Have you ever wondered how reindeer survive the harsh conditions of their home? It turns out that they are really well adapted to the environment they live in - check out how...
- Reindeer Snouts Heat Each Breath (and Glow Under Thermal Imaging)
- Reindeer Eyes Turn Blue in Winter to Deal With the Darkness
- Ultra-Dense Fur Lets Reindeer Survive -72°C (-97°F) Temperatures
- Reindeer Have Clicking Legs and All-Terrain Hooves
- Reindeer Antlers are Bone Spikes Grown in a Velvet Glove
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| Cold conditions require clever adaptations... (Natalia_Kollegova) |
Reindeer Snouts Heat Each Breath (and Glow Under Thermal Imaging)
You've probably heard of Rudolf the Red-Nosed Reindeer? Well, while the snouts of his real-world kin are not red, they do blaze like fire when viewed with thermal imaging!
The snout of a reindeer has adapted to help deal with this problem, warming air before it can reach the lungs. The internal structure of a reindeer's nose resembles the whorls of a seashell, which gives it an enormous surface area. Each bit of flesh is packed with blood vessels and acts like an organic radiator, with the hot blood warming each breath as it comes in!
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| Reindeer eyes take on a blue tint in the winter... (Arseny Togulev) |
Reindeer Eyes Turn Blue in Winter to Deal With the Darkness
Many animals can change the color of their coat with the season—but few can change the color of their eyes. Reindeer eyes change from gold in summer to blue in winter... which actually gives them better vision in the dimming sun.Like many animals, the eye of a reindeer has a tapetum lucidum. This is a bit like a biological mirror behind the retina - and it allows light that enters the eye but misses the retina a second chance to be "seen" as it gets reflected! If you see a cat's eyes shining in darkness, you're witnessing the tapetum lucidum in action.
Now those golden eyes are fine for the bright Arctic summer, but the winter months plunge the region into darkness. The reindeer's tapetum lucidum changes to reflect blue rather than gold light (changing how they look) and their eye's become around a thousand times more sensitive to light as a result.
Reindeer also have a trick for dealing with the long days and nights of the Arctic. Researchers have found that reindeer melatonin levels don't change throughout the course of the day, which means that they lack an internal clock.
Perhaps that doesn't sound like an advantage... but have you ever been jet-lagged? Reindeer simply don't have that problem. If you're wondering how they know when to sleep, the answer is simple - they take a nap after eating!
Ultra-Dense Fur Lets Reindeer Survive -72°C (-97°F) Temperatures
Given where they live, it shouldn't be surprising that reindeer have a thick and heavily insulated coat of fur. This coat can get extremely dense - in winter, there can be as many as 2,000 hairs per square inch.
The fur is made up of specialized hairs, with a thick woolly undercoat of ground hair (to trap heat and keep the animal warm) covered by an outer layer of long, hollow guard hairs that protect against the weather.
The reindeer can shed their winter coat in the warmer seasons, but until then the coat offers almost complete protection against temperatures of -30°C (-22°F) and can allow the animal to survive in as low as -72°C (-97°F.)
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| Reindeer antlers grow beneath a coat of velvety fur... (Natalia_Kollegova) |
Reindeer Have Clicking Legs and All-Terrain Hooves
It's not only the fur and eyes of reindeer that change with the seasons - their hooves adapt as well. In the colder months of winter, the pillow (fleshy pad) of each hoof contracts. This exposes the hard rim of the hoof, allowing it to dig into snow and ice for a better grip. In warmer months the pillow expands again, providing a greater surface area and thus more friction on damp ground.
Reindeer also click as they walk. The click seems to come from a tendon slipping over a bone in their back legs as they take a step. It's quietest in calves, but loudest in the large males.
It's thought that this is an energy efficient way to keep a herd together. During the limited visibility of harsh weather, the loud clicks could act like a beacon for the other reindeer to muster around. You might wonder why they don't just bellow - the answer is that it would cost the reindeer precious body heat to open their mouths and roar into the storm, while the passive clicks of a moving reindeer cost them nothing.
If you're wondering why staying together matters so much for reindeer, it's how they defend themselves against predators. Strength in numbers is their only answer to polar bears, wolf packs and even eagles that might fancy their chances against a calf!
Reindeer Antlers are Bone Spikes Grown in a Velvet Glove
If you were to form a mental picture of a reindeer, you'd probably include a prominent set of antlers. Both male and female reindeer grow these antlers, which are shed and regrown each year (starting in February and growing around half an inch each day.)
During this event, male reindeer lock antlers and try to push each other away - winners get access to mates, whilst losers get to leave with their life. Males lose their antlers at the end of the rut, but females keep them longer - usually until they've calved. It's thought that large antlers might be a form of dominance display amongst the females, allowing them to claim better feeding grounds for themselves.
Humans throughout history have made use of the antlers as naturally occurring tools, but in 2014 the Finnish attempted to use them for reindeer road safety - they trialed spraying their antlers with reflective paint to make them show up in headlights and prevent night-time driver collisions!
Thanks for reading - for more chilly facts, try...