To cope with the dark, gloomy winters and bright, sunny summers, their eyes change color. Their irises have a frosty blue color in the winter and a golden color in the summer. Each of these hues encourages a different kind of visual advantage, either enabling individuals to see through the shadows or to avoid squinting in the bright sunlight.

Normally, the eyes of reindeer are golden. Their pupils dilate for months on end throughout the long winter. All of this work wears out the reindeer’s eyes, which enlarge and put pressure on the tapetum.

A thousand times more light may be detected by the wintery blue than by the summery yellow. Contrarily, the latter shade functions as a pair of natural sunglasses in the summer by reflecting most of the light away from the animals’ eyes.

Also Read – What is a Baby Turkey Called?