CONCORD, NH (AP) Rudolph the red-nosed reindeer may have millions of carrots prepared for him on Christmas Eve, but what about the rest of the year?
Finding food in a cold, barren landscape is challenging, but researchers from Dartmouth College in New Hampshire and the University of St. Andrews in Scotland reported that the reindeer’s eyes may have evolved so that they could easily find the food they wanted.
It’s more evidence that while reindeer are famous for pulling Santa’s sleigh, it’s their vision that really sets them apart, said Nathaniel Dominy, a professor of anthropology at Dartmouth and co-author of a new study that published in the journal i-Perception.
They have become obscure and unknown in the annals of visual neuroscience, but they have their chance because they have a fascinating visual system, he said in an interview.
Scientists have known for years that the glass-like tissue in reindeer eyes changes color from green-gold in summer to bright blue in winter, a process believed to be magnifies the little light of the polar winter. But they weren’t sure what to make of another amazing fact: Unlike other mammals, reindeer can see light in the ultraviolet spectrum.
Most animals that are active under sunlight want to avoid UV light. UV light is harmful, said Dominy. Snow reflects UV light, which is a problem, so people are blinded by snow.
Some scientists believe that reindeer vision evolved to protect the animals from predators, allowing them to spot white wolves against a snowy landscape, for example. A new study points to another possibility: diet.
Reindeer usually live on light-colored reindeer moss, which is not actually moss but a type of lichen that grows in crinch, carpet-like patches in northern latitudes.
The researchers traveled to the Cairngorms mountains in the Scottish Highlands, which have more than 1,500 lichen species as well as Britain’s only reindeer herd. They found that the reindeer moss absorbs UV light, which means that the white lichen that people have trouble seeing against the snow can be seen as black patches to the animals.
If you’re a reindeer, you can see it and you have an advantage because you don’t roam the landscape. You can walk in a straight line and get to that meal, and you save energy in the process, Dominy says. These animals are desperate for food, and if they find enough lichen, then they have an advantage.
Juan Jose Negro specializes in evolutionary ecology and conservation biology at the Spanish Council for Scientific Research. While his focus is primarily on birds of prey, he finds the new reindeer research fascinating.
I love every piece of work that deals with colors and perspective, she said. Every time I read other people’s work, something sparks new ideas. And in the case of reindeer, it leads me to want to pay more attention to this part of the spectrum.
While he sees no immediate biomedical benefit to the research, such work is useful in furthering understanding of how animals cope in difficult environments, he said.
Dominy echoed that point, but said it also had human implications. There is a lot of pharmacological research about lichens because they have antioxidant properties. The fact that the reindeer’s eyes allow UV light suggests there is some mechanism in place to protect them from damage, he said.
Reindeer eyes are full of ascorbic acid, or vitamin C, and vitamin C is great for repairing damaged cells, he said.
With that in mind, Dominy updated the advice he offered after writing a 2015 paper exploring why a reindeer’s red nose is good for guiding Santas sleigh.
In the past, he recommended children give up Rudolph cookies and other high-calorie foods to regain the body heat lost through his nose. Now, he said, roll his eyes and save the milk and cookies for Santa.
The best thing to give them to protect their eye health is something rich in vitamin C, he said. Orange juice, carrots, this will be the perfect food for the reindeer on Christmas Eve.
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