Reindeer Facts and FAQ's

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Basic Biology

Reindeer (Rangifer tarandus) are semi-domesticated caribou. Although similar, there are fundamental differences between reindeer and their wild cousins, caribou. Reindeer are shorter and stouter. Reindeer bulls are smaller than caribou bulls, but cows may weigh the same as caribou cows. Coloration differences may be too subtle to notice between many reindeer and caribou, however, reindeer tend to be lighter with occasional pinto or white haircoats. The nose bridge, or face, of reindeer are flatter than caribou. Reindeer tend to stay in more cohesive groups. When herded or chased they tend to run in a tight group, whereas, caribou are often scattered. These traits are the result of domestication. It is believed they have been domesticated in Eurasia for at least 7,000 years, which is longer than the horse (Edwards, 1994). In Eurasia reindeer are classified as either domesticated or wild. Only in North America are “wild reindeer” called caribou.

 Phylum-Chordata (backbone w/ spinal chord)
  Class-Mammalia (milk producing)
   Subclass-Ungulata (hooved)
    Order-Artiodactyla (even-toed)
     SubOrder-Ruminantia (true ruminant)
      Family-Cervidae (deer)
        Species-tarandus (w/ about five Holarctic subspecies)

Female reindeer typically reach reproductive maturity as yearlings and may stay productive up until 15 years of age. Some female calves on the Seward Peninsula conceive at five months of age and calve as yearlings. Bulls usually don’t breed until they’re three years old. Their life expectancy is about eight years, usually ending as a result of their final breeding attempt. Breeding takes place in August and September with calving peaking around April 24th. This is a one month difference for breeding and calving between reindeer and caribou (and Scandinavian reindeer) Alaska Department of Fish and Game's Wildlife Notebook Series). However, reindeer and caribou can interbreed. Most likely, breeding would be between a male caribou and female reindeer, because caribou are usually dominant.

Reindeer and caribou are the only deer (Cervidae) where males, females, and calves produce antlers. Substantial growth of calf and female antler can be obtained with good nutrition. Some females can grow small shovels (eye-guards), normally grown only by bulls. Like other deer, reindeer shed their antlers annually. Bulls drop their antlers by January, and pregnant cows and calves retain theirs until spring. Normally, pregnant cows retain their antlers a week or so after calving for advantage over food resources.  New antler growth in the spring and summer is nourished by a highly vascular covering called velvet which is shed in August. Bull antler hardens (ossifies) in June and cow antler in July. The primary function of antler is for gaining social dominance. There is a demand in Asia (China, Korea) for antler just before it ossifies into hard bone. It is processed in different ways for use as health aids.

Adaptations For Life in the Arctic

Reindeer hair is extremely dense. The outer coat of long, hollow guard hairs are at a density of 5,000/ A fine “wooly” hair at 13,000/ as an undercoat makes for an efficient air trap. This thick coat inhibits radiation and allows them to lay on snow without melting it and getting wet. Facial hair extends down to their lips protecting the muzzle when grazing in snow. Reindeer don’t get frost build-up from their breath. Bone and cartilage in their nostrils are designed like a “rolled-scroll.” This increases the surface area inside so that blood can warm the cool incoming air. Heat is retained and moisture condensed and retained from expired air. The hollow guard hair provides bouyancy facilitating their swimming ability. Their multi-colored coat allows for concealment, an advantage for free-ranging reindeer. However, adaptations such as preventing radiation and lack of sweat glands for heat conservation in winter may cause stress in warm weather. In summer they shed their guard hair exposing their dark, soft undercoat.

Reindeer hoofs are large relative to their body. This load factor and wide splaying of their hoofs, acting like snowshoes, helps them to walk on snow. The hoofs are concave and do not have pads. The edges may act as blades and hair extending under the hoofs help when walking on ice. The shovel-like design also helps with swimming and digging for forage (cratering). Their hoofs and gait enable them to travel across tundra efficiently. They have a relatively high-stepping gait combined with a trot like a cross between a horse and camel. Because they are not as long-legged as caribou, it is thought that when reindeer mingle with caribou they have a higher predation rate because they may be slower than caribou.

Reindeer, like all Cervids and Bovids, are ruminants. They are classified as a “concentrate selector” to intermediate forager which means they select higher quality forage, whereas, cattle and bison are considered generalist grazers because they eat large amounts of lower quality forage (Hofmann 1988). For instance, when given longstem hay, reindeer will eat only the more palatable leafy parts. Free-ranging reindeer search for emerging buds, leaves and flowers of sedges and dig for rhizomes in the spring, followed by willow leaves, forbs, and mushrooms as they emerge in early summer. Reindeer physiology is specialized to eat and digest lichen (sometimes called reindeer moss) as an energy source in winter. Lichen is produced by a symbiotic relationship between algae and fungi.(Click to see free-ranging Reindeer diet graph)

Captive reindeer must be fed a balanced diet of commercial grains, forage and supplements. A special adaptation of northern ungulates is the seasonality in their appetite, metabolism and growth rates. Reindeer decrease their food intake and lose weight in the winter and increase their appetite and growth in spring and summer. This cycle is maintained not only for free-ranging reindeer, but also when offered ad-lib feed (shown in graph below). Also, they decrease their activity in winter to conserve reserves. Reindeer prefer snow over water in winter. The lack of minerals in snow and small amount in lichen minimize the requirement for water. Also, there is a lower loss of body heat to melt snow than to search for and warm copious amounts of water.

Winter conditions may still exist when calves are born. Reindeer milk is extremely high in protein and fat. Many organs of reindeer are relatively larger than many domestic animals for increased growth rate. These two factors facilitate survival, especially for free-ranging reindeer. Adults, particularly cows, are nutritionaly stressed during springtime. They are known to eat rodents, eggs, placenta and chew on antler to attain limited nutrients.


CURRENT RATION (18% crude protein Fish Meal and Barley base) Per Ton:
Barley (rolled) = 1,544 Lbs.
Brome hay (chopped) = 200
Fish Meal = 57
Molasses = 81
Corn oil = 30
Limestone = 16.6
DiCal = 5.0
Urea = 12.4
Vitamin Premix = 58
(Barley = 81.6; ADM-blue label vitamin/ mineral mix = 7.65; plain salt = 7.65; and corn oil = 4)

Note: due to digestive dynamics with concentrate diets this ration should be offered slowly over a period of two weeks or more. Contact us for other diets and information.

We supplement the diet with long-stem hay about every five days. This semi-fresh forage is something for our reindeer to nibble on to break the monotony of their concentrate ration, especially in winter. It may also help maintain a healthy population of microbes that produce enzymes to digest grasses. Remember, the leafy parts only are palatable to reindeer, and hay alone is not sufficient nutrition for reindeer.


    Seward Peninsula, Alaska


    Captive Reindeer(Alaska)


Both male and female reindeer grow antlers. Although adult males grow the largest racks, adult females can have some very impressive antlers making it difficult or impossible to distinguish the sex based on antlers alone. Bulls generally shed their antlers in winter between December and January. Castrated males(steers) and non-pregnant females will shed their antlers between February and April. Pregnant females will retain their antlers until after they have their calves in late April and May.

Causes of Calf Mortality

   Based on 89 calves observed April through November 1991 and 1992 on the Seward Peninsula, Alaska (Chetkiewicz, 1993)

Literature Cited

Chetkiewicz, C.B. 1993. Reindeer (Rangifer Tarandus) calf productivity and survival on the Seward Peninsula. Unpublished M.S. Thesis. University of Alaska Fairbanks.

Edwards, E.H., 1994, IN: The Encyclopedia of the Horse, Dorling Kindersley, pub., pp. 28-30.

Hofmann, R.R. 1988. Anatomy of the gastrointestinal tract. In: The Ruminant
Animal. D.C. Church, ed. Prentice-Hall, Englewood Cliffs, N.J. P. 14.


Alaska Department of Fish and Game's Wildlife Notebook Series

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