Nottingham: We all know that Santa Claus would have a hard time delivering gifts to everyone in the world without the help of his magical reindeer. But why were they chosen to pull the sled rather than any other animal? It turns out that the biology of reindeer makes them ideal for the job. Here are five reasons why.
Heat: Reindeer live in the Arctic, where temperatures on long winter nights often drop below -30 ° C. Unlike most mammals, which have only one coat of fur, reindeer have two: a dense undercoat under a blanket of hollow guard hairs. Reindeer can have up to 2,000 hairs crammed into a single square inch, making it ten times denser than a human hair.
This double layer traps air and creates an insulating blanket that prevents reindeer from losing heat and keeps snow from reaching and cooling the skin. This allows the reindeer to warm up, whether they are living with Santa Claus at the North Pole or traveling the world on Christmas Eve.
Also, when the blood reaches our extremities, like our fingers and toes, it cools and our hearts have to pump at a faster rate to warm the blood again. It takes a lot of energy that we get from food, which is often lacking in arctic landscapes – well, unless you’re going to feast on candy canes and sugar plums with the elves.
But reindeer have what’s called countercurrent heat exchange that essentially allows them to recycle heat so the heart doesn’t have to work as hard. The arteries and veins carrying blood to and from the heart are intertwined, allowing heat from warm arterial blood to pass to cold venous blood.
Much of this heat exchange occurs in the specialized nasal bones of the reindeer, where a lot of cold air is inhaled through the nostrils. In fact, the highly concentrated blood vessels in their nostrils often give reindeer a red nose, just like Rudolph.
Aptitude: Reindeer lichen – an organism formed from a symbiotic relationship between algae and fungi – is the main thing reindeer eat during the winter. Lichens are the crispy things you often see living on tree trunks and rocks.
Lichens are abundant in the Arctic – an ideal food source that reindeer can find wherever they go. This means that reindeer don’t need to store body fat and, unlike many other animals, they can find enough food to fuel their epic sleigh journey with Santa Claus – aided by the carrots that the people leave out, of course. Reindeer are in fact the only mammals capable of digesting lichen, thanks to specialized bacteria present in their intestines.
View: The Arctic has very little daylight during winter, so reindeer have evolved to see as much as possible in the dark. Reindeer eyes change color from gold to blue in winter, letting in more of the small amount of light available and improving their vision.
Reindeer can even see in the ultraviolet light. Although this astonishing sense is common in birds and insects, reindeer are among the only mammals to have developed this ability. This means that objects that would blend into the background when seen through human eyes are much more visible to reindeer.
Since reindeer can essentially see in the dark, this makes them perfect for guiding Santa on his journey through the night, making sure he is not seen by children.
Stability: To walk in the snow without sinking or getting frostbite, reindeer have developed large, crescent-shaped hooves. These keep them stable, but they can also be used as shovels to dig for lichen under the snow.
The hoof pads shrink and harden during the winter, allowing reindeer to walk on the sharp edges of their hooves. In addition to reducing the area of the hoof exposed to cold ground, the hoof edges cut through ice and snow to prevent slipping. Obviously, this is a great adaptation to keep reindeer stable when they land on snowy rooftops.
Transport: Reindeer are the only domesticated species of deer and people have used them for movement since the Stone Age. People ride on their backs like horses and use small herds of them to drive sleighs, just like Santa Claus.
Reindeer migrate up to 5,000 km per year – farther than any other land mammal – and they regularly travel 55 km in a day. They are also surprisingly fast, reaching speeds of up to 80 km / h. This long-distance trip is ideal for helping Santa visit every child in just one night.
So reindeer can stay warm, see in the dark, stand on slippery surfaces, and find food in the harshest of environments – all invaluable skills to pulling off the biggest Christmas Eve night’s work. . Their domestication and long relationship with humans means that they are also well used to pulling sleds.
Of course, Santa’s reindeer can fly too. However, they cannot thank evolution for it, unlike all of these other adaptations. As we all know, their ability to fly comes from a dusting of magical Christmas dust.
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Posted on: Monday, December 13, 2021, 7:00 a.m. IST