The human eye can identify roughly 10 million colors, but animals have us beat when it comes to adapting to the environment. According to new research, the eye colors of Arctic reindeer change with the seasons.
During the summer months when the sun never sets in the frozen tundra, their eyes appear gold, with retinas allowing in as much light as possible. When it’s dark for 24 hours a day in the winter, their eyes turn deep blue, which reflects very little light out of the eye.
According to the Biotechnology and Biological Sciences Research Council, this helps them see better to detect predators and track down food. Dr. Glen Jeffery, chief researcher from the University College London, says it’s the first time scientists have ever seen eyes change color in mammals.