We are independent & ad-supported. We may earn a commission for purchases made through our links.
Advertiser Disclosure
Our website is an independent, advertising-supported platform. We provide our content free of charge to our readers, and to keep it that way, we rely on revenue generated through advertisements and affiliate partnerships. This means that when you click on certain links on our site and make a purchase, we may earn a commission. Learn more.
How We Make Money
We sustain our operations through affiliate commissions and advertising. If you click on an affiliate link and make a purchase, we may receive a commission from the merchant at no additional cost to you. We also display advertisements on our website, which help generate revenue to support our work and keep our content free for readers. Our editorial team operates independently of our advertising and affiliate partnerships to ensure that our content remains unbiased and focused on providing you with the best information and recommendations based on thorough research and honest evaluations. To remain transparent, we’ve provided a list of our current affiliate partners here.

What Color Eyes Do Arctic Reindeer Have?

Depending on when you see them, the eyes of an arctic reindeer will change in color. In the summer, they're almost golden. In the winter, they seem deep blue. This is not due to a change in their mood or even a reaction to the temperature, but rather because of a change in the amount of overall light in the environment.

What you're really seeing is light reflected off a thin layer of tissue at the back of the arctic reindeer's eyes, like a mirror. Called the

tapetum lucidum

, this tissue helps them see at night. In the Arctic, there is a significant difference in the amount of available seasonal light. While there is lots of light during the long days of summer, the Norwegian winter means darkness for months, so a reindeer's eyes are constantly dilated. Dilation increases intraocular pressure (the fluid pressure within the eye) and that pressure changes the density of collagen fibers in the tapetum lucidum. In turn, the density of these fibers affects the wavelength of the light that the tapetum lucidum reflects back, from one end of the color spectrum to the other.

More facts about arctic reindeer:

  • Researchers think these changes in eye color are unique to arctic reindeer. Other critters whose eyes have a tapetum lucidum, such as horses and house cats, don't exhibit this seasonal shift.
  • Arctic reindeer can see in low light conditions, and although that world is not in focus, it is usually sufficient for them to recognize a predator on the prowl.
  • Researchers also found a herd with green eyes living near a Norwegian university, where community lighting keeps their habitat dimly lit.
Discussion Comments
WiseGeek, in your inbox

Our latest articles, guides, and more, delivered daily.

WiseGeek, in your inbox

Our latest articles, guides, and more, delivered daily.