Do reindeer's eyes really change color? If so, why, and how does this adaptation actually work in the wild? The eyes do change color, but that change takes place in the back of the eye, which can't be seen through photos such as these. The images in the post don't show this phenomenon. The seasonal eye color change in reindeer is unique among mammals, but plenty of other creatures display eye adaptations for different light environments.
For instance, cats and dogs have tapeta that boost night vision year-round, but they don't alter color. Reindeer are the only animals known to change eye color in the winter, but the effect isn't so outwardly obvious. Reindeer eyes change color during the winter, from golden to blue, something researchers say helps them to capture more light during the Arctic's dark winter months.
Why do reindeer's eyes change color with the seasons? In this video, Alex Dainis explains why reindeer eyes change color from orange. Reindeer change the color of a reflective layer in their eyes between summer and winter to deal with months. Scientific studies on reindeer ocular anatomy have consistently shown that the color of their eyes remains constant throughout the year.
The pigmentation of the iris, responsible for determining eye color, is not influenced by seasonal changes. Reindeer don't have red noses, but their eyes do turn green to blue in the winter. Scientists are finally figuring out why.
Why do reindeer's eyes change color with the seasons? In this video, Alex Dainis explains why reindeer eyes change color from orange-gold in the summer to blue in the winter. This change allows them to UV light in the winter time, which might seem counterintuitive because of their bright, snowy habitat. However, the reindeers' food source is a light colored lichen that absorbs UV.