Known as caribou in North America, the reindeer (Rangifer tarandus) is a charismatic and hardy species that inhabits the northern reaches of the planet (3) (4). While the reindeer may occur as a number of different subspecies throughout its range, all are superbly adapted to a life in the extreme conditions of the north (2) (4).
The reindeer’s coat is made up of a thick, woolly under layer, and an overcoat of stiff, tubular hairs which trap a layer of insulating air (2) (3) (4). Although the colour of the coat can vary with location from almost black to pure white, it is generally brown to grey on the upperparts, and pale to white on the underparts, inner legs and rump (2) (5). The face is typically dark, and the male reindeer develops a mane of long, lighter coloured hairs along the underside of its neck (5). During the winter months, the coat of the reindeer tends to be paler (2).
The ears of the reindeer are relatively short and rounded, and the tail is short and furry (3) (5). Inside the long muzzle there is a large surface area over which incoming air can be warmed, and moisture can be extracted from exhaled air to conserve water (3) (4).
Another of the reindeer’s superb adaptations is its large, flat hooves, which act as snow shoes in the winter, and provide stability over soft ground during the summer (2) (3) (6). During autumn and winter, the hooves harden and develop sharp edges which is useful for breaking through snow and ice when searching for food (3). Hair between the toes of the hooves prevents snow from clogging them up (7).
A striking feature of the reindeer is the long, sweeping antlers that are re-grown each year. These vary greatly in shape between reindeer, but generally curve back and then forwards from the head, with a forward-projecting section which may be shovel-like in appearance (2) (5) (6). Unlike horns which grow from the base, antlers grow from the tip, rather like the branch of a tree (4).
Reindeer are the only deer species where both the male and the female possess antlers, although the antlers of the female are much smaller and simpler (2) (5). The female reindeer also tends to be smaller and more slender than the male (3). Unlike many other deer species, the coat of a young reindeer lacks spots when it is born (6).
A variety of vocalisations are produced by the reindeer, including the snort given by an adult when alarmed, the bawling cries of a young reindeer and the roars made the adult male reindeer during the breeding season (2).
Reindeer taxonomy is complex, with a number subspecies suggested based on genetics, morphological observations and the location of particular groups (3) (8). Generally, the following subspecies are recognised in the literature, although these may be subject to change: Eurasian subspecies include the Eurasian tundra reindeer (Rangifer tarandus tarandus) and the Eurasian forest reindeer (Rangifer tarandus fennicus). The Svalbard reindeer (Rangifer tarandus platyrhynchus) and Peary caribou (Rangifer tarandus pearyi) inhabit high Arctic islands (4).
In North America, the reindeer is commonly split into the woodland caribou (Rangifer tarandus caribou), Alaskan or Grant’s caribou (Rangifer tarandus granti) and the barren ground caribou (Rangifer tarandus groenlandicus) (3) (4).
- Also known as
- Caribou, Peary caribou.
- Head-body length: 120 - 220 cm (2)
- Shoulder height: 87 - 140 cm (2)
- Male antler length: 52 - 130 cm (2)
- Female antler length: 23 - 50 cm (2)
- 60 - 318 kg (2)
A highly gregarious species, the reindeer can be found in herds of up to half a million animals (1) (2). These herds are usually made up of smaller, single-sex groups which band together during the annual spring and autumn migration. Most reindeer populations undertake seasonal migrations, with the annual distance travelled by some individuals being at least 5,000 kilometres, the longest of any terrestrial mammal (1) (2). Migration routes often involve crossing rivers and fjords, and, with its buoyant, air-filled coat, the reindeer is an excellent swimmer (1) (4).
During the day, the reindeer is almost constantly on the move. As it walks, the reindeer produces a characteristic clicking sound caused by a tendon in the foot slipping over the bone (2) (5) (6). At a run, the reindeer can reach speeds of 60 to 80 kilometres per hour (2).
A wide range of plants make up the diet of the reindeer (2), with this species typically selecting the food that is the most nutritious and easily digestible (3). New green growth and leaves are taken in spring and summer, while in the winter the reindeer uses its excellent sense of smell to find mats of lichen and plants hidden under the snow (2) (3). Remarkably, reindeer can see ultraviolet light which also helps them to find food during the winter (10). Like other ruminants, the reindeer has a compartmentalised stomach and relies on micro-organisms and re-chewing in order to digest its food (3).
The antlers of the reindeer are re-grown each year, and during the growing period they have a well-developed blood supply and are covered in fur, or ‘velvet’ (4). Once the antlers are fully grown, they harden into bone and the blood supply is stopped and the velvet brushed off (4). The breeding season, or rut, usually begins in autumn, and the male reindeer will compete to control a harem of 5 to 15 females (2). During this time the male uses the antlers in displays, threats and fights (5). Fighting between male reindeer can lead to serious injury or even death, and involves shoving and wrestling. A male reindeer may also take parts in bouts of ‘bush thrashing’, where they thrash their antlers through vegetation (5). The antlers of the adult male reindeer are shed after the breeding season, while a younger male reindeer may retain them into winter or even spring (3).
Mating occurs mainly in October, and the female gives birth the following May or June, after a gestation period of 227 to 229 days. A single calf is usually born, although twins are not unheard of, and the young reindeer can follow its mother after only one hour, and outrun a human after only a day (2). The young are weaned after around six months (1). The female reindeer retains the antlers until after giving birth, and this is thought to aid them in competing for food during the winter (3) (4).
The reindeer has a number of natural predators, including wolves, bears and cougars (1) (5). The maximum age for a wild reindeer is thought to be around 15 years, though an individual in captivity has been known to live to just over 20 years (2).
The reindeer has a circumpolar distribution which spans the northern parts of North America and Eurasia (1) (3) (4). Although historically more widespread, in North America the reindeer can now be found Alaska, Canada and the northernmost parts of the United States. In Europe, the reindeer occurs in Norway and Finland, and it can also be found in Russia, Greenland, Iceland and Mongolia (1) (3).
The northernmost population of reindeer occurs on the islands of Svalbard, in the High Arctic (9).
The reindeer inhabits Arctic and sub-Arctic tundra, as well as boreal coniferous forest. In parts of its range, it also inhabits mountainous areas (1) (2).
The reindeer is classified as Vulnerable (VU) on the IUCN Red List (1).
Although the reindeer may not be considered to be globally threatened, it is hunted extensively for its meat, fur and antlers, and has disappeared from areas of its former range, including Germany, Poland, and the southern limits of its range in the United States (1) (2). There were originally an estimated 5 million reindeer present in Russia, with this number reaching a low of 300,000 individuals in 1940. Wild reindeer have also been threatened by persecution from domestic reindeer herders, as well as habitat destruction and modification, which sometimes results in the blockage of migration routes (2).
Another threat to the reindeer of North America is a parasite carried by the white-tailed deer (Odocoileus virginianus), whose range is spreading northwards due to habitat modification (2). While the parasite has no effect on the white-tailed deer, it is fatal to the reindeer (1) (2). In Finland, the reindeer may also be at risk of hybridisation with semi-domesticated animals (1).
The reindeer may be affected by future climate change, which could increase the frequency of rain and subsequent icing over of this species food sources, leading to starvation. Warmer weather could disrupt migration routes by affecting the break up of sea ice, and could also increase the number of parasites of reindeer (1).
The reindeer is protected in Europe by its listing on Appendix III of the Convention on the Conservation of European Wildlife and Natural Habitats (also known as the Bern Convention), which aims to regulate the exploitation of this species (1) (11). It is also listed on Appendix II of the EU Habitats and Species Directive, which means that protective measures must be taken to ensure its conservation (1) (12).
Hunting of the reindeer is now strictly controlled in Norway and Russia, though poaching may still occur, and fencing has been erected in Finland to prevent the hybridisation of wild reindeer with semi-domesticated animals (1).
The Peary caribou (Rangifer tarandus pearyi) subspecies is considered to ‘endangered’ by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC) (13), and is protected under the federal Species at Risk Act (SARA), and by land-claim agreements that recognise and specify Aboriginal rights to harvest wildlife (14).
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- Boreal forest
- The sub-Arctic forest of the high northern latitudes that surrounds the North Pole and is mainly composed of coniferous trees.
- The state of being pregnant; the period from conception to birth.
- Cross-breeding between two different species or subspecies.
- A composite organism made up of a fungus in a co-operative partnership with an alga. Owing to this partnership, lichens can thrive in harsh environments such as mountaintops and polar regions. Characteristically forms a crustlike or branching growth on rocks or tree trunks.
- Referring to the visible or measurable characteristics of an organism.
- An organism that derives its food from, and lives in or on, another living organism at the host’s expense.
- A digestive process in which swallowed food is regurgitated, rechewed and then swallowed again.
- The mating season.
- A population usually restricted to a geographical area that differs from other populations of the same species, but not to the extent of being classified as a separate species.
- The science of classifying organisms, grouping together animals which share common features and are thought to have a common ancestor.
- Treeless, grassy plains characteristic of Arctic and sub-Arctic regions. They are very cold and have little rainfall.
IUCN Red List (July, 2017)
Nowak, R.M. (1999) Walker's Mammals of the World. Johns Hopkins University Press, Baltimore.
Hummel, M. and Ray, J.C. (2008) Caribou and the North: A Shared Future. Dundurn Press, Toronto.
Blix, A.S. (2005) Arctic Animals and their Adaptations to Life on the Edge. Tapir Academic Press, Trondheim.
Shackleton, D. (1999) Hoofed Mammals. UBC Press, Vancouver.
Ultimate Ungulate - Reindeer (March, 2012)
Macdonald, D. (2001) The New Encyclopedia of Mammals. Oxford University Press, Oxford.
Geist, V. (2006) Defining subspecies, invalid taxonomic tools, and the fate of the woodland caribou. Rangifer, 17: 25-28.
Colman, J.E., Jacobsen, B.W. and Reimers, E. (2001) Summer response distances of Svalbard reindeer Rangifer tarandus platyrhynchus to provocation by humans on foot. Wildlife Biology,7: 275-283.
Hogg, C. et al. (2011) Arctic reindeer extend their visual range into the ultraviolet. Journal of Experimental Biology, 214(12): 2014-2019.
Convention on the Conservation of European Wildlife and Natural Habitats (Bern Convention) (March, 2012)
EU Habitats Directive (March, 2012)
Committee on the Status of Endangered Wildlife in Canada (COSEWIC) (March, 2012)
Species at Risk Public Registry (SARA) (March, 2012)