Buzz
In North America, the term 'reindeer' refers to a domesticated species of deer often associated with humans (and Santa Claus). The word 'caribou' refers to a type of wild deer found in the Arctic and subarctic regions. Despite the different names, both animals belong to the same species, Rangifer tarandus.
While people outside the natural habitats of reindeer might only think of them during the Christmas season, for others, reindeer are integral to everyday life. Below are some obscure, unusual, and even repulsive facts about reindeer.
10. Differences Between Domestic and Wild Reindeer
Estimates vary on when reindeer were first domesticated. In Eurasia, it's believed that domestication occurred roughly 7,000 years ago. Other sources suggest it happened around 2,000 to 3,000 years ago.
Although reindeer have been domesticated for a long time, they are still considered only semi-domesticated for two reasons. First, reindeer have not undergone significant artificial selection until recent times. Second, human-kept reindeer often interbreed with wild reindeer since domesticated herds are rarely enclosed and live close to wild populations.
There are some noticeable differences between the bodies of semidomestic and wild reindeer. Semidomestic reindeer tend to be slightly smaller and have shorter snouts. They also display more variation in color. While wild reindeer populations exhibit color differences, the variation is even greater within domesticated herds, which can even include occasional pinto reindeer.
Until recently, reindeer were heavily milked in a region of Russia west of Lake Baikal. In this area, domesticated reindeer are said to have udders 25 percent larger than those of their wild counterparts.
Domestic and wild reindeer also differ in behavior. Compared to wild reindeer, domesticated ones mate and give birth about a month earlier, are less motivated during migration, and have lower endurance. More noticeably, domestic reindeer are much tamer, more tolerant of humans, and can be easily trained.
9. Extreme Temperatures in the Arctic
Reindeer have relatively long legs that aid in migration and escaping from predators. However, the length of these legs can increase the risk of heat loss. To combat this, reindeer have a unique arrangement of blood vessels. The warm blood flowing into the legs passes closely by the cold blood returning from them, allowing for some heat exchange. This process ensures that very little heat is lost from the legs.
Inside their noses, reindeer possess bone and cartilage structures called 'conchae,' which resemble rolled-up scrolls. These conchae are covered with a mucous membrane rich in blood vessels.
As cold air enters a reindeer’s nose, it flows over the warm mucous membrane, raising it to body temperature. This process causes the air to become saturated with water vapor as it moves toward the lungs. The vapor then flows into special folds that direct it toward the back of the nose and down into the throat.
When a reindeer exhales, the warm, humid air passes over a temperature gradient as it moves over the cold mucous membrane. This causes the air to cool and the water vapor to condense. As a result, unlike most mammals, the air exhaled by reindeer is cold and relatively dry.
8. Flies in Reindeer Noses
During July and August, reindeer may suddenly shake their heads violently, stomp their feet, and race across the tundra without any apparent reason. This behavior is a defense against parasitic flies, including the bot fly Cephenemyia trompe. Unlike most flies, the fluffy, bee-like C. trompe does not lay eggs but injects tiny maggots directly into the reindeer’s nose.
The larvae grow within the reindeer’s nasal passages for a while before burrowing deeper into the sinuses and throat. By spring, they may have grown large enough to form a mass that interferes with the reindeer’s breathing. In severe cases of C. trompe infestation, there could be over 50 larvae inside the reindeer’s nose, and the animal could suffocate.
Once fully matured, the larvae crawl back into the nasal passages, where they are expelled through sneezing or coughing. Afterward, the maggots burrow into the ground, where they spend the winter before transforming into adult flies.
By the time the flies emerge, the reindeer herd has moved on. However, this does not pose a problem for the flies. Their antennae are sensitive to the scent of reindeer urine and the pheromones released between the reindeer’s hooves. The flies can follow this scent trail and track reindeer for over 48 kilometers (30 miles).
7. Antlers
To sport antlers in December, Santa’s reindeer must meet one of three criteria: they must be female, castrated, or immature. This is because mature, intact male reindeer shed their antlers in autumn, while other types of reindeer retain them throughout the winter.
Reindeer are the only species of deer where females have antlers. This has long been a source of intrigue. Growing and shedding antlers each year seems like an impractical task, especially in the harsher climates where reindeer reside.
It was once proposed that female reindeer grow antlers to defend themselves from predators. However, since reindeer shed their antlers annually, this would leave the females defenseless for the four to five months it takes for new antlers to grow.
It’s more likely that female reindeer have antlers to defend themselves from their own species rather than predators. In the winter, when food is limited, reindeer must dig through snow to find lichen, their primary food source. These reindeer then protect their food pits from others who might try to steal it.
Mature females, unlike mature males, retain their antlers throughout winter. This allows the females to better defend their lichen pits from larger but antlerless adult males.
There is an advantage to the males losing their antlers earlier in the season. Since reindeer are often pregnant in the winter, females require additional nourishment. By giving the females more food, their developing young have a better chance of surviving until birth in the spring.
6. Birth Control Shots for Male Reindeer
The behavior of male reindeer, or bulls, undergoes significant changes during the rut (mating season). During this period, they become aggressive, destructive, and dangerous, posing a threat to both handlers and other reindeer.
The rut season takes a toll on a male reindeer’s health, causing him to lose as much as 35 percent of his body weight despite being in a dominant position or near female reindeer. Additionally, maintaining enough male reindeer within a herd behind a fence requires a significant investment and a high level of skill to transition the animals through the post-rut phase.
To manage the behavioral effects of the rut, reindeer breeders have turned to Depo-Provera, a birth control drug. Ideally, the reindeer bulls receive their first Depo-Provera injection on the first day they begin shedding their antler velvet, which is seen as the early indication of rut. Bulls on the drug still mate, but tend to show less aggression.
Furthermore, bulls that have received these annual drug injections from a young age tend to live longer lives. Male reindeer typically live for 7-8 years, while females can reach 14-18 years. The difference is believed to be due to the extreme hormonal levels in the bulls’ bodies during mating season, which can lead to heart failure once they go into rut. Bulls treated with Depo-Provera have been known to survive until the age of 12.
5. Reindeer Noises
Male deer from various species make unique calls during the mating season, but reindeer stand out due to an air sac near their windpipe that aids in this vocalization. This sac inflates when males emit guttural, rattling calls, which help attract females and drive away other males.
Reindeer are born without an air sac, which gradually develops as they grow. In their early years, both males and females grow their air sacs similarly. However, around the age of 2-3 years, the sac stops growing in females, while it continues to expand in males until they are about six years old, creating a noticeable size difference between the sexes.
In male reindeer, the air sac is asymmetrical, extending either to the left or right beneath the neck. As rut begins, the diameter of a male’s neck expands due to increased muscle mass. At the same time, males grow a beard-like mane around the air sac’s location. During calls, this mane spreads out, providing a visual display.
4. Eating Lichen
Reindeer are quite unique among mammals for their heavy consumption of lichen, which makes up 60–70 percent of their winter diet. Depending on the species, they can digest 40–90 percent of the organic matter in lichens, a much higher efficiency than sheep and cows, who can only digest a smaller fraction.
Like sheep and cows, reindeer are ruminants, possessing multiple stomach compartments. The first stomach, the rumen, is home to bacteria that, along with the reindeer's own digestive enzymes, help break down the tough lichen they consume.
Though lichen is rich in carbohydrates, it is extremely low in protein and minerals. Without an additional nitrogen source, reindeer in captivity would lose weight on a strictly lichen-based diet.
To cope with the low-protein content of their diet, reindeer have developed a clever method. Their kidneys concentrate urea, a nitrogen-rich waste product, which is then recycled into the rumen. In the rumen, bacteria use the urea and fermentable carbohydrates (lichen) to synthesize protein. Remarkably, 71 percent of the urea produced in winter is recycled into the digestive system.
3. Reindeer Love Human Urine
Reindeer suffer from a salt deficiency in their diet. Along coastal areas, they obtain salt by drinking seawater or licking salt deposits on beaches. However, farther inland, salt is much harder to find. Like other deer, reindeer are naturally attracted to salt, but they are particularly drawn to human urine, which contains a high amount of salt.
The Inupiat people of Alaska have exploited this attraction by using human urine as bait for pitfall traps. The strong smell of the urine lures passing reindeer, who venture close enough to fall into the trap, where spikes await them.
The Tozhu Tuvan (or Tozhu) people in Tuva, Russia, take this practice further. Although these reindeer are domesticated, they still forage independently and live similarly to their wild counterparts.
So, what keeps these reindeer manageable and under control? It's urine.
Urine and salt are offered to the reindeer as a way to encourage them to return to the Tozhu campsites. Although reindeer are naturally wary of human scent, they are trained to associate humans with the salt they crave, which leads them to seek out the humans.
Tozhu men frequently urinate near their homes, often on a hollow tree stump or a specially designed tree-trunk urinal made for the reindeer. In the winter, the urine freezes almost instantly and is stored in these urinals, making it easy for the reindeer to lick it when they arrive at the campsite. Some reindeer are so fond of human urine that they will immediately gather around or even run toward a Tozhu man who appears to be preparing to urinate.
2. Reindeer Are Fond Of Their Own Urine
A reindeer’s preference for urine is not exclusive to humans. Like other species of deer, both male and female reindeer rub their hind legs together as they urinate, causing urine to spray into the air while simultaneously depositing its components into their hocks for later use as a signaling mechanism.
During the rut, the urine on a male reindeer’s hind legs serves as a scent marker to other reindeer. This is believed to happen because the male is the dominant figure within his mobile territory, and the scent, linked to aggression and dominance, typically brings an end to any aggressive encounters.
Reindeer don't just urinate on themselves. Male reindeer will dig into the soil, urinate on it, and then proceed to rub their noses in the urine for at least 10 minutes. Female reindeer also engage in this behavior, rubbing their noses in these urine patches.
1. A Diet Of Droppings
Spitsbergen, the only permanently inhabited island in Svalbard, located in northern Norway, experiences a harsh winter lasting for eight months. It is one of the most inhospitable regions on Earth. During these long winters, reindeer on the island sustain themselves by feeding on a meager selection of low-quality plants like mosses. Interestingly, they've adapted to this tough environment by incorporating an unusual food source—goose droppings—into their diet.
In the summer months, barnacle geese live near the lakes of Spitsbergen, consuming nearly all the available grass and some moss. However, their digestive systems struggle to process cellulose. Unlike them, reindeer have the ability to break down cellulose with the aid of microbes in one of their stomachs.
Reindeer are quite selective when it comes to food. In one study, they were found to prefer goose droppings that contained pieces of grass over those that had moss. During their regular resting times, geese would leave behind piles of 6–8 droppings. Researchers observed several occasions where reindeer chased the geese away in order to feast on these droppings.
The study estimated that 6–8 reindeer could survive on the goose droppings during the two months the geese were present. As a result, these droppings could serve as a significant supplementary food source for a few reindeer.
