The Animal That Changes Colour Of Its Eyes
By: EjazUlHaqBhat
Image: Unsplash
The eyes of Arctic reindeer changes colour from golden in the summer to deep blue in the winter
Image: Unsplash
The tapetum lucidum (TL), a light-reflecting layer of tissue behind the retina, reflects most light back through the retina, giving the eye a golden colour
Image: Unsplash
The TL changes to a deep blue, reflecting less light out of the eye. This change helps reindeer see better in the winter's darkness and spot predators in low light
Image: Unsplash
The colour change is caused by the TL adjusting to the increased fluid pressure in the eye, which occurs when the pupils are constantly dilated in the winter
Image: Unsplash
This adjustment makes the eyes between 100 to 1,000 times more light sensitive
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The colour change helps reindeer to adapt to the extreme lighting changes in their environment
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In the Arctic, there are long hours of bright light in the summer and almost total darkness in the winter
Image: Unsplash
Even though it's dark in the winter, reindeer still have to eat and protect themselves from predators
Image: Unsplash
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