. A dense woolly
undercoat overlain by stiff, hollow guard
hairs keeps them warm. Caribou dig for food
using their large, sharp hooves.
The average lifespan of an adult caribou is
eight to ten years. They reach maturity at
about three years. As with most deer
species, male caribou fight each other for a
harem of five to 40 cows. This sparring,
called rutting, occurs in the fall. Injuries in
this natural quest for dominance are rare,
although occasionally the bulls’ antlers lock
together and both animals die.
A single calf is born in the spring. Unlike
most deer, caribou young do not have spots.
They are able to walk within two hours of
birth and are weaned gradually over several
months. After calves are born, females with
newborns gather into “nursery bands” and
separate from the rest of the herd.
Gradually, the bulls and barren cows rejoin
the calving cows at the calving grounds.
These larger groups of caribou offer some
protection for the calves from predators
such as wolves, bears and lynx.
Caribou feed on sedges, grasses, fungi,
lichens, mosses, and the leaves and twigs of
woody plants such as willows and birches.
Although some herds stay on the cold tundra
all year, most caribou have distinct summer
and winter ranges. The large northern herds
migrate over long distances, frequently
crossing large, swift-running streams and
rivers. Consequently, even caribou young
are extremely strong swimmers.
Insect bites are a particular nuisance for
caribou. When mosquitoes are numerous,
a caribou may lose up to half a pint of
blood a day. In coastal areas, they seek
temporary relief by submerging
themselves in water. They may seek
windy hilltops, dry, rocky slopes, or
snowfields if they do not have access to
a coastal area. Barren ground caribou
have been known to stampede in attempts
to escape the ravages of mosquitoes,
warble flies or nostril flies.
Rangifer tarandus caribou
Adult male caribou can weigh up to 600
pounds. Females, generally not as large,
can weigh up to 300 pounds.
U.S. Fish & Wildlife Service
Caribou were once essential to the survival
and livelihood of native peoples of the Arctic.
Natives used caribou meat, milk and organs
for food. Hides provided material for
clothing and shelter, and bones, antlers, and
sinews were used to make tools, tableware,
and handicrafts. However, though caribou
remain a subsistence food resource, other
uses have declined as native populations
have become more technologically advanced.
Though caribou in North America were once
found as far south as Lake Superior, today
they are completely absent in New
Brunswick, Nova Scotia, Maine and
Minnesota, mainly due to changes in plant
growth since the last glaciers receded 10,000
years ago. Remnant caribou populations in
these areas were susceptible to the
encroachment of European settlers and
subsequent changes in the habitat brought
about by logging, farming and fire
suppression. The early settlers also hunted
caribou heavily for food.
Only one population of caribou is left in the
lower 48 states—the Selkirk Mountain herd
which ranges from Canada into northern
Idaho. Outside Alaska, this herd of woodland
caribou is the last of its kind in the United
States. In 1983, the U.S. Fish and Wildlife
Service placed this population on the
endangered species list, giving it protection
under federal law. Endangered status
means the woodland caribou is considered
in danger of extinction within that part of
Canada and the State of Idaho cooperatively
manage the Selkirk Mountain herd through
monitoring and reintroduction of more
woodland caribou to enhance the population.
In Alaska, the U.S. Fish and Wildlife
Service, through its Arctic National Wildlife
Refuge, protects large portions of the range
of the Porcupine caribou herd, in particular
the herd’s sensitive calving grounds.
Although the Porcupine herd is not
considered endangered, in 1987, the United
States and Canada finalized a formal
agreement for the conservation and
management of this group of majestic
U.S. Fish & Wildlife Service
1 800/344 WILD
Caribou currently range throughout arctic
and sub-arctic areas of Siberia, Greenland
and North America. The U.S. population is
limited to Alaska.
Caribou are adept climbers, ascending steep
slopes and traversing glacial snow fields.
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