Reindeer and caribou are the same animal (“Rangifer tarandus”). The main difference is that reindeer are domesticated and found in Scandinavia and Siberia and caribou are wild and found in North America. There are two main kinds of caribou: woodland caribou and barren ground caribou (about a third smaller than woodlands caribou). Mountain reindeer are found in the ranges of Russia and northern Europe. [Source: "Man on Earth" by John Reader, Perenial Library, Harper and Row, "Nomads" 99-108]

Male reindeer and caribou are called bulls (or stags in some places). Females are called cows and youngsters, calves. Males often have whites clumps of hair that hang from their throats. Caribou and reindeer live primarily in the Arctic tundra, where the temperature average 23 degrees F throughout the year and can drop as low -76 degrees F. They are thought to have originated in North America. Up until 12,000 years ago they shared the Arctic tundra with wooly mammoths and mastodons.

Caribou and reindeer are the world's most widely distributed large land animals. As of the 1990s there were four million wild caribous in 200 herds: 102 in North America, 55 in Europe, 24 in Asia and 3 introduced herds on South Georgia Island in the southern Atlantic. Three fourths of these animals occur in just nine herds (eight in North America and one in Russia). In Alaska, there is a single herd with 600,000 caribou.

Woodlands caribou used to live as far south as Minnesota and Maine in the United States. Attempts to reintroduce them to these places have been thwarted in some places by a snail-bourne meningeal worm carried by white tail deer, who roam all over the United States. This parasite is relatively harmless to them but eats at the brain of caribou, moose, elk and other kinds of deer.

Deer Family

Reindeer are members of the 60-member deer family, which includes elk. The largest deer are moose, which can weigh nearly a ton, and the smallest is the Chilean pudu, which is not much larger than a rabbit. Deer belong to the family “Cervidae”, which is part of the order “Artiodactyla” (even-toed hoofed mammals). “Cervidae” are similar to “Bovidae” (cattle, antelopes, sheep and goat) in that they chew the cud but differ in that have solid horns that are shed periodically (“Bovidae” have hollow ones).

Deer have a lifespan of around 10 years. A male deer is called a buck or stag. A female is called a doe. Young are called fawns. A group is called a herd. Deer don't hibernate and sometimes group together to stay warm. Particularly cold winters sometimes kill deer outright, mainly by robbing them of food, especially when a hard layer of ice and snow keeps them from getting at food.

The top speed of a deer is around 30 miles per hour. Some deer can reach speeds of 40mph for short bursts and gallop for three or four hours at a speed of 25mph. Some deer can vertically jump 25 feet. The tracks of stags are bigger and broader than those of does. They have a more swaggering walk.

Deer are hunted by humans and are prey of large carnivores such as tigers, cougars, wolves and occasionally bears. Deer meat is called venison. People have made buckskin jackets, moccasins and other items of clothing from deer hide. Reindeer outer fur is coarse and bulky. It traps air that keeps the warm. Garments made with reindeer fur keep people warm in the same way.

Reindeer Characteristics

Reindeer and caribou are larger than most deers, including white tailed deer found in the U.S., and smaller than elks and have heavier bodies and shorter and thicker legs in relation to their body compared to deer. Reindeer are covered with mottled gray, brown and white fur. Their fur is generally grayish brown on their backs and white on their undersides. Their muzzle is hairy, broad and cowlike.

Reindeer reach full size at about four or five years of age. A large male weighs around 140 kilograms and stand around 1½ meters at the shoulder. The largest caribou weigh up to 250 kilograms. The smallest caribou are generally found in the harshest habitats.

Reindeer can sleep comfortably in temperatures as low as -45 degrees C and survive temperatures as low as -58 degrees F. Keeping them warm is a five centimeter-thick coat of fur with 13,000 hairs per square inch. During the summer they shed their fur and look moth-eaten. Molting reindeer drop so much fur they look like swamp trees with dangling moss.

Deer, cattle, sheep, goats, yaks, buffalo, antelopes, giraffes, and their relatives are ruminants — cud-chewing mammals that have a distinctive digestive system designed to obtain nutrients from large amounts of nutrient-poor grass. Ruminants evolved about 20 million years ago in North America and migrated from there to Europe and Asia and to a lesser extent South America, where they never became widespread.

Reindeer Legs and Hooves

A reindeer can reach speeds of 50mph (compared to 70 mph for a cheetah and 27.9 mph for the world's fastest human) for short bursts and cruise for long periods of time at 25 mph. When they move, caribou make a unique clicking noise that is caused by the slipping of their tendons over the their ankle bones.

Reindeer have large splayed hooves with unique dew claws (appendages that extend out like legs on a tripod) that not only enable reindeer to travel swiftly across the top of deep, soft snow they also are good for swimming and digging up lichen under a thick snow cover.

The hooves are cleft like a deer's but leave an imprint that is round like a cow's. In the center of the hoof is a spongy pad that expands in the summer and shrinks in the winter and is covered with insulating hair.

Reindeer have an high-stepping gait when they run. The can outrun bears and wolves. Caribou and reindeer are also good swimmers. They have been seen swimming in the open sea in 20 foot waves and through rapids in spring-swollen rivers.

Reindeer Antlers

Both male and female reindeer have antlers that are covered with velvet that provide nourishment for growing antlers. Reindeer antlers feel soft. The racks of large males can reach a meter and a half in length. Every year in September reindeer lose their antlers, but before they do rub the velvet off against trees, revealing red antlers, colored by the animals blood.

Reindeer loose their antlers for four months in the autumn and the winter as a result of sex hormones that cause bone at the base of the antler to be reabsorbed. In the spring the animals grow a new pair of velvet-covered antlers. Only reindeer that have been castrated keep their antlers through the winter.

Female reindeer are the only members of the deer family with antlers and they are not adverse to using them against males competing for scarce lichen patches in the wintertime. After the population of reindeer on an uninhabited island off of Alaska crashed from 6,000 to 42 as a result of overgrazing only one of the survivors was a male.

Many deer annually grow new antlers in the spring and shed their old ones in the fall. The antlers of some species are covered by "velvet" (soft skin laced with blood vessels and covered with fine hair), which provided the antlers with calcium and other nutrients from the body. The antlers reach full growth and peak hardness in the early fall. After this the blood supply to the velvet is cut off. The velvet is rubbed off on bushes and trees in August after the summer.

Among deer, antlers are a kind of symbol of strength and virility intended to impress females and intimidate rivals. They are used by males to battle one another in the rutting (mating season). After the rutting season is over in the fall, the antlers fall off. Males usually grow spike like antlers when they are two and develop a full rack when they are full grown are age six.

Reindeer Behavior and Feeding

Caribou and reindeer spend most of their time grazing. They often snort and cough a lot because their nasal passages are filled with a fist-size ball of maggots.

Caribou are very tame and relatively easy for people to approach. It is not uncommon for tourists to approach a caribou within ten meters, something a deer would never let them do. This is probably one reason why reindeer have been relatively easy to domesticate and hunt. Some scientist attribute their tameness to curiosity.

Reindeer eat a lot in the late summer to build up enough body fat to last the winter and fatten up at an astonishing rate in a short time. Most of their summertime diet consists of grasses, sedges (protein-rich plants), leaves and woody plants that grow rapidly in the brief Arctic summer. During winter about 60 percent of a reindeer's diet is made up of lichens. Lichens are a high-energy food, which are 90 percent carbohydrates, but even so a reindeer has to consume eight kilograms of lichens a day to maintains it body weight. Fish are often fed to domesticated reindeer, which have a fondness for dried fish.

Reindeer can store food and go long period without food but still they have their limits. During the wintertime reindeer spend about ten hours a day foraging for lichen. They can smell the lichens under the snow. They dig and paw away at the snow with their hooves to reach the lichens. Reindeer normally forage through soft snow. Reindeer begin starving when ice or hard snow covers the lichens they can’t break through the ice with their hooves.

A single reindeer can consume up to 12 kilograms of lichens a day. Lichens take as long as 30 years to grow back after they have been consumed and scientist estimate that each reindeer needs at least 25 acres of lichen pasture to ensure survival. This is one reason why reindeer and caribou migrate. Reindeer depend on old growth forests and stable tundra conditions to produce lichens.

Reindeer Mating and Offspring

Males and females mate and males battle one another with clashing and locking antlers during the autumn rutting season. Sometimes bulls become so preoccupied with fighting, courting and mating they don't eat and lose up to one forth of their weight. Dominant males usually mate with several females. They mount from behind like horses and elephant and most mammals do. Young bull sometimes attend senior bulls like proteges and a mentor.

Among most deer, Normally-placid bucks become fierce warriors during the rutting (mating season). Their eyes become bloodshot, their necks puff out and they charge any threat with antlers down. Battling bucks run head on into one another with their antlers and keep charging until one backs off. Sometimes two bucks become locked up and die together.

Female reindeer are pregnant for seven and half months before giving birth in the spring. A calf, although weaned by early autumn, stays by its mother's side through the winter to help dig up lichen. After nursing a calf through the summers females are often extremely thin.

Calves can stand up minutes after birth. Within 24 hours their legs are strong enough to run. After a week they can keep up with their mothers. After three weeks they can outrun a bear. Reindeer calves are vulnerable to attacks from bears, wolves and golden eagles. It is necessary for them to develop quickly to escape predators, namely wolves.

Reindeer Migration

Reindeer spend the winter at lowland tundra feeding grounds rich in lichens. During the spring they head for the fawning grounds on the flowering tundra. During the summer they escape from clouds of mosquitos and hordes of biting black flies in the lowlands and head for feeding grounds in the highlands and forests that are rich in grasses and other vegetation.

Caribou follow age-old migration routes across rivers and around mountains to calving grounds and grazing areas. They march through deep snow, swampy bogs and spongy tundra and often swim through ice cold water. In Alaska, a single herd of 600,000 caribou makes an annual migration following ancient paths that have been used by hundreds of generations. Some of the trails are 10 to 20 centimeters deep and filled with caribous dung and bones of caribou scattered here and there.

Domesticated reindeer spend most of their time roaming free and foraging for food. They and their human herders follow routes that are not all that different from routes they would follow if they were wild.

Predators and Other Problems Faced By Reindeer

Caribou have to deal with predators such as wolves and huge clouds of insects. Newborn calves are easy prey for wolves, brown bears and other predators. Calving grounds are usually in areas with high visibility.

Reindeer calves only have a 50-50 chance of survival. They are vulnerable to predators such as foxes, wolverines, lynxes and eagles, not to mention disease and bad weather. Mature reindeer are sometimes victimized by brain worms or a layer of ice underneath the snow that prevents them from eating lichens which nourish them during the winter. An estimated 10,000 reindeer died in the Chukchi peninsula in northeast in December, 1996 after a period of warm weather and heavy rains was followed by -40 degrees F temperature that produced a layer of ice over grazing lands that made impossible for the animals to feed.

Reindeer are tormented by mosquitos. They are particularly vulnerable when they shed their winter coats. Sometimes mosquitos swarm around a calf and draw so much blood the young animal weakens and dies. Reindeer are plagued by more than 20 different parasites including warbles flies and tongue worms. Stampedes sometimes occur when herds are attacked by swarms of mosquitos and biting flies.

Wolf Attack of a Caribou

Wolves are the main natural predators of reindeer and caribou. Describing an unsuccessful attack by a wolf on a herd of caribou, Arctic researcher David Mech wrote in National Geographic,"The herd, sensing the wolf, was drown together as is by some giant biological magnet. The tightly pressed group flowed quickly forward...The white wolf made its decision. Instantly it sprang forward. While stragglers gravitated toward the herd, the wolf began closing the 200-yard gap." [Source: David Mech, National Geographic, October 1977]

"As the wolf pressed close, the caribous increased their speed. Straight toward them the white wolf sped, with legs alternately stretching out then pulling together in 15-foot bounds...The chase covered a quarter of a mile, and the wolf tried its best. Still the hunter was unable to come closer than about 200 feet of its intended prey...Less than a minute after the chase had begun, it was over."

Historically wolves have fed on the weak, old and infirm and the conventional wisdom was that this helped the reindeer population by ensuring the strongest produced offspring and the herd as whole didn't overglaze the land. With most of the wolves in Scandinavia now gone the primary controlling agent of the reindeer herds are the Lapps.

It is somewhat of a myth that the health of deer populations depend on wolves to cull weak and diseased animals. Studies show that the size and health of deer population is related to snow depth, cold and the availability of food, not wolves. One biologist told National Geographic, "Our data shows that wolves take mainly the youngest deer—those less than a year of age. Old, weak animals are the second most common targets...The herds can handle it" because deer reproduce a lot.

Image Sources:

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.

Last updated May 2016

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