1. Is a reindeer like a caribou?
Yes; in fact, caribou is the North American name for reindeer. As a North American, I will call the animal a caribou in this article. At least until the end.
2. They click when they walk.
There is a tendon in the front legs of caribou that snaps when they walk, making a click that can be heard from 30 feet away. Scientists believe this is a trait developed by the male to signal to other males just how big he is, and in fact, a study by a couple of Scandinavian fellows shows that the sound does correlate to the size of the animal. What I find curious about this, though, is that the study did not mention if the sound is present in female caribou or whether it matters to the ladies, who are not inclined to fight.
3. Heat exchange.
Did you ever wonder about the blood in a caribou’s legs getting cold? (Are you wondering about it now?) It turns out that arctic animals have veins and arteries that are closely knitted near their extremities so that the cold blood in the veins is warmed by being close to the arteries while the warm blood in the arteries is cooled being close to the veins. The blood going into the legs is already colder than in the rest of the body. This allows the core body temperature to remain 30 degrees Celsius higher than the blood in the legs. Neat, eh?
4. Floating caribou.
Like many animals, the caribou has two layers to its coat: a woolly undercoat and a long overcoat made of hollow hairs. The strange thing about this is that when they swim—which they do—they float unusually high. The hollow hair acts like a lifejacket!
5. Hoof shovels.
Caribou have two large toes per foot, shaped like crescents. In the summer, the footpads are thick and spongey, to offer traction. In the winter, the footpads tighten and shrink, exposing the hoofs. They are good for digging through snow to get to lichen underneath.
6. Wait, lichen?
That’s right, caribou can eat lichen. They are one of the only animals that can metabolize the stuff. In fact, when offered a wide variety of foods, caribou will choose lichens first although they contain almost no protein. Scientists believe this is because lichens require very little water to metabolize, meaning caribou don’t need to eat as much snow, which would lower the body temperature.
7. They eat snow?
They actually prefer snow to fresh water in winter. It seems to be for the same reason they prefer lichen: snow contains almost no minerals, which means caribou don’t need to urinate as often, which means they don’t get rid of the water they drink as snow so fast.
8. Breathing cold air.
To warm the air they inhale, caribou nostrils look like rolled up newspapers inside. The extra surface area warms up the air breathed in and also traps the heat and moisture breathed out; the moisture is added to the dry air they breathe in.
Caribou females grow antlers as well as males, the only species of deer to typically do so. The antlers are important for defence against non-caribou species and they’re used by males to do battle for females during the rut. After the rut, males shed their antlers, but pregnant females will keep them through calving, meaning they are able to defend the feeding areas they have dug out of the snow.
10. Female reindeer.
A couple of years ago there was a meme going around that Santa’s reindeer must be female because the males all lose their antlers after the rut in the fall; so do non-pregnant females. It turns out that Dasher, Dancer, Prancer et al were not only female, they were pregnant!
— Shauna Dobbie
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