Dec 13th 2021

Five ways reindeer are perfectly evolved for pulling Santa’s sleigh

by Louise Gentle

 

Senior Lecturer in Wildlife Conservation, Nottingham Trent University

 

We all know that Father Christmas would struggle to deliver presents to everyone around the world without the help of his magical reindeer. But why were they chosen to pull the sleigh rather than any other animal?

It turns out that the biology of reindeer makes them ideal for the job. Here are five reasons why.

Warmth

Reindeer live in the Arctic, where temperatures on long winter nights often plummet below -30°C. Unlike most mammals, which only have one layer of fur, reindeer have two: a dense underfur beneath a blanket of hollow guard hairs. Reindeer can have up to 2,000 hairs packed into a single square centimetre, making it ten times as dense as human hair. This double layer traps air and creates a cover of insulation that keeps reindeer from losing heat, and stops snow from reaching and cooling the skin. This enables reindeer to keep warm, whether living with Santa at the North Pole or travelling around the world on Christmas Eve.

In addition, when blood reaches our extremities, like our fingers and toes, it cools and our hearts must pump at a faster rate to warm the blood up again. This requires a lot of energy which we get from food, something that is often lacking in Arctic landscapes – well, unless you count feasting on candy canes and sugar plums with the elves.

But reindeer possess something called a counter-current heat exchange which essentially allows them to recycle heat so that the heart doesn’t need 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 the cold venous blood. A lot of this heat exchange happens in the specialised nasal bones of the reindeer, where plenty 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.

Fitness

Reindeer lichen – an organism that is formed from a symbiotic relationship between algae and fungi – is the main thing reindeer eat during the winter. Lichens are the crusty looking things that you often see living on tree trunks and rocks.

Lichens are plentiful in the Arctic – an ideal food source that reindeer can find wherever they go. This means reindeer don’t need to store body fat and unlike many other animals, they can find enough food to power their epic sleigh journey with Santa – helped along by the carrots people leave out, of course.

Reindeer are actually the only mammals capable of digesting lichen, thanks to specialised bacteria in their gut.

Sight

The Arctic has very little daylight during the winter, so reindeer have evolved to see as much as possible in the dark. Reindeer eyes change colour from gold to blue in the winter, letting in more of the small amount of light available and improving their vision.

Reindeer can even see in the ultraviolet. Although this amazing sense is common in birds and insects, reindeer are some of the only mammals to have evolved this ability. This means that objects that would blend into the background when seen through human eyes are much more visible to reindeer.

As reindeer can essentially see in the dark, it makes them perfect for guiding Santa on his journey through the night, ensuring he is not seen by children.

Steadiness

To walk in snow without sinking or getting frostbite, reindeer have evolved wide, crescent-shaped hooves. These keep them stable, but they can also be used as shovels to dig down to find lichen under the snow.

The hoof pads shrink and harden over winter, allowing the reindeer to walk on the sharp edges of their hooves. As well as reducing the area of the hoof exposed to the cold ground, the hoof rims cut into the ice and snow to prevent slipping. Obviously, this is a great adaptation to keep reindeer steady when landing on snowy rooftops.

Transport

Reindeer are the only domesticated species of deer, and people have been using them to get around since the stone age. People ride on their backs like horses, and use small herds of them to drive sleds, just like Santa.

Reindeer migrate up to 5,000km a year – further than any other land mammal – and they regularly cover 55km in a day. They are surprisingly fast too, reaching speeds of up to 80km per hour. This long distance travel is ideal to help Father Christmas visit every child in just one night.

So, reindeer can stay warm, see in the dark, stay upright on slippery surfaces and find nutrition in the harshest of environments – all invaluable skills for pulling off the biggest night’s work on Christmas Eve. Their domestication and long relationship with humans means they are also well accustomed to pulling sleighs.

Of course, Santa’s reindeer can also fly. They can’t thank evolution for that, though, unlike all these other adaptations. As we all know, their ability to fly comes from a sprinkling of magical Christmas dust.'

 

Louise Gentle, Senior Lecturer in Wildlife Conservation, Nottingham Trent University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Browse articles by author

More Essays

Jan 18th 2023
EXTRACT: "In 2018, former US president Bill Clinton coauthored a novel with James Patterson, the world’s bestselling author. The President is Missing is a typical “Patterson”: a page-turner of a thriller, easy to read, with short chapters and large font. Patterson is accustomed to collaborative writing ..... He is as much a producer as he is a writer, using a string of junior collaborators to run his factory of novels. Patterson outlines the plot, the coauthors write the story, Patterson offers feedback. While he doesn’t seem to do much writing himself, it is a system that has made Patterson a rich man."
Jan 14th 2023
EXTRACT: "With hindsight, 2022 will be seen as the year when artificial intelligence gained street credibility. The release of ChatGPT by the San Francisco-based research laboratory OpenAI garnered great attention and raised even greater questions.  In just its first week, ChatGPT attracted more than a million users and was used to write computer programs, compose music, play games, and take the bar exam. Students discovered that it could write serviceable essays worthy of a B grade – as did teachers, albeit more slowly and to their considerable dismay."
Jan 14th 2023
EXTRACT: "The thought of her, as always, gave me a jolt of hope, and a burst of energy. And a stab of sorrow."
Jan 14th 2023
EXTRACT: ".....if academic discourse and campus debate are shut down every time a person feels offended, how can universities possibly examine controversial topics? Without intellectual freedom – one of the great achievements of American civilization – they can’t."
Jan 5th 2023
EXTRACTS: "London's Tate Britain and Paris' Petit Palais have collaborated to produce a wonderful retrospective exhibition of the art of Walter Sickert (1860-1942).  The show is both beautiful and fascinating. ----- Virginia Woolf loved Sickert's art, and it is not difficult to see why, because his painting, like her writing, was always about intimate views of incidents, or casual portraits in which individual sitters momentarily revealed their personalities.  ------ Sickert's art never gained the status of that of Whistler or Degas, perhaps because it was too derivative of those masters.  But he was an important link between those great experimental painters and the art of Lucian Freud, Francis Bacon, Frank Auerbach, ...."
Dec 5th 2022
EXTRACT: "One of the great paradoxes of human endeavour is why so much time and effort is spent on creating things and indulging in behaviour with no obvious survival value – behaviour otherwise known as art. Attempting to shed light on this issue is problematic because first we must define precisely what art is. We can start by looking at how art, or the arts, were practised by early humans during the Upper Palaeolithic period, 40,000 to 12,000 years ago, and immediately thereafter."
Dec 3rd 2022
EXTRACTS: "As a portrait artist, I am an amateur at this compared to the technology gurus and psychologists who study facial recognition seriously. Their aplications range from law enforcement to immigration control to ethnic groupings to the search through a crowd to find someone we know. ---- In my amateur artistic way, I prefer to count on intuition to find facial clues to a subject’s personality before sitting down at the drawing board. I never use the latest software to grapple with this dizzying variety.
Dec 1st 2022
EXTRACT: "In the exhibition catalog Lisane Basquiat writes: 'What is important for everyone to understand… is that he was a son, and a brother, and a grandson, and a nephew, and a cousin, and a friend. He was all of that in addition to being a groundbreaking artist.' "
Nov 24th 2022
"The art of kintsugi is inextricably linked to the Japanese philosophy of wabi-sabi: a worldview centred on the acceptance of transience, imperfection and the beauty found in simplicity.....nothing stays the same forever." --- "The philosophy of kintsugi, as an approach to life, can help encourage us when we face failure. We can try to pick up the pieces, and if we manage to do that we can put them back together. The result might not seem beautiful straight away but as wabi-sabi teaches, as time passes, we may be able to appreciate the beauty of those imperfections."
Oct 25th 2022
EXTRACT: "The prime minister of India, Narendra Modi, was quick to congratulate Sunak, referring to him as “the ‘living bridge’ of UK Indians”. In the difficult waters of British and indeed international politics, all eyes will be watching to see how well the bridge stands."
Oct 5th 2022
EXTRACTS: "In the Guardian, Peter Bradshaw eulogized Jean-Luc Godard as 'a genius who tore up the rule book without troubling to read it.' This is a fundamental misunderstanding." ----- " As had been true for Picasso - and Eliot, Joyce, Dylan, and Lennon - it was Godard's mastery of the rules of his discipline that made his violation of those rules so exciting to young artists, and his work so influential.  But perhaps these innovators' mastery of the rules can only be seen by those who themselves understand the rules."
Sep 29th 2022
EXTRACTS: "For many of us, some personality traits stay the same throughout our lives while others change only gradually. However, evidence shows that significant events in our personal lives which induce severe stress or trauma can be associated with more rapid changes in our personalities." ----- "Over time, our personalities usually change in a way that helps us adapt to ageing and cope more effectively with life events." ----- " ....participants in this study recorded changes in the opposite direction to the usual trajectory of personality change." --- "....you might like to take the time to reflect on your experiences over the past few years, and how these personality changes may have affected you."
Sep 21st 2022
EXTRACTS: "It might seem like an obscure footnote among the history-making events of 2022, but the year of Queen Elizabeth II’s death coincides with the 300th anniversary of Adam Smith’s birth." ----- "As a committed Stoic, Smith had little patience for greed. The whole point of Roman Stoic philosophy was to use personal moral discipline to support the rule of law and constitutions, and to make society a better place." ----- "When we read Smith, we are better served to think of the example of Elizabeth II than of those driven by personal greed. It might sound archaic, but, as Britons’ response to her death suggests, these values still appeal to a great many people today."
Sep 14th 2022
EXTRACT: "On the day of Queen Elizabeth II’s death, the former Prince of Wales was proclaimed King Charles III. Although it’s been known for decades that Charles would succeed his mother, there were rumours that he might, once king, choose the name George due to the contentious legacies of Kings Charles I and Charles II."
Aug 25th 2022
EXTRACT: "An over-emphasis on looking for the chemical equation of depression may have distracted us from its social causes and solutions. We suggest that looking for depression in the brain may be similar to opening up the back of our computer when a piece of software crashes: we are making a category error and mistaking problems of the mind for problems in the brain. It would be wise to observe caution with drugs whose effectiveness is not certain, whose mode of action is unknown, and which have many side-effects, especially for use in the long term."
Jul 29th 2022
EXTRACTS: "China uses incarcerated prisoners of conscience as an organ donor pool to provide compatible transplants for patients. These prisoners or “donors” are executed and their organs harvested against their will, and used in a prolific and profitable transplant industry."
Jul 29th 2022
EXTRACT: "In the first episode of season three of The Kominsky Method (2021), there is a funeral service for Michael Douglas’ character’s lifelong friend Norman Newlander (played by Alan Arkin). By far the most inconsolable mourner to give a eulogy is Newlander’s personal assistant of 22 years who, amid a hyperbolical outpouring of grief, literally cannot bring herself to let go of the casket. It is a humorous scene, to be sure, but there is something else going on here that is characteristic of employer-employee relations in this era of neoliberal capitalism. “Making him happy made me happy,” she exclaims, “his welfare was my first thought in the morning, and my last thought before I went to sleep.” That isn’t sweet – it is pathological. ----- Employee happiness is becoming increasingly conditional on, or even equated with, the boss’ happiness. As Frédéric Lordon observes in his book, Willing Slaves of Capital (2014), “employees used to surrender to the master desire with a heavy heart…they had other things on their minds…ideally the present-day enterprise wants subjects who strive of their own accord according to its norms.” In a word, the employee is increasingly expected to internalize and identify with the desire of the master."
Jul 20th 2022
EXTRACT: "For three decades, people have been deluged with information suggesting that depression is caused by a “chemical imbalance” in the brain – namely an imbalance of a brain chemical called serotonin. However, our latest research review shows that the evidence does not support it."
Jul 13th 2022
"But is he “deluded”? " ---- "....we sometimes end up with deluded leaders because we ourselves can be somewhat delusional when we vote." ---- "David Collinson, a professor of leadership and organization at Lancaster University, associates this predicament with excessive positive thinking, or what he calls “Prozac leadership,” in reference to the famous antidepressant that promises to cheer people up without actually fixing what is wrong in their lives. “ ---- "In politics, Prozac leaders come to power by selling the electorate on wildly overoptimistic views of the future. When the public buys into a Prozac leader’s narrative, it is they who are already verging on the delusional." ----- "Another potential example is Vladimir Putin, who has conjured a kind of nostalgic dream world for his followers and the wider Russian public."
Jun 25th 2022
EXTRACT: "Many veterans, refugees and other people who have experienced trauma and have mental health issues spend little time thinking about the future. Instead, they are narrowly focused on the negative past. However, people who have experienced trauma and developed a healthy future perspective report being better at coping with life, having fewer negative thoughts about the past, and getting better sleep compared with those who have a negative future perspective. So, instead of dwelling on the past, people who have suffered trauma should be encouraged to think about the future and set goals that help them develop hope for a good life."