Caribou

Caribou (North America)
Male Porcupine caribou R. t. granti in Alaska
Conservation status
Least Concern  (IUCN 3.1)[1]
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Mammalia
Order:	Artiodactyla
Family:	Cervidae
Subfamily:	Capreolinae
Genus:	Rangifer C.H. Smith, 1827
Species:	R. tarandus
Binomial name
Rangifer tarandus (Linnaeus, 1758)
Subspecies in North America
R. t. caribou – Canada and U.S R. t. granti – Alaska, Yukon R. t. groenlandicus – Nunavut, NWT, western Greenland R. t. pearyi – Baffin Island, Nunavut, NWT Also see text
Approximate range of caribou subspecies in North America. Overlap is possible for contiguous range. 1.Rangifer tarandus caribou subdivided into ecotypes: woodland (boreal), woodland (migratory), woodland (montane), 2.R t Dawsoni extinct 1907, 3. R t granti, 4.R t groenlandicus, 5.Groenlandicus/Pearyi 6. R t pearyi
Synonyms
reindeer in Europe and Eurasia

Caribou (North America) refers to any of several North American subspecies, ecotypes, populations, and herds^[2] of the species Rangifer tarandus.^[3] In North America caribou vary in size from the smallest, the Peary caribou, to the largest, the boreal woodland caribou. The North American range of caribou extends from Alaska, through the Yukon, the Northwest Territories, Nunavut, into the boreal forest and south through the Canadian Rockies and the Columbia and Selkirk Mountains.^[4] Barren-ground, Porcupine caribou and Peary caribou live in the tundra while the shy woodland caribou, prefers the boreal forest. Two major subspecies in North America, the R. t. granti and the R. t. groenlandicus form large herds and undertake lengthy seasonal migrations from birthing grounds, to summer and winter feeding grounds in the tundra and taiga. The migrations of R. t. granti Porcupine herds are among the longest of any terrestrial mammal.^[4] Barren-land caribou are also found in western Greenland, but the larger herds are in Alaska, the Northwest Territories, and Nunavut.^[5]

The circumpolar species itself, Rangifer tarandus, at a global level, is listed by the International Union for Conservation of Nature (ICUN) "as Least Concern due to a wide circumpolar distribution and presumed large populations."^[6] The populations of subspecies, ecotypes, populations and herds of caribou in North America are in decline^[7][8][9] and one subspecies, the iconic boreal woodland caribou, has been listed by COSEWIC as threatened since 2002.^[10]

The George River caribou herd (GRCH), in the Ungava region of Quebec and Labrador in eastern Canada was once the world's largest herd with 800,000–900,000 animals. By 2012 the herd numbered 27,600 and declined to 14,200 animals in 2014.^[11]

The meta-population of the more-sedentary subspecies R. t. caribou, or woodland caribou, spans the boreal forest from the Northwest Territories to Labrador. They are shy animals whose main food source is arboreal lichens^[9] of the mature forests^[12] and mainly live in marshes, bogs, lakes, and river regions.^[13][14] Since it takes hundreds of years for a biomass of tree lichen to be adequate to sustain boreal woodland caribou populations, deforestation has been a major factor in the decline of their numbers.^[9] The historic range of the boreal woodland caribou covered over half of present-day Canada,^[15] stretching from Alaska to Newfoundland and Labrador and as far south as New England, Idaho, and Washington. The smallest subspecies in North America, the Peary caribou is found in the High and Low Arctic, in the Northwest Territories (particularly, Banks Island) and in Nunavut (mainly Baffin Island).

The caribou is a specialist that is well adapted to cooler climates, with hollow-hair fur that covers almost all of its body including its nose, and provides insulation in winter and flotation for swimming.^[4] Caribou can reach a speed of 60–80 km/h (37–50 mph).^[1] Young caribou can already outrun an Olympic sprinter when only a day old.^[16] The caribou's favourite winter food is fruticose deer lichen. Seventy percent of the diet of woodland caribou consists of arboreal lichen which take hundreds of years to grow and are therefore only found in mature forests.^[12]

Although there are many variations in colour and size, Canadian Geographic magazine states that in general, barren-ground caribou have larger antlers than the woodland caribou subspecies. Barren-ground caribou have large distinguishing white patches of fur that extend beyond the neck onto the back, a white muzzle and a face that is darker than the rest of the body. Their fur is sandy-beige in winter and light brown in summer. The woodland caribou have a wider more compact body and wider antlers. The coat is a rich dark brown in summer and dark grey in winter. Both the barren-ground and woodland caribou often have white "socks" above their hooves.^[17] On average the male weighs 90–110 kg (200–240 lb) and measures 0.9–1.7 m (3.0–5.6 ft) in shoulder height. The woodland caribou are the largest, and the Peary caribou are the smallest. The largest Alaskan male Porcupine caribou can weigh as much as 310 kilograms (680 lb).

Female caribou can live up to 17 years, and male caribou live about 13 years.^[18]

Both sexes grow antlers, though in some woodland caribou populations, the females lack antlers completely. Antlers are larger in males.

Caribou are an integral part of First Nations and Inuit oral histories and legends including the Gwich'in creation story of how Gwich’in people and the caribou separated from a single entity.^[19]

Nomenclature

The term "caribou" derives from the Mi'kmaw word "qalipu" (pronounced /kah-li-bu/), literally meaning "the shoveller". Caribou have been referred to as reindeer or wild reindeer depending on context, specifically in Alaska^[3] where attempts were made at importing domesticated reindeer from Siberia. There are occurrences of the subspecies barren-ground caribou in western Greenland. Current classifications of Rangifer tarandus, either with prevailing taxonomy on subspecies, designations based on ecotypes, and natural population groupings, fail to capture "the variability of caribou across their range in Canada" needed for effective species conservation and management.^[20] "Across the range of a species, individuals may display considerable morphological, genetic, and behavioural variability reflective of both plasticity and adaptation to local environments."^[21] COSEWIC developed Designated Unit (DU) attribution to add to classifications already in use.^[20]

Naming and etymology

The name caribou comes, through the French, from the Mi'kmaq xalibu or Qalipu meaning "the one who paws".^[22] Marc Lescarbot in his publication in French,^[23] used the term "caribou." Silas Tertius Rand translated the Mi'kmaq word Kaleboo as "caribou" in his Mi'kmaq-English.^[24][25] The Gwich’in people have over two dozen distinct caribou-related words.^[19] In Inuktitut, spoken in the eastern Arctic, the caribou is known by the name "tuktu".^[26]

With its range across North America and depth of history, Rangifer tarandus has countless aboriginal names. The nomadic Naskapi people followed George River Caribou Herd.^[27] "By the late 1940s, the pressures of the fur trade, high rates of mortality and debilitation from diseases communicated by Europeans, and the effects of the virtual disappearance of the herd, reduced the Naskapi to a state where their very survival was threatened."^[27][28]

Names for caribou in indigenous languages

caribou	syllabics or	meaning	language	people	region	R. t. subspecies and ecotype	language family
qalipu		one who paws	Mi'kmaq	Mi'kmaq	what is now Eastern Canada and U.S.	R. t. caribou	Algonquian
atíhko		caribou	Woods Cree	Cree	Northern Manitoba	R t groenlandicus	Algonquian
atihkw				Cree-Montagnais-Naskapi	region	R. t. caribou	Algonquian
bedzeyh[29]			Koyukon language	Koyukon	Alaska (Western Arctic caribou herd)	R. t. granti	Athabaskan
vadzaih[19]		caribou	Gwich’in language	Gwich’in	Northwest Territories (Porcupine River)	R. t. granti, Blue Nose herd, R.t. caribou	Athabaskan
wëdzey[30]			Hän language	Hän			Athabaskan
tuktu[31]			Inuktitut	Inuit	Nunavut (barren-ground) and Labrador	R. t. groenlandicus	Eskimo–Aleut
tuttu[32]			Inupiaq language	Inupiat people	Alaska	R. t. granti (Western Arctic caribou herd)	Eskimo–Aleut
tuntu[29]			Yup'ik	Yup'ik	Alaska (Western Arctic caribou herd)	R. t. granti	Eskimo–Aleut

Biology and behaviour

Reproduction and life-cycle

According to SARA, in their latest compilation on woodland caribou,^[33]

"The rut, or mating period, for caribou usually occurs in late September and the first half of October. Caribou cows begin breeding as early as 16 months of age; most breed annually by the time they are 28 months old, typically giving birth to a single calf the following spring (mid-May to mid-June). The males may theoretically breed at 18 to 20 months of age, but most probably have no opportunity before their third or fourth year. During the rut, males engage in frequent and furious sparring battles with their antlers. Large males with large antlers do most of the mating. To calve, females travel to isolated, relatively predator-free areas such as islands in lakes, peatlands, lakeshores, or tundra. Group size is lowest during calving and in summer; it increases before the rut and may decline or increase over the winter. Group size at all seasons is larger for forest-tundra caribou than forest-dwelling caribou. Survival rates for calves average between 30% and 50%, but can vary from almost none to 100%. Many factors interact to determine calf survival, including quality and quantity of forage (for pregnant females and in the first year of life), number of predators, and weather. The potential for very high survival means that it is possible for local populations to increase rapidly when conditions are favourable.

— SARA 2014

Caribou mate in October and the gestation period is about 228–234 days.^[18] In May or June the calves are born.^[18] Males live 4 years less than the females whose maximum longevity is about 17 years. Females with a normal body size who have had sufficient summer nutrition, can begin breeding anytime between the ages of one to three years.^[18] When a female has undergone nutritional stress, it is possible for her to not reproduce for the year.^[34] Dominant males, those with larger body size and antler racks, inseminate more than one doe a season.

To calve, "females travel to isolated, relatively predator-free areas such as islands in lakes, peatlands, lakeshores, or tundra."^[33] As females select the habitat for the birth of their calves, they are more wary than males.^[18] Dugmore noted that in their seasonal migrations the herd follows a doe for that reason.^[35] Newborns weigh on average 6 kg (13 lb).^[36]

As the weather cools in the fall, barren-ground and Porcupine caribou would leave their summer grounds forming large herds and migrate south for the winter. They would start mating when large lakes were frozen over. Just prior to mating, the males of both caribou were in prime condition, fat and ready to battle for mates. Bulls at this time were more aggressive and they were usually alone.^[37]

cabu

Antlers

Male caribou used their antlers to compete with other males during the mating season. "During the rut, males engage in frequent and furious sparring battles with their antlers. Large males with large antlers do most of the mating."^[33] The velvet that covers growing antlers is a highly vascularized skin. When the antler growth is fully grown and hardened, the velvet is shed or rubbed off. Caribou continue to migrate until the bull caribou had spent the back fat (IOHP 065). After the mating season, the male caribou shed his antlers, growing a new pair the next summer with a larger rack than the previous year. As the antler grows it is covered in thick velvet, filled with blood vessels and spongy in texture. In the woodland caribou, the velvet is brown.^[37]

...these antlers get detached every year… Young males lose the velvet from the antlers much more quickly than female caribou even though they are not fully mature. They start to work with their antlers just as soon as the velvet starts to fall off. The young males engage in fights with their antlers towards autumn… soon after the velvet had fallen off they will be red, as they start to get bleached their colour changes… When the velvet starts to fall off the antler is red because the antler is made from blood. The antler is the blood that has hardened, in fact the core of the antler is still bloody when the velvet starts to fall off, at least close to the base.

— Noah Piugaattuk of Igloolik (IOHP 037)

In most caribou subspecies, both males and females sexes grow antlers—unique among cervid species. Some R. t. caribou ecotype females do not have antlers. The antlers typically have two separate groups of points, a lower and upper. There is considerable subspecific variation in the size of the antlers (e.g., rather small and spindly in R. t. pearyi),^[38] but, on average, the bull's antlers are the second largest of any living deer, after the moose. In the largest caribou—R. t. caribou—antlers of large males can range up to 100 cm (39 in) in width^[39] and 135 cm (53 in) in beam length. They have the largest antlers relative to body size among living deer species.

Males have larger, more-extravagant antlers, but most females have antlers too during part of the year, although some females may have only one antler or no antlers at all.^[40][13] (Boreal Caribou ATK Reports, 2010-2011) The antler's main beam begins at the brow "extending posterior over the shoulders and bowing so that the tips point forwards. The prominent, palmate brow tines extend forward, over the face."^[41]

In late fall or early winter after the rut, male caribou lose their antlers. Female caribou keep their antlers until they calve. Antlers begin to grow on male caribou in March and on female caribou in May or June. This process is called antlerogenesis. While the antler is developing, it is covered in velvet which is rubbed off when the antler bone hardens. This velvet is dark brown on woodland or barren-ground caribou and slate grey on Peary caribou.^[41] Antlers grow very quickly every year on the males. Velvet lumps in March can develop into a rack measuring more than a metre in length (3 ft) by August.

When bull caribou shed their antlers in early to midwinter, the antlered female caribou acquire the highest ranks in the feeding hierarchy, gaining access to the best forage areas. These cows are healthier than those without antlers.^[42] Calves whose mothers do not have antlers are more prone to disease and have significantly higher mortality.^[42] Females in good nutritional condition, for example, during a mild winter with good winter range quality, may grow new antlers earlier as antler growth requires high intake.^[42] Antler size measured in number of points reflects the nutritional status of the caribou and climate variation of its environment.^[43][44] The number of points on male caribou increased from birth to five-years of age and remained relatively constant from then on.^[45] "In male caribou, antler mass (but not the number of tines) varies in concert with body mass."^{[46] [47]}

While antlers of bull woodland caribou are typically smaller than barren-ground caribou, they can be over one metre across. They are flattened, compact, and relatively dense.^[48] Geist describes them as frontally emphasized, flat-beamed antlers.^[49] Woodland caribou antlers are thicker and broader than those of the barren-ground caribou, and their legs and heads are longer.^[48] The antler velvet of the barren-ground caribou and woodland caribou are dark chocolate brown.^[50]

Quebec-Labrador bull caribou antlers can be significantly larger and wider than other woodland caribou. Central barren-ground bull caribou are perhaps the most diverse in configuration and can grow to be very high and wide. Mountain caribou are typically the most massive with the largest circumference measurements.

Peary caribou and the Dolphin-Union Caribou herd have light slate-grey antler velvet.^[51]

Size

In all caribou subspecies males are 10% to 50% heavier than females. Weight varies drastically seasonally with males losing as much as 40% of their pre-rut weight.^[36]

The woodland caribou is the largest of the North American caribou subspecies.^[52] Their legs and heads are longer than the barren-ground caribou.^[48] Porcupine, the barren-ground Bluenose caribou herd, and woodland caribou all occupy Gwich'in land. According to traditional knowledge woodland caribou are easily distinguishable from Porcupine caribou. They are much bigger than the Porcupine caribou "half between a caribou and a moose."^[53] Peary caribou are the size of a deer.

Size male caribou

caribou	total length[36]	height at shoulder	weight
average male caribou all subspecies	167–298 cm (5.48–9.78 ft)[36]	87–158 cm (2.85–5.18 ft)[36]	66–300 kg (146–661 lb)[36]
largest male			310 kg (680 lb)

Size female caribou

caribou	total length	height at shoulder	weight
average female caribou all subspecies	105.4–234 cm (41.5–92.1 in)[36]	80–139 cm (31–55 in)[36]	51–156 kg (112–344 lb)[36]

Caribou across North America range in size. In the farthest west, Alaskan caribou females usually measure 162–205 cm (5.31–6.73 ft) in length and weigh 80–120 kg (180–260 lb).^[54] The males (or "bulls") are typically larger (although the extent to which varies in the different subspecies), measuring 180–214 cm (71–84 in) in length and usually weighing 159–182 kg (351–401 lb),^[54] though exceptionally large males have weighed as much as 318 kg (701 lb).^[54] Shoulder height typically measure from 85 to 150 cm (2.79 to 4.92 ft), and the tail is 14 to 20 cm (0.46 to 0.66 ft) long.

Pelage

The colour of the fur varies considerably, both individually and depending on season and subspecies. The Peary caribou are whiter and relatively small; woodland caribou are darker brown with unique patches of white fur. The Alaskan and barren-ground caribou are greyer than the woodland caribou.^[38] The coat has two layers of fur: a dense woolly undercoat and longer-haired overcoat consisting of hollow, air-filled hairs.^{[55][Notes 1][55]} Fur is the primary insulation factor that allows caribou to regulate their core body temperature in relation to their environment, the thermogradient, even if the temperature rises to 100 °F (38 °C).^[56] In 1913 Dugmore noted how the woodland caribou swim so high out of the water, unlike any other mammal, because their hollow, "air-filled, quill-like hair" acts as a supporting "life jacket."^[35]

The boreal woodland caribou is well-adapted to cold environments with a compact body covered with a thick and long coat (thicker in winter than in summer).^[13] They with a large blunt muzzle, short wide ears, and a small tail. Adults have a brown to dark-brown coat in summer,^[13] becoming grayer in winter.^[13] Its body is covered in long, thick hairs that almost uniformly dark brown^[49] in summer and nearly gray in winter. Adults have distinctive creamy white neck, mane, shoulder stripe, underbelly, underside of the tail, and patch above each hoof^[57] (Boreal Caribou ATK Reports, 2010-2011).^[58] The woodland caribou is darker in colour than the barren-ground caribou.^[53]

Hooves

The caribou has large feet with crescent-shaped, cloven hooves for walking in snow or swamps. According to the Species at Risk Public Registry (SARA), woodland,^[33]

"Caribou have large feet with four toes. In addition to two small ones, called "dew claws," they have two large, crescent-shaped toes that support most of their weight and serve as shovels when digging for food under snow. These large concave hooves offer stable support on wet, soggy ground and on crusty snow. The pads of the hoof change from a thick, fleshy shape in the summer to become hard and thin in the winter months, reducing the animal’s exposure to the cold ground. Additional winter protection comes from the long hair between the "toes"; it covers the pads so the caribou walks only on the horny rim of the hooves."

— SARA 2014

Their hooves adapt to the season: in the summer, when the tundra is soft and wet, the footpads become sponge-like and provide extra traction. In the winter, the pads shrink and tighten, exposing the rim of the hoof, which cuts into the ice and crusted snow to keep it from slipping. This also enables them to dig down (an activity known as "cratering").^[59] "In the winter, the fleshy pads on these toes grow longer and form a tough, hornlike rim. Caribou use these large, sharp-edged hooves to dig through the snow and uncover the lichens that sustain them in winter months. Biologists call this activity "cratering" because of the crater-like cavity the caribou’s hooves leave in the snow."^[60] through the snow to their favorite food, a lichen known as reindeer moss.

Countercurrent heat exchange

Blood moving into the legs is cooled by blood returning to the body in a countercurrent heat exchange (CCHE), a highly efficient means of minimizing heat loss through the skin's surface. In the CCHE mechanism, in cold weather, blood vessels are closely knotted and intertwined with arteries to the skin and appendages that carry warm blood with veins returning to the body that carry cold blood causing the warm arterial blood to exchange heat with the cold venous blood. In this way, their legs for example are kept cool, maintaining the core body temperature nearly 30 °C (54 °F) higher with less heat lost to the environment. Heat is recycled instead of being dissipated. The "heart does not have to pump blood as rapidly in order to maintain a constant body core temperature and thus, metabolic rate." CCHE is present in animals like caribou, fox and moose living in extreme conditions of cold or hot weather as a mechanism for retaining the heat in (or out of) the body. These are countercurrent exchange systems with the same fluid, usually blood, in a circuit, used for both directions of flow.^[61]

North American caribou, have specialized counter-current vascular heat exchange in their nasal passages.^[62] Temperature gradient along the nasal mucosa is under physiological control.^[62] Incoming cold air is warmed by body heat before entering the lungs, and water is condensed from the expired air and captured before the deer's breath is exhaled, used to moisten dry incoming air and possibly absorbed into the blood through the mucous membranes.^[62] Like moose, caribou have specialized noses featuring nasal turbinate bones that dramatically increase the surface area within the nostrils.

Clicking sound

According to thirty-year veteran, David Shackleton, University of British Columbia emeritus professor, who has published widely on ungulates and other large mammals, the clicking sound made by caribou as they walk is caused by small tendons slipping over bone protuberances (sesamoid bones) in their feet.^[63][59] Dugmore, who in 1913 spent considerable time in the field studying Newfoundland woodland caribou at close range, considered this curious clicking sound, made when a caribou was walking or running, which he thought was made by some internal mechanism of the foot, to be one of the caribou's strangest characteristics. The sound occurred when the full weight of the foot is on the ground or just after it is relieved of the weight. On a quiet day, the sound can be heard 150 feet (46 m) or more away.^[35]

Diet

Caribou licking salt from roadway in British Columbia

Rangifer tarandus are ruminants, having a four-chambered stomach. They mainly eat lichens in winter, especially reindeer moss—the "only large mammal able to metabolize lichen owing to specialized bacteria and protozoa in their gut."^[64] Each ecotype eats a diet based on the surrounding ecology. Mountain caribou eat lichen from trees, for example. They have been known to eat their own fallen antlers, probably for calcium. They also eat the leaves of willows and birches, as well as sedges and grasses.

Seasonal body composition

Caribou have developed adaptions for optimal metabolic efficiency during warm months as well as for during cold months.^[65] The body composition of caribou varies highly with the seasons. Of particular interest is the body composition and diet of breeding and non-breeding females between seasons. Breeding females have more body mass than non-breeding females between the months of March and September with a difference of around 10 kg more than non-breeding females. From November to December, non-breeding females have more body mass than breeding females as non-breeding females were able to focus their energies towards storage during colder months rather than lactation and reproduction. Body masses of both breeding and non-breeding females peaked in September. During the months of March through April, breeding females have more fat mass than the nonbreeding females with a difference of almost 3 kg. After this however, nonbreeding females on average have a higher fat mass than the breeding females.^[66]

The environmental variations play a large part in caribou nutrition, as winter nutrition is crucial to adult and neonatal survival rates.^[67] Lichens are a staple during the winter months as they’re a readily available food source, which reduces the reliance on stored body reserves.^[68] Lichens are a crucial part of the caribou diet, however they are less prevalent in the diet of pregnant caribou compared to non-pregnant individuals. The amount of lichen in a diet is found more in non-pregnant adult diets than pregnant individuals due to the lack of nutritional value. Although lichens are high in carbohydrates, they are lacking in essential proteins that vascular plants provide. The amount of lichen in a diet decreases in latitude that results in nutritional stress being higher in areas with low lichen abundance.^[69]

Migration and range

Alaskan caribou aggregation in 1002 Area, Arctic National Wildlife Refuge (April 2008)

Some populations of the North American caribou, for example, many herds in the subspecies, the barren-ground caribou, and some woodland caribou in Ungava and Labrador, migrate the farthest of any terrestrial mammal, travelling up to 5,000 km (3,100 mi) a year, and covering 1,000,000 km² (390,000 sq mi).^[1][70] Other North American populations, the woodland caribou (boreal) for example, are largely sedentary.^[71] Smaller herds and island herds like R. t. pearsoni make the shortest migrations least.

Normally travelling about 19–55 km (12–34 mi) a day while migrating, the caribou can run at speeds of 60–80 km/h (37–50 mph).^[1] Young caribou can already outrun an Olympic sprinter when only a day old.^[72] During the spring migration smaller herds will group together to form larger herds of 50,000 to 500,000 animals. During autumn migrations groups become smaller and they begin to mate. During the winter, migratory herds travel to winter feeding grounds along coastlines in the tundra above the tree line. Below the tree line they shift to the forest for winter feeding. By spring, groups leave their winter grounds to go to the calving grounds. A caribou can swim easily and quickly, normally at 6.5 km/h (4.0 mph) but if necessary at 10 km/h (6.2 mph), and migrating herds will not hesitate to swim across a large lake or broad river.^[1]

Ecology

Distribution and habitat

Originally, the caribou range spanned the northern conterminous USA from Washington to Maine. In the 19th century, it was apparently still present in southern Idaho.^[1] During the late Pleistocene era, reindeer were found as far south as Nevada and Tennessee in North America.^[73]

According to the Grubb,^[5] Rangifer tarandus is "circumboreal in the tundra and taiga" from "Alaska (USA) and Canada including most Arctic islands, and USA (Northern Idaho and the Great Lakes region).^[5]

Predators

Predation by wolves, bears, coyotes, cougar, and lynx and over-hunting by people in some areas, contribute to the decline of the populations of woodland caribou.^[33] Healthy caribou are faster than their predators including wolves. Wolverines—who are themselves a threatened species in some parts of Canada— can kill adult caribou. Bears prey on caribou but are most likely to attack weaker animals, such as calves and sick deer. As carrion, caribou are fed on opportunistically by foxes, ravens, hawks, and golden eagles (Aquila chrysaetos).

White-tailed deer, a threat to caribou

White-tailed deer (Odocoileus virginianus) commonly carry meningeal worm or brainworm, a nematode parasite that causes caribou, moose (Alces alces), elk (Cervus canadensis), and mule deer (Odocoileus hemionus) to develop fatal neurological symptoms^[74][75][76] which include a loss of fear of humans. White-tailed deer that carry this worm are partly immune to it.^[77] Changes in climate and habitat beginning in the twentieth century have expanded range overlap between white-tailed deer and caribou, increasing the frequency of infection within the caribou population. This increase in infection is a concern for wildlife managers.

Human activities, such as "clear-cutting forestry practices, forest fires, and the clearing for agriculture, roadways, railways, and power lines,"^[78] favour the conversion of habitats into the preferred habitat of the white-tailed deer-"open forest interspersed with meadows, clearings, grasslands, and riparian flatlands."^[78]

Wolves

Through human activities in northeastern Alberta for example, there have been dramatic changes in forest composition. The increase in young deciduous forest stands attract and sustain increased number of moose, elk and/or deer. These changes lead to increases in the number of predators, especially wolves, and a subsequent increase in predation threat to caribou.^[79][80] White-tailed deer (Odocoileus virginianus) expanded further north and west to Prince George as the land adjacent to the northern Rockies was converted by industry or agriculture into a habitat that is favourable to deer, widespread deciduous vegetation. As the density of white-tailed deer increased in the post-industrial period (2005–2009), so did the population of wolves (Canis lupus), the primary and natural predator of caribou. The higher density of wolves led to higher woodland caribou mortality. During this period wolves consumed more deer and fewer moose. Caribou increased 10-fold in the diet of wolves in northeast Alberta and caribou population trends in the region changed from stable to declining."^[81]

Wolves (canis lupus) are the natural and primary predators of caribou.^[82] Since the 1920s there have been no wolves on the island of Newfoundland. Without wolves, caribou can overgraze and out feed their range.^[83] In 1980, Slate Island, located in northern Lake Superior, 10 km (6.2 mi) south of the town of Terrace Bay, where there are no wolves or other predators, had the highest density of woodland caribou in the world with a population peaking at 660.^[84]

The population of woodland caribou in the northeastern corner of British Columbia is in an area with a high density of wolves and there is concern that the caribou herd is not self-sustaining.^[14] The woodland caribou population of the Selkirk Mountains in extreme northern Idaho, eastern Washington, and British Columbia is in an area with a high incidence of whitetail deer and wolves and caribou numbers declined dramatically.^[85][86][87]

In the preparation of their recovery strategy for woodland caribou in Alberta, the Alberta Woodland Caribou Recovery Team, concluded that wolf predation was the most common cause of adult woodland caribou mortality."^[80][88][89]

"Although caribou have co-existed with predators for millennia in Alberta, recent human activities and forest fires (both human and naturally caused) have increased the vulnerability of caribou to predation. Changes in forest composition and the development of access routes are thought to be primary causes. For example, both timber harvesting and fire increase the amount of young forest stands and of various plant species, which in many cases attract and sustain increased number of moose, elk and/or deer. These changes lead to increases in the number of predators, especially wolves, and a subsequent increase in predation threat to caribou.^[79][80] In addition, habitat loss and alteration (including carriers to caribou movement and reduced use of areas by caribou) may concentrate caribou in restricted portions of their range.^[90][91] Since maintaining low population densities is one of the ways that caribou avoid predation, this concentration of animals may lead to greater caribou mortality. Finally, research has demonstrated that linear access corridors facilitate wolf travel and hunting behaviour within caribou range.^[92][93] Continued industrial and/or non-industrial use of corridors may further facilitate wolf-hunting efficiency by compacting snow during winter."^[80]

The population of caribou in Pukaskwa National Park has "declined from approximately 30 caribou in the 1970s to an estimated four currently, largely due to predation by wolves and possibly black bears."^[94]

According to the Canadian Wildlife Federation in Canada, "Despite its vast range, the boreal population of woodland caribou [boreal ecotype of forest-dwelling woodland caribou] has been listed as threatened by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC) since 2002 and endangered in British Columbia. One of the main reasons numbers are dropping is that fewer calves are surviving their first year of life. The main cause is predation. More calves are being preyed on by wolves and black bears than ever before."^[52]

Insects harassment

Tormenting insects keep caribou on the move searching for windy areas like hilltops and mountain ridges, rock reefs, lakeshore and forest openings, or snow patches that offer respite from the buzzing horde. Gathering in large herds is another strategy caribou use to block insects.^[95]

"Changes in insect phenology – earlier emergence and increased abundance – indirectly reduce summer forage availability by reducing the amount of time Rangifer can spend foraging undisturbed.

— Vors 2013:16

Mosquitoes (Culicidae), black flies (Simuliidae), and oestrid flies (warble flies) Hypoderma tarandi and nose bot flies (Cephenemyia trompe) harass caribou herds particularly during the prime foraging period which is the post-calving and summer period. As temperatures on the tundra rose, the number of black and oestrid flies in the Bathurst barren-ground caribou herd study area in Northwest Territories increased.^[96] Feeding is inhibited and energy expended as panicked caribou attempt to escape insects resulting in loss of weight, poorer body condition and reproductive capacity.^[97] An adult reindeer will lose perhaps about 1 litre (0.26 US gal) of blood to biting insects for every week it spends in the tundra.^[16] So a warmer Arctic climate will produce better vegetation for foraging caribou, this will be offset by increased insect harassment by insects.^[96]

Taxonomy and evolution

The species taxonomic name Rangifer tarandus (reindeer, caribou) was defined by Carl Linnaeus in 1758. The subspecies taxonomic name, Rangifer tarandus caribou was defined by Gmelin in 1788.

According to the then-Canadian Wildlife Service Chief Mammalogist, Frank Banfield, in his often-cited A Revision of the Reindeer and Caribou, Genus Rangifer (1961),^[98] R. t. caboti (Labrador caribou), R. t. osborni (Osborn's caribou—from British Columbia) and R. t. terraenovae (Newfoundland caribou) were considered invalid and included in R. t. caribou.

Some recent authorities have considered them all valid, even suggesting that they are quite distinct. In their book entitled Mammal Species of the World, American zoologist Don E. Wilson and DeeAnn Reeder agree with Valerius Geist, specialist on large North American mammals, that this range actually includes several subspecies.^{[99][100][101][102][Notes 2]}

The woodland caribou's frontally emphasized, flat-beamed antlers are evident in this drawing by Foresman

Geist (2007) argued that the "true woodland caribou, the uniformly dark, small-manned type with the frontally emphasized, flat-beamed antlers", which is "scattered thinly along the southern rim of North American caribou distribution" has been incorrectly classified. He affirms that "true woodland caribou is very rare, in very great difficulties and requires the most urgent of attention."^[49]

In 2005, an analysis of mtDNA found differences between the caribou from Newfoundland, Labrador, south-western Canada and south-eastern Canada, but maintained all in R. t caribou.^[2]

Mallory and Hillis^[103] argued that, "Although the taxonomic designations reflect evolutionary events, they do not appear to reflect current ecological conditions. In numerous instances, populations of the same subspecies have evolved different demographic and behavioural adaptations, while populations from separate subspecies have evolved similar demographic and behavioural patterns... "[U]nderstanding ecotype in relation to existing ecological constraints and releases may be more important than the taxonomic relationships between populations."^[103]

Evolution

The caribou "evolved in North America and spread to Eurasia where they are known as reindeer."^[18] The "glacial-interglacial cycles of the upper Pleistocene had a major influence on the evolution" of Rangifer tarandus and other Arctic and sub-Arctic species. Much of the Late Pleistocene age was dominated by glaciation (the Wisconsin glaciation in North America and corresponding glacial periods in Eurasia). Rangifer tarandus was isolated in refugia during the last glacial - the Wisconsin in North America—extending approximately from 85,000 BP to 11,000 BP—and the Weishselian.^[104] According to research based on mitochondrial DNA, "ancestral populations of R. t. caribou likely survived the Wisconsin glaciation in separate refugia located south of the continental ice sheet, while other Rangifer tarandus subspecies"—R. t. groenlandicus and R. t. granti—"survived north of the ice sheet."^[2](Røed et al. 1991)^[104] Newfoundland caribou are most closely related to other woodland caribou (R. t. caribou) from Labrador, Quebec, and Alberta rather than barren-ground caribou (R.t groenlandicus and R. t. granti) from northern Canada and Alaska.^[2]

Phylogenetics

Phylogenetic analyses of caribou reveal that caribou were isolated by the ice sheet into two glacial refugia, a northern Beringia European Lineage (BEL) and North American Lineage (NAL)^[2][104] diverging about 300,000 years ago^[105][106] When the ice sheet melted, the NAL caribou "spread west across the boreal region, and north into the Rocky Mountains." The BEL caribou "spread south from the Beringean refugium in present-day western Yukon, north into the Arctic islands and eastward."^[107]

Subspecies

The canonical Mammal Species of the World (2005) recognized fourteen subspecies of Rangifer tarandus globally.^[5] Two of these subspecies are only in North America—Grant’s caribou and Peary caribou. Barren-land caribou are found in western Greenland, but the larger herds are in Alaska, the Northwest Territories and Nunavut.^[5]

subspecies of Rangifer tarandus in North America

subspecies	name	migratory	division![5] range	weight of male	evolution
R. t. caribou (Gmelin, 1788)[98]	Woodland caribou (Gmelin, 1788) – woodland caribou	sedentary[Notes 3]	boreal forest	Canada and U.S
R. t. granti[98]	Porcupine caribou Grant’s caribou	migratory	tundra	Alaska, Yukon	300 kg (660 lb)
R. t. groenlandicus (Borowski, 1780)[98]	barren-ground caribou(Borowski, 1780)	migratory	tundra	Nunavut, NWT, western Greenland	150 kg (330 lb)
R. t. pearyi (J. A. Allen, 1902)[98]	Peary caribou (J. A. Allen, 1902)	island species make local movements		Banks Island, NWT, High Arctic population (Baffin Island), Nunavut	smallest

Extinct subspecies of Rangifer tarandus in North America

subspecies	name	migratory	tundra	range	height of male	extinct since
R. t. dawsoni (Thompson-Seton, 1900)[98]	†Queen Charlotte Islands caribou	extinct	no	Queen Charlotte Islands	no data	1910

Subspecies of Rangifer tarandus in North America that are not part of Banfield's 1961 review[98]	subspecies	name	migratory	tundra	range	height of male
R. tarandus osborni** (J. A. Allen, 1902)[108][101]	Osborn's caribou J. A. Allen, 1902			British Columbia)	no data
R. t. terraenovae**(Bangs, 1896)[5][108][101]
R. t. caboti**(G. M. Allen, 1914)[5][108][101]

The table above includes R. tarandus caboti (Labrador caribou), R. tarandus osborni (Osborn's caribou – from British Columbia) and R. tarandus terraenovae (Newfoundland caribou). Based on Banfield's review in 1961,^[98] R. tarandus caboti (Labrador caribou), R. tarandus osborni (Osborn's caribou – from British Columbia) and R. tarandus terraenovae (Newfoundland caribou) were considered invalid and included in R. tarandus caribou. However, more recent authorities^{[Notes 4]} have considered them all valid, even suggesting that they are quite distinct.^[108][101] An analysis of mtDNA in 2005 found differences between the caribou from Newfoundland, Labrador, south-western Canada and south-eastern Canada, but maintained all in R. t. caribou.^[2]

Some of the species Rangifer tarandus and subspecies may be further divided by ecotype depending on several behavioural factors - predominant habitat use (northern, tundra, mountain, forest, boreal forest, forest-dwelling, woodland, woodland (mountain), woodland (boreal), woodland (migratory), spacing (dispersed or aggregated) and migration (sedentary or migratory).^{[82][109][110]}

Rangifer tarandus by country

North America

Approximate range of caribou subspecies in North America. Overlap is possible for contiguous range. 1.Rangifer tarandus caribou subdivided into ecotypes: woodland (boreal), woodland (migratory), woodland (montane), 2.R t Dawsoni extinct 1907, 3. R t granti, 4.R t groenlandicus, 5. Groenlandicus/Pearyi 6. R t pearyi

There are four living subspecies of R. tarandus, locally known in North America as caribou—R t. granti (Porcupine caribou), Rangifer tarandus caribou subdivided into ecotypes: woodland (boreal), woodland (migratory), woodland (montane), R t granti, R t groenlandicus and R t pearyi.

In North America, because of its vast range in a wide diversity of ecosystems, the subspecies Rangifer tarandus caribou is further distinguished by a number of ecotypes, including boreal woodland caribou, mountain woodland caribou and migratory woodland caribou).^{[82][109][110]} Populations—caribou that do not migrate—or herds—those that do migrate—may not fit into narrow ecotypes. For example, Banfield's 1961 classification of the migratory George River Caribou Herd, in the Ungava region of Quebec, as subspecies Rangifer tarandus caribou, woodland caribou, remains—although other woodland caribou are mainly sedentary.

United States

Although there are remnant populations of R. t. caribou boreal woodland caribou in the northern United States, most of U.S. caribou populations are in Alaska. There are four herds in Alaska, the Western Arctic herd, Teshekpuk Lake herd, the Central Arctic herd and the Porcupine herd.

Alaska

Alaska has several herds of R t granti. The largest is the Western Arctic Caribou Herd but the smaller Porcupine caribou herd has the longest migration of any terrestrial mammal on earth with a vast historical range. The smaller Central Arctic herd (32 000 in 2002).

Porcupine caribou herd

Male Porcupine caribou R. t. granti in Alaska

Migratory caribou herds are named after their birthing grounds, in this case the Porcupine River, which runs through a large part of the range of the Porcupine herd. Individual herds of migratory caribou once had over a million animals per herd, and could taking over ten days to cross the Yukon River, but these numbers dramatically declined with habitat disturbance and degradation. Though numbers fluctuate, the herd comprises approximately 169 000 animals (based on a July 2010 photocensus).^[54] The R. t. grantis Porcupine herd's annual migrations of 1,500 miles (2,400 km) are among the longest of any terrestrial mammal.^[4] Their range spans approximately 260,000 km² (64,000,000 acres), from Dawson City, Yukon to Aklavik, NWT to Kaktovik, Alaska on the Beaufort Sea. The Porcupine caribou or Grant's caribou(Rangifer tarandus granti) is a subspecies with a vast range that includes northeastern Alaska and the Yukon, and is therefore cooperatively managed by government agencies and aboriginal peoples from both countries.^[108][2] The Gwich'in people, followed the Porcupine caribou herd—their primary source of food, tools, and clothing—for thousands of years—according to oral tradition, for as long as 20,000 years. They continued their nomadic lifestyle until the 1870s.^[111] This herd is also traditional food for the Inupiat, Inuvialuit, Hän, and Northern Tutchone. There is currently controversy over whether possible future oil drilling on the coastal plains of the Arctic National Wildlife Refuge, encompassing much of the Porcupine caribou calving grounds, will have a severe negative impact on the caribou population or whether the caribou population will grow.

Unlike many other Rangifer tarandus subspecies and their ecotypes, the Porcupine herd is stable at relatively high numbers, but the 2013 photo-census was not counted by January 2014.^[112] The peak population in 1989 of 178,000 animals was followed by a decline by 2001 to 123,000. However, by 2010, there was a recovery and an increase to 169,000 animals.^[112][54]

Many Gwich'in people, who depend on the Porcupine caribou, still follow traditional caribou management practices that include a 1981 prohibition against selling caribou meat and limits on the number of caribou to be taken per hunting trip.^[113]

All three herds cross the Brooks Range in their annual migrations. The Western Arctic herd reached a low of 75,000 in the mid-1970s. In 1997 the 90,000 WACH changed their migration and wintered on Seward Peninsula where Alaskan reindeer normally wintered. The reindeer, part of the Reindeer Project herds brought north from Siberia via Alaska, joined the WACH on their summer migration and disappeared.^[114] The WACH reached a peak of 490,000 in 2003 and then declined to 325,000 in 2011.^[54][29] In 2008, the Teshekpuk Lake herd had 64,107 animals and the Central Arctic herd had 67,000.^[115][116]

Reindeer imported to Alaska

Reindeer were imported from Siberia in the late 19th century and from Norway in the early 1900s as semi-domesticated livestock in Alaska.^[117][118] Reindeer interbreed with native caribou subspecies.

Canada

Nunavut

The barren-ground caribou subspecies R. t. groenlandicus,^[98] a long-distance migrant, includes large herds in the Northwest Territories and in Nunavut, for example the Beverly, the Ahiak and Qamanirjuaq herds. In 1996 the population of the Ahiak herd was approximately 250 000 animals.

Ahiak, Beverly, Qamanirjuaq herds

The Ahiak, Beverly, and Qamanirjuaq herds are barren-ground caribou.

The Beverly herd of barren-ground caribou, Thelon River, Nunavut.

"The Beverly herd’s crossing of the Thelon River to its traditional calving grounds near Beverly Lake was part of the lives of the Dene aboriginal people for 8 000 years, as revealed by an unbroken archaeological record of deep layers of caribou bones and stone tools in the banks of the Thelon River (Gordon 2005)."^[119][120] The Beverly Herd (located primarily in Saskatchewan, Northwest Territories; portions in Nunavut, Manitoba, Alberta) and the Qamanirjuaq Herd (located primarily in Manitoba, Nunavut; portions in southeastern NWT, northeastern Saskatchewan) fall under the auspices of the Beverly and Qamanirjuaq Caribou Management Board.^[121]

In 2011 the combined Beverly/Ahiak herd in the Northwest Territories and Nunavut, had approximately 124,000 caribou— at least a 50% drop since 1994; the Western caribou herd had 325 000 animals and the^[112][29] The Beverly herd, whose range spans the tundra from northern Manitoba and Saskatchewan and well into the Northwest Territories and Nunavut, had a peak population in 1994 of 276 000^[122][123] or 294 000,^[112] but by 2011 there were approximately 124 000 caribou in the Beverly herd and 83,300 in the Ahiak herd. The calving grounds of the Beverly caribou herd are located around Queen Maud Gulf but the herd shifted its traditional birthing area.^[124] Caribou management agencies are concerned that deterioration and disturbance of habitat along with "parasites, predation and poor weather"^[125] are contributing to a cycling down of most caribou populations. It was suggested the Ahiak and Beverly herds switched calving grounds and the Beverly may have moved "near the western Queen Maud Gulf coast to the north of the herd’s "traditional" calving ground in the Gary Lakes area north of Baker Lake."^[126] The "Beverly herd may have declined (similar to other Northwest Territories herds), and cows switched to the neighbouring Ahiak herd to maintain the advantages of gregarious calving."^[127] By 2011 there were approximately 124,000 caribou in the combined Beverly/Ahiak herd which represents a "50% or a 75% decline from the 1994 population estimate for the Beverly Herd."^[112]

Qamanirjuaq caribou herd which is relatively stable had declined from 496,000 in 1994 to 345,000 in 2008.^[8]

The barren-ground caribou population on Southampton Island, Nunavut declined by almost 75%, from about 30 000 caribou in 1997 to 7,800 caribou in 2011.^[112][128]

Dolphin-Union Caribou

The Dolphin-Union Caribou herd locally known as Island Caribou,^[129][130] are a migratory population of barren-ground caribou, Rangifer tarandus groenlandicus, that occupy Victoria Island in Canada's High Arctic and the nearby mainland. They are endemic to Canada. They migrate across the Dolphin and Union Strait from their summer grazing on Victoria Island to their winter grazing area on the Nunavut-NWT mainland in Canada.^[129][131] It is unusual for North American caribou to seasonally cross sea ice and the only other caribou to do so are the Peary caribou who are smaller in size and population.

Peary caribou

The Peary caribou is a relatively small and pale subspecies found in the tundra of far northern North America.

The R. t. pearyi (Peary caribou), the smallest of the species, known as Tuktu in Inuktitut, are found in the High Arctic of Nunavut and the Northwest Territories. The Peary caribou a Canadian endemic subspecies and appears to be of postglacial origin. They remain at low numbers after severe declines and all populations are listed as endangered by COSEWIC. On Baffin Island, the largest Arctic island, the population of Peary caribou peaked in the early 1990s to approximately 60 000 to 180 000.^[132] By 2012, in northern Baffin Island caribou numbers were considered to be at a "low in the cycle after a high in the 1990s" and in south Baffin Island, the population was estimated as between 1 065 and 2 067.^[133]

Northwest Territories

There are four barren-ground caribou herds in the Northwest Territories—Cape Bathurst, Bluenose West, Bluenose East and Bathurst.^[112] The Bluenose East caribou herd began a recovery with a population of approximately 122 000 in 2010.^[134] which is being credited to the establishment of Tuktut Nogait National Park.^[135] According to T. Davison 2010, CARMA 2011, the three other herds "declined 84-93% from peak sizes in the mid-1980s and 1990s.^[112]

R. t. caribou

The subspecies R. t. caribou commonly known as woodland caribou, is divided into ecotypes: boreal woodland caribou, (also known as forest-dwelling, woodland caribou (boreal), mountain woodland caribou and migratory woodland caribou). Caribou are classified by ecotype depending on several behavioural factors - predominant habitat use (northern, tundra, mountain, forest, boreal forest, forest-dwelling), spacing (dispersed or aggregated) and migration (sedentary or migratory).^{[82][109][110]}

In Canada, the national meta-population of the sedentary boreal ecotype spans the boreal forest from the Northwest Territories to Labrador. They prefer lichen-rich mature forests ^[136] and mainly live in marshes, bogs, lakes, and river regions.^[137][138] The historic range of the boreal woodland caribou covered over half of present-day Canada,^[139] stretching from Alaska to Newfoundland and Labrador and as far south as New England, Idaho, and Washington. Woodland caribou have disappeared from most of their original southern range. The boreal woodland was designated as threatened in 2002.^[10] In 2011 there were approximately 34 000 boreal caribou in 51 ranges remaining in Canada.^[140]

George River caribou herd (GRCH)

The migratory George River caribou herd (GRCH), in the Ungava region of Quebec and Labrador in eastern Canada was once the world's largest herd with 800 000–900 000 animals. Although it is categorized as a subspecies Rangifer tarandus caribou,^[98] the woodland caribou, the GRCH is migratory and like the barren-ground caribou it's ecotype may be tundra caribou, Arctic, northern of migratory, not forest-dwelling and sedentary like most woodland caribou ecotypes. It is unlike most woodland caribou in that it is not sedentary. Since the mid-1990s, the herd declined sharply and by 2010, it was reduced to 74,131—a drop of up to 92%.^[7] A 2011 survey confirms a continuing decline of the George River migratory caribou herd population. By 2014 the herd was estimated to be about to 14 200^[11] down from 27,600 in 2012, 74 131 in 2010 and 385 000 in 2001.^{[7][125][112]}

Leaf River caribou herd (LRCH)

• 

  Caribou crossing Leaf River

• 

  Leaf River and caribou

The Leaf River caribou herd (LRCH),^[141] another migratory forest-tundra ecotype of the boreal woodland caribou, near the coast of Hudson Bay, increased from 270 000 individuals in 1991 to 628 000 in 2001.^[142] By 2011 the herd had decreased to 430 000 caribou.^{[112][143][144]} According to an international study on caribou populations, the George River and Leaf River herds, and other herds that migrate from Nunavik, Quebec and insular Newfoundland, could be threatened with extinction by 2080.^[125]

Queen Charlotte Islands caribou

The extinct Queen Charlotte Islands caribou (R. tarandus dawsoni) from the Queen Charlotte Islands was believed to represent a distinct subspecies. It became extinct at the beginning of the 20th century. However, recent DNA analysis from mitochondrial DNA of the remains from those reindeer suggest that the animals from the Queen Charlotte Islands were not genetically distinct from the Canadian mainland reindeer subspecies.^[145]

Alberta

In Alberta's northwestern foothills, an area disturbed by decades of industrial development by the energy industry, the federal government set a target of leaving 65% of the habitat of the Little Smoky and a la Peche caribou herds undisturbed. By 2014 only 5% of their habitat remained undisturbed; the rest was crisscrossed with 16,000 kilometres of seismic lines cut for industry-related geological research in one 13,000 square kilometres section alone of these foothills.^[146] and with bush roads, access roads connecting clearcuts and well pads. While clearly visible from an aerial view-such as is provided by Google Earth-and from the back roads, the deforestation and devastation is veiled by a curtain of forest that runs along the highways. Caribou depend on the cover of the forest for protection from wolf predation but the seismic lines destroy the places they usually hide. Wolves usually prefer to hunt moose and deer than the elusive, stealthy and fast-running caribou and their natural and ancient hunter/predator relationship was managed by the ecosystem itself. But seismic lines have destroyed the advantage they once had. Federal and provincial governments concerned about sustainable development and restoration, are waiting for the conclusion of the three-year study (2014-2017) undertaken by the Foothills Research Institute in Hinton, Alberta on human and animal land use in this area.^[146] This study has already shown that the height of vegetation on the seismic trails may be one of the most contributing factors. As the height of vegetation decreased, the number of human motorized use-snowmobiles, Quads and ATV for example- increased. The lower the vegetation the harder it was for caribou to evade wolves.^[146]

According to the Alberta Caribou Committee, new and innovative industrial methods at the time of development will prevent degradation of habitat. For example, habitat is restored more rapidly with narrow (1.5-2.5) meandering seismic lines than traditional wide (8-m) straight lines. It is now possible to reduce or eliminate roads by using remote monitoring techniques for some types of oil and gas well sites.^[147]

Conservation and recovery

Ongoing human development of caribou habitat has caused populations of woodland caribou to disappear from their original southern range. In particular, the caribou was extirpated in many areas of eastern North America in the beginning of the 20th century. Woodland caribou was designated as threatened in 2002.^[10] Environment Canada reported in 2011 that there were approximately 34 000 boreal caribou in 51 ranges remaining in Canada (Environment Canada, 2011b).^[148] Professor Marco Musiani of the University of Calgary, said in a statement that "The woodland caribou is already an endangered species in southern Canada and the United States....[The] warming of the planet means the disappearance of their critical habitat in these regions. Caribou need undisturbed lichen-rich environments and these types of habitats are disappearing."^[149]

Woodland caribou have disappeared from most of their original southern range and was designated as threatened in 2002 by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC).^[10] Environment Canada reported in 2011 that there were approximately 34 000 boreal caribou in 51 ranges remaining in Canada.(Environment Canada, 2011b).^[148] "According to Geist, the "woodland caribou is highly endangered throughout its distribution right into Ontario."^[5]

In 2002 the Atlantic-Gaspésie population of the woodland caribou was designated as endangered by COSEWIC. The small isolated population of 200 animals was at risk from predation and habitat loss.

In 1991 COSEWIC assigned "endangered status" to the Banks Island and High Arctic populations of Peary caribou. The Low Arctic population of Peary caribou was designated as threatened. By 2004 all three were designated as "endangered."^[150] In spite of voluntary hunting quotas—for example in Sachs Harbour—This caribou is a Canadian endemic subspecies.

Numbers have declined by about 72% over the last three generations, mostly because of catastrophic die-off likely related to severe icing episodes. The ice covers the vegetation and caribou starve. Voluntary restrictions on hunting by local people are in place, but have not stopped population declines. Because of the continuing decline and expected changes in long-term weather patterns, this subspecies is at imminent risk of extinction.

— COSEWIC 2004

According to IUCN Rangifer tarandus as a species is not endangered because of its overall large population and the widespread range.^[1] However, in North America subspecies R. t. dawsoni is extinct.^{[150][145][151]} R. t. pearyi is endangered, R. t. caribou are designated as threatened and some individual populations are endangered. While the subspecies R. t. granti and R. t. groenlandicus are not designated as threatened, many individual herds—including some of the largest—are declining and there is much concern at the local level.^[112]

Rangifer tarandus is "endangered in Canada in regions such as south-east British Columbia at the Canadian-USA border, along the Columbia, Kootenay and Kootenai rivers and around Kootenay Lake. Rangifer tarandus is endangered in the United States in Idaho and Washington.

There is strong regional variation in Rangifer herd size, By 2013 many caribou herds in North America had "unusually low numbers" and their winter ranges in particular were smaller than they used to be.^[112] Caribou numbers have fluctuated historically, but many herds are in decline across their range.^[152] There are many factors contributing to the decline in numbers.^[153]

Relationship with humans

Humans started hunting caribou in the Mesolithic and Neolithic periods.

Rangifer tarandus hunting by humans has a very long history, and they "may well be the species of single greatest importance in the entire anthropological literature on hunting."^[154] "In North America and Eurasia the species has long been an important resource—in many areas 'the' most important resource—for peoples inhabiting the northern boreal forest and tundra regions. Known human dependence on caribou/wild reindeer has a long history, beginning in the Middle Pleistocene^[155][156] and continuing to the present.... The caribou/wild reindeer is thus an animal that has been a major resource for humans throughout a tremendous geographic area and across a time span of tens of thousands of years."^[154]

In the traditional lifestyle of the Inuit people, in particular the Caribou Inuit, Northern First Nations people, Alaska Natives, the caribou is an important source of food, clothing, shelter, and tools.

The caribou vadzaih is the cultural symbol and a keystone subsistence species of the Gwich'in, just as the buffalo is to the Plains Indians.^[157] Innovative language revitalization projects are underway to document the language, and to enhance the writing and translation skills of younger Gwich'in speakers. In one project lead research associate and fluent speaker Gwich’in elder, Kenneth Frank, works with linguists which include young Gwich'in speakers affiliated with the Alaska Native Language Center at the University of Alaska in Fairbanks to document traditional knowledge of caribou anatomy.^[157] Elders have identified at least 150 descriptive Gwich'in names for all of the bones, organs, and tissues "Associated with the caribou's anatomy are not just descriptive Gwich'in names for all of the body parts including bones, organs, and tissues as well as "an encyclopedia of stories, songs, games, toys, ceremonies, traditional tools, skin clothing, personal names and surnames, and a highly developed ethnic cuisine."^[157]

First Nations and Inuit oral histories

There is an Inuit saying from the Kivalliq region,^[158]

The caribou feeds the wolf, but it is the wolf who keeps the caribou strong.

— Kivalliq region

Elder Chief of Koyukuk and chair for the Western Arctic Caribou Herd Working Group, Benedict Jones or K’ughto’oodenool’o’ represents the of the Middle Yukon River, Alaska. His grandmother was a member of the Caribou Clan, who travelled with the caribou as a means to survive. In 1939, they were living the traditional life style at one of their hunting camps in Koyukuk near the location of what is now the Koyukuk National Wildlife Refuge. His grandmother made a pair of new mukluks in one day. K’ughto’oodenool’o’ recounted story told by an elder, who "worked on the steamboats during the gold rush days out on the Yukon." In late August the caribou migrated from the Alaska Range up north to Huslia, Koyukuk, and the Tanana area. One year the steamboat was unable to continue they ran into a caribou herd numbering estimated at a million animals, migrating across the Yukon. "They tied up for seven days waiting for the caribou to cross. "They ran out of wood for the steamboats, and had to go back down 40 miles to the wood pile to pick up some more wood. On the tenth day, they came back and they said there was still caribou going across the river night and day."^[29]

In mythology and art

Among the Inuit, there is a story of the origin of the caribou,^[159]

Once upon a time there were no caribou on the earth. But there was a man who wished for caribou, and he cut a hole deep in the ground, and up this hole came caribou, many caribou. The caribou came pouring out, until the earth was almost covered with them. And when the man thought there were caribou enough for mankind, he closed up the hole again. Thus the caribou came up on earth.

— Canada's Arctic 2002a

Inuit artists from the barren lands, incorporate depictions of caribou—and items made from caribou antler and skin— in carvings, drawings, prints and sculpture.

Contemporary Canadian artist Brian Jungen's, of Dunne-za First Nations ancestry, commissioned installation entitled "The ghosts on top of my head" (2010–11) in Banff, Alberta, depicts the antlers of caribou, elk and moose.^[160]

I remember a story my Uncle Jack told me – a Dunne-Za creation story about how animals once ruled the earth and were ten times their size and that got me thinking about scale and using the idea of the antler, which is a thing that everyone is scared of, and making it into something more approachable and abstract.

— Brian Jungen 2011

Tomson Highway, CM^[161] is a Canadian and Cree playwright, novelist, and children's author, who was born in a remote area north of Brochet, Manitoba.^[161] His father, Joe Highway, was a caribou hunter. His 2001 children's book entitled Caribou Song/atíhko níkamon was selected as one of the "Top 10 Children’s Books" by the Canadian newspaper The Globe and Mail. The young protagonists of Caribou Song, like Tomson himself, followed the caribou herd with their families.

Canadian icon

The Canadian 25-cent coin, or "quarter" features a depiction of a caribou on one face. The caribou is the official provincial animal of Newfoundland and Labrador, Canada, and appears on the coat of arms of Nunavut. A caribou statue was erected at the center of the Beaumont-Hamel Newfoundland Memorial, marking the spot in France where hundreds of soldiers from Newfoundland were killed and wounded in the First World War and there is a replica in Bowring Park, in St. John's, Newfoundland's capital city.^[162] The caribou is also the symbol of Newfoundland's Qalipu Mi'kmaq First Nation Band founded in 2009. As noted above, the word caribou is derived from the Mi'kmaw term qalipu (prounced kah- li -bu).

See also

• List of Wildlife Species at Risk (Canada)
• Rangifer (journal)
• Rangifer (constellation)
• Hypoderma tarandi
• Cephenemyia trompe

Notes

1. According to Inuit elder, Marie Kilunik of the Aivilingmiut, Canadian Inuit preferred the caribou skins from caribou taken in the late summer of fall when their coats had thickened. They used for winter clothing "because each hair is hollow and fills with air trapping heat."(Marie Kilunik, Aivilingmiut, Crnkovich 1990:116).
2. The Integrated Taxonomic Information System list Wilson and Geist on their experts panel.
3. The George River and Leaf River caribou herds are classified as woodland but are also migratory with tundra as their primary range
4. Grubb (2005) argued that these North American the R. t. dawsoni subspecies in the woodland caribou division, that the R. tarandus osborni subspecies in the "Populations transitional between caribou and tarandus division" and the subspecies R. t. caboti, R. t. groenlandicus, R. t. pearsoni and R. t. terraenovae in the Tarandus division, barren-ground caribou and the subspecies R. t. pearyi in the Platyrhynchus division should be considered valid based on Banfield (Banfield) and considerably modified by Geist (1998).

• Banfield rejected this classification in 1961. However, Valerius Geist and others considered it valid.

Further reading

• "Caribou Census Complete: 325,000 animals" (PDF), Caribou Trails: News from the Western Arctic Caribou Herd Working Group (Nome, Alaska: Western Arctic Caribou Herd Working Group), August 2012, retrieved 14 January 2014 This 15 page well-illustrated and highly informative August 2012 edition of the Western Arctic Caribou organization newsletter, reported the 2011 census results of the WACH, which is Alaska's largest caribou herd.

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External links

• Species at Risk in Canada Registry
• List of Species at Risk in Canada, by category
• Species at Risk in Canada at Hinterland Who's Who
• Frequently Asked Questions about Caribou from the Arctic National Wildlife Refuge
• Caribou and You – Campaign by CPAWS to protect the woodland caribou, a species at risk in Canada
• Newfoundland Five-Year Caribou Strategy Seeks to Address Declining Populations
• Rangifer tarandus on the IUCN Red List

Reindeer herding and husbandry in North America

• Reindeer Research Program - Alaska reindeer research and industry development
• Adaptations To Life In The Arctic –Instructional slide-show, University of Alaska
• Rangifer – world's only scientific journal dealing exclusively with husbandry, management and biology of Arctic and northern ungulates
• 1935 Reindeer Herding in the Northwest Territories
• General information on Caribou and Reindeer
• Human Role in Reindeer/Caribou Systems
• Works related to Caribou at Wikisource