The evolution has helped animals to adapt to different seasons by changing something in their body, whether it be longer hair to keep warm, sleeping routine or color of the body. But who would ever think that reindeer have the ability to change their eye color?
This unusual fact was actually discovered very recently by researchers. Apparently, in the summer months, reindeer eyes are golden, while during the winter, they become a deep, rich blue. This comes as a result of the necessity of these animals to cope with three months of constant summer sunlight and three months of perpetual winter darkness.
The color change helps reindeer to see better in the continuous daylight of summer and continuous darkness of Arctic winters, by changing the sensitivity of the retina to light. (according to research conducted by scientists at the UCL Institute of Opthalmology and the University of Tromsø, Norway ).
Arctic reindeer, like many animals, have a layer of tissue in the eye called the tapetum lucidum(TL) which lies behind the retina and reflects light back through it to enhance night vision.
In the bright light of summer, the TL in Arctic reindeer is gold, similar to many other mammals, which reflects most light back directly through the retina. However, by winter it has changed to a deep blue which reflects less light out of the eye.
Other mammals do not possess this amazing ability and the reindeer case is the first time a color change of this kind has been shown.
This color change, except that it is very pretty, it gives the reindeer a special flexibility to cope better with the extreme differences between light levels in their habitat during the sunshine-filled days of the summer and the refective snow of the winter. One cannot help but wonder: How come that with all this advanced sighting ability, they still jump in front of cars?!
