Reindeer Eyes Turn Blue as Christmas Nears
The fictional Rudolph had a shiny nose to cope with winter darkness, but real-life reindeer possess some magic of their own. Part of the reindeer eye shifts from gold to winter blue, improving their ability to use light when the days become shorter, according to a new study.
The study, published in the latest Proceedings of the Royal Society B, helps to explain how Arctic reindeer continue to see in near darkness.
The part of the eye that changes color is the tapetum lucidum, commonly known as the ‘cat’s eye.’ It resides under an unpigmented part of the retina.
“In summer, it is golden with most light reflected back directly through the retina, whereas in winter it is deep blue with less light reflected out of the eye,” wrote Karl-Arne Stokkan, of the University of Tromso in Norway, and colleagues.
Stokka was able to study reindeer right at the university. Several were brought in from mountain region herders. They were maintained in large outdoor pens. The researchers studied their eyes during two weeks on either side of the summer and winter solstices.
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