Reindeer

Reindeer, sometimes known as caribou in North America, is a circumpolar deer species native to northern Europe, Siberia, and North America's Arctic, subarctic, tundra, boreal, and mountainous regions. The Svalbard reindeer is the smallest, while the large reindeer is the boreal forest caribou. Real reindeer range in North America stretches from Alaska to the Yukon, Northwest Territories, and Nunavut, then south through the Canadian Rockies and the Columbia and Selkirk Mountains to the boreal forest.

Taxonomy of Reindeer

• The kingdom of reindeer is Animalia.

• The reindeer phylum is Chordata.

• Reindeer belongs to the class Mammalia.

• Their order is Artiodactyla.

• The Reindeer family is Cervidae and the subfamily is Capreolinae.

• Reindeer belong to the tribe Rangiferini.

• The genus of reindeer is Rangifer.

• The scientific name of reindeer is Rangifer tarandus.

• The male reindeer is called a bull, the female reindeer is called a cow and the baby reindeer called a calf.

For the reindeer genus, Carl Linnaeus adopted the name Rangifer, which Albertus Magnus used in his De animalibus. Although the names reindeer and caribou are sometimes used interchangeably to refer to the same species, the International Union for Conservation of Nature explicitly defines the difference. Rangifer tarandus is the name given to the world's caribou and reindeer species. Reindeer is the European name for the species, whereas Caribou is the North American term. The word rein comes from the Norse language. The word deer had a broader meaning at first, but as time went on, it became more particular.

Characteristics of Reindeer

• Both male and female reindeer antlers sprout in most populations. Reindeer are the only cervid species in which females and males both develop antlers.

• Androgens play a crucial function in cervid antler development. In comparison to other cervids, reindeer antlerogenic genes are more sensitive to androgens.

• The size of the antlers varies greatly between subspecies, but on average, behind the moose, the bull reindeer's antlers are the second largest of any existing animal.

• Large males' antlers can measure up to 100 cm in breadth and 135 cm in beam length in the biggest subspecies. Among surviving deer species, they have the largest antlers in proportion to their body size.

• The number of points on the reindeer's antlers represents the reindeer's nutritional level as well as the climate variance in its environment.

• From birth to five years of age, the number of points on male reindeer grows and then stays pretty steady. Antler mass in male caribou varies in tandem with body mass.

• The primary beams of the antlers start at the brow and extend posteriorly across the shoulders, bowing forward with the tips pointing forward. The palmate brow tines protrude forward and over the face. The points on antlers are usually divided into two groups: lower and upper.

• During the mating season, male reindeer utilise their antlers to compete with other males. The majority of the mating is done by huge males with large antlers. Reindeer will continue to travel until the bull reindeer's back fat is depleted.

• Male reindeer lose their antlers after the rut in late fall or early winter and develop a new pair the following summer with a larger rack than the previous year. Reindeer females preserve their antlers until they give birth.

• When bull reindeer shed their antlers in early to midwinter, antlered female reindeer rise to the top of the feeding hierarchy and obtain access to the greatest grazing locations. These cows are in better health than those who don't have antlers.

• Calves whose mothers lack antlers are more susceptible to sickness and have a greater mortality rate.

• The colour of the fur varies greatly, depending on the season and subspecies, as well as across individuals.

• Northern populations, which are normally tiny, are whiter, whereas southern populations, which are typically huge, are darker.

• This is particularly evident in North America, where the northernmost subspecies, the Peary caribou, is the whitest and smallest of the continent's subspecies, while the boreal woodland caribou is the darkest and largest.

• The fur is divided into two layers: a dense woolly undercoat and a longer-haired topcoat with hollow, air-filled hairs.

• Even if the temperature climbs to 38 °C (100 °F), the key insulation factor that permits reindeer to manage their core body temperature in relation to their environment, the thermogradient, is fur.

• Reindeer have a countercurrent heat exchange (CCHE) system, where blood going into the legs is cooled by blood returning to the body, resulting in a highly efficient method of reducing heat loss via the skin's surface.

• CCHE is found in animals such as reindeer, foxes, and moose that live in extreme cold or hot weather as a mechanism for preserving body heat. These are countercurrent exchange systems that employ the same fluid, usually blood, in both directions of flow in a circuit.

• Blood vessels are tightly knotted and interwoven with arteries reaching the skin and appendages that carry warm blood and veins returning to the body that carries cold blood in the CCHE mechanism, forcing the heated arterial blood to exchange heat with the cold venous blood. In this way, their legs stay cool, allowing them to keep their core body temperature roughly 30 °C (54 °F) higher while losing less heat to the environment. Instead of being dissipated, heat is regenerated.

• To keep a consistent body core temperature and consequently metabolic rate, the heart of reindeer does not have to pump blood as quickly. 

• Reindeer's nasal passages feature specialised counter-current vascular heat exchange. Physiological control of the temperature gradient along the nasal mucosa. Before the reindeer's breath is exhaled, the arriving cold air is warmed by body heat, and water is condensed from the expired air and caught, then used to moisten dry incoming air and possibly taken into the blood through the mucous membranes.

• For walking in snow or swamps, the reindeer has broad feet with crescent-shaped cloven hooves.

• The footpads of reindeer hooves turn sponge-like in the summer, when the tundra is soft and wet, and give extra traction.

• The pads shrink and tighten in the winter, exposing the hoof's rim, which cuts into the ice and crusted snow to prevent slipping. This also allows them to dig their way down through the snow to their favourite food, reindeer lichen.

• Females average 162–205 cm in length and 80–120 kg in weight.

• Males are larger, averaging 180–214 cm in length and weighing 159–182 kg on average.

• Shoulder height ranges from 85 to 150 cm, with a tail length of 14 to 20 cm.

• The Svalbard reindeer are the tiniest. They are also short-legged, with shoulder heights as low as 80 cm.

• Many real reindeer subspecies have altered their knees to make a clicking sound when they walk. The sounds originate in the knee tendons and can be heard from hundreds of metres distant. 

• The frequency of the knee clicks is one of a number of signals that reindeer use to determine their relative dominance on a dominance scale.

• Reindeer can perceive UV light with wavelengths as short as 320 nm, which is well below the human threshold of 400 nm.

• Many items that blend into the terrain in visible light, such as urine and fur, exhibit dramatic contrasts in ultraviolet light, which is thought to help them survive in the Arctic.

• The tapetum lucidum of Arctic reindeer eyes changes colour from gold to blue in the winter to increase their eyesight during periods of constant darkness, possibly allowing them to see predators more easily.

• Reindeer have evolved characteristics that allow them to have optimal metabolic efficiency in both warm and cold months.

• Reindeer body composition changes dramatically with the seasons. The body composition and diet of breeding and non-breeding females between seasons is of particular interest.

• Between the months of March and September, breeding females have slightly greater body mass than non-breeding females, with a difference of roughly 10 kg.

• Non-breeding females have more body mass in November and December than breeding females, as non-breeding females are able to focus their resources on storage rather than breastfeeding and reproduction during the colder months.

• In September, the body mass of both breeding and non-breeding females reaches its highest point.

• Breeding females had around three kilogrammes greater fat mass than non-breeding females throughout the months of March and April. Non-breeding females, on the other hand, have a larger fat mass than breeding females.

• Winter diet is critical to adult and newborn survival rates, hence environmental variables play a big role in reindeer nutrition. Lichens are a wintertime staple because they are a readily available food supply that decreases the need to rely on stored body reserves.

• Lichens are an important part of the reindeer diet, but they are less common in the diets of pregnant reindeer than in the diets of non-pregnant reindeer.

• Due to the lack of nutritional value, lichen is found more frequently in non-pregnant adult diets than in pregnant female's diets.

• Lichens are high in carbohydrates, but they lack the necessary proteins found in vascular plants.

• The amount of lichen in a diet decreases with latitude, resulting in greater nutritional stress in places where lichen is scarce.

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Reproduction and Life Cycle of Reindeer

• Reindeer mate between late September and early November, with a gestation period of 228–234 days.

• Males compete for access to females throughout the mating season. Two males will try to push each other away by locking their antlers together.

• Males with the most dominance can amass as many as 15–20 females to mate with. During this stage, a male will cease eating and shed a significant amount of body fat.

• Females seek out remote, predator-free habitats to calve, such as islands in lakes, peatlands, lakeshores, or tundra. Females are more cautious than males when choosing a location for the birth of their calves.

• The average weight of a newborn is 6 kg. The calves are born in May or June. The calves are ready to graze and forage after 45 days, but they must continue to nurse until the following autumn when they are no longer dependent on their moms.

• Males have a four-year less life expectancy compared to females, who have a maximum lifespan of roughly 17 years. Females with regular body size and adequate summer nourishment can start breeding between the ages of one and three years.

Distribution, Habitat and Diet of Reindeer

• The reindeer was once located north of the 50th latitude in Scandinavia, eastern Europe, Greenland, Russia, Mongolia, and northern China.

• It was found in Canada, Alaska, and the northern conterminous United States, from Washington to Maine, in North America.

• Reindeer were found further south throughout the late Pleistocene era, in places like Nevada, Tennessee, and Alabama in North America, and as far south as Spain in Europe. 

• Today, wild reindeer have vanished from these places, particularly in the south, where they have vanished virtually entirely. Norway, Finland, Siberia, Greenland, Alaska, and Canada all have large numbers of wild reindeer.

• Reindeer have a four-chambered stomach, making them ruminants. They eat lichens mostly in the winter, especially reindeer lichen. They are the only large mammal capable of metabolising lichen due to specialised bacteria and protozoa in their intestines.

• Except for some gastropods, they are the only animals in which the enzyme lichenase, which converts lichenin to glucose, has been discovered. They do, however, eat willow and birch leaves, as well as sedges and grasses.

• They have been observed to consume their own antlers that have fallen to the ground, most likely for calcium.

• Reindeer modify their sleeping schedule from one synchronised with the sun to an ultradian cycle in which they sleep when they need to digest food during the Arctic summer when there is continuous sunshine.

• Reindeer are preyed upon by a number of predators, including overhunting by humans in some places, which leads to population reduction.

• Golden eagles are the most common predator of calves on the calving grounds.

• Wolverines will consume newborn calves or cows in the process of giving birth, as well as infirm adults.

• Brown bears and polar bears prey on reindeer of all ages, but they are more prone to attack weaker animals, such as calves and sick reindeer, than robust adult reindeer, as are wolverines.

• The grey wolf is the most effective natural predator of adult reindeer, taking significant numbers of them at times, particularly during the winter. Some wolf packs, as well as individual grizzly bears in Canada, may year-round follow and feed on a specific reindeer herd.

• Reindeer may also be scavenged opportunistically by foxes, hawks, and ravens as carrion.

Reindeer Husbandry

• The reindeer is the world's sole domesticated deer, but it's probably more true to call them semi-domesticated.

• All semi-wild domestic reindeer in northern Norway, Sweden, and Finland, as well as the Kola Peninsula and Yakutia in Russia, are ear-marked by their owners.

• Some reindeer in the area have been tamed and are used mostly as draught animals.

• Reindeer are widely used for tourist entertainment and races nowadays, but they were historically vital to the nomadic Sami.

• In Norway, domesticated reindeer have also been used to produce milk.

• Reindeer are commonly used for transportation among the nomadic peoples of northern Russia.

Santa Claus's Reindeer

• Santa Claus' reindeer are thought to draw a sleigh through the night sky to enable Santa Claus to deliver gifts to children on Christmas Eve, according to legend in several regions of the world. Dasher reindeer, Dancer, Prancer, Vixen, Comet, Cupid, Donner, Blitzen, and Rudolph are the names of all of Santa’s reindeer. Dasher reindeer is the eldest of all of Santa’s reindeer.

• The first eight reindeer are based on those in Clement Clarke Moore's 1823 poem A Visit from St. Nicholas, also known as The Night Before Christmas. This poem is most likely responsible for the reindeer's popularity.

• Moore's eight reindeer, plus Rudolph, who was introduced in a 1939 storybook and later the subject of a hit song and television special, has been widely accepted in popular culture since the mid-twentieth century.

Conclusion

Reindeer and caribou are both members of the deer family and are the same animal. Reindeer is the name given to them throughout Europe. If the animals are wild, they are called caribou, and if they are domesticated, they are called reindeer in North America. Reindeer are the only deer species with hair that covers their entire snout. Their unique nose aids in the warming of entering cold air before it enters their lungs, and it also functions as a great sniffer. Reindeer herds of 10 to a few hundred migrate, graze and rest together throughout the day. The only deer species that has been widely tamed is the reindeer. They are utilised as pack animals and are raised for milk, meat, and hides.