Reindeer are famous for pulling Santa’s sleigh, but there is a distinctive feature that sets them apart from others. Finding food in cold, desolate landscapes is a challenge, but researchers from Dartmouth College in New Hampshire and the University of St Andrews in Scotland point out that reindeer eyes may have evolved to enable them to easily spot their favorite meal.
The Color Change of Mirror Eyes
Biologists have known for years that mirror-like tissues in reindeer eyes change color from green-gold in summer to bright blue in winter, and this process is believed to enhance low light in the polar winter. However, they were not sure about the true significance of this strange fact: unlike other mammals, reindeer can see light in the ultraviolet spectrum.
Vision and Food
Some scientists believe that reindeer vision evolved to protect the animals from predators, allowing them to see white wolves against snowy backgrounds, for example. The new study suggests another possibility: food. Reindeer rely heavily on light-colored reindeer lichen, which is not actually a lichen but a type of moss that grows in patchy groups across northern latitudes.
Absorbing Ultraviolet Light
The researchers traveled to the Cairngorms in the Scottish Highlands, which is home to over 1,500 species of moss and also the only herd of reindeer in Britain. They found that reindeer lichen absorbs ultraviolet light, meaning that the white lichen that is hard for humans to see against the snow stands out as dark patches for the animals.
Human Benefits
This study suggests that there is some mechanism protecting reindeer eyes from damage. Reindeer eyes are filled with ascorbic acid, or vitamin C, which helps repair damaged cells. Considering this, Dominy is updating the advice he gave after writing a scientific paper in 2015 exploring why a reindeer’s red nose is perfect for guiding Santa’s sleigh. Now, he says attention should be focused on their eyes and providing milk and cookies for Santa.
Source: https://apnews.com/article/how-reindeer-find-food-eyes-838c1854938e71e973363a651cda8fb0
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