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

hunters.

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.

Caribou

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 

its range.

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

caribou.

U.S. Fish & Wildlife Service

1 800/344 WILD

http://www.fws.gov

August 1998

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.