(WYTV) – The following facts are all about reindeer.

People began domesticating reindeer about 3,000 years ago in Eastern Russia and the Scandinavian countries and, of course, once a year, they pull Santa’s sleigh around the world to deliver presents.

In the Arctic wild, reindeer live on the tundra plain between the timberline and the polar ice cap.
They eat the leaves of willow and birch trees and grasses; they are kind of picky eaters.

Reindeer can see ultraviolet light. That’s unusual for mammals, but some birds, bees and a few fish can distinguish ultraviolet light, which is outside our spectrum.

Reindeer use their special eyesight to spot lichen, a fungus that’s a major food source in the Arctic.
Reindeer, the ones living in harsher climates, really do have red noses and for good reason. The noses are densely packed with blood vessels that help regulate their body temperatures.

Reindeer eyes can change color from gold to blue, and back again.

During Arctic summers, when daylight is continuous, reindeers’ eyes turn golden because most of the light is reflected back from their retinas.

In the winter, with continual darkness, tissue behind the retina actually becomes less reflective.
This causes their eyes to take on a blue color.

Santa’s reindeer are most likely female. Most male reindeer shed their antlers in early December at the end of the mating season, while female reindeer keep their antlers throughout the winter.

And while male reindeer thin down during mating season, female reindeer go into winter with 50% body fat to keep them nice and toasty during low temperatures, like all that wind chill while they’re up there pulling a sleigh.