The British University College of London’s Institute of Ophthalmology has led with their collegues of the Arctic University of Tromso in Norway a research on Arctic reindeers’ eyes. The below video indicates their eyes is changing colors with the season, shifting from gold in summer to deep blue in winter in order to adapt to extreme changes in light levels throughout the year.
Previous work had shown that Arctic reindeer eyes can also see ultraviolet, which is abundant in Arctic light but invisible to humans, and that they use this to find food and see predators.
This new study has been published in the Proceedings of the Royal Society on the 30th of October 2013 : “… Arctic reindeer experience extreme changes in environmental light from continuous summer daylight to continuous winter darkness. Here, we show that they may have a unique mechanism to cope with winter darkness by changing the wavelength reflection from their tapetum lucidum (TL)… read here their article >> ”