2023-12-23 08:32:02
CONCORD, N.H. (AP) — Rudolph the red-nosed reindeer may find millions of carrots prepared for him on Christmas Eve, but what regarding the rest of the year?
Finding food in a cold, desolate landscape is a challenge, but researchers from Dartmouth College in New Hampshire and the University of St. Andrews in Scotland indicated that reindeer eyes may have evolved to help them easily locate their preferred food. .
It’s new evidence that while reindeer are famous for pulling Santa’s sleigh, what really characterizes them is their vision, said Nathaniel Dominy, a Darthmouth anthropology professor and co-author of a recent study published in the journal i- Perception.
“They have been a bit in the shadows and underrecognized in the annals of visual neuroscience, but they are having their moment because they have a fascinating visual system,” he said in an interview.
Scientists have known for years that the mirror-like tissue in reindeer eyes changes color, from a greenish gold in summer to a vivid blue in winter, a process believed to amplify the poor light of the polar winter. But they weren’t sure how to interpret another curious fact: unlike other mammals, reindeer can see in the ultraviolet spectrum.
“Most animals that are active in daylight conditions want to avoid ultraviolet light. Ultraviolet light is harmful,” Dominy explained. “Snow reflects ultraviolet light, which is a problem, which is why snow causes blindness in humans.”
Some scientists believe that reindeer vision evolved to protect the animals from predators, for example allowing them to spot white wolves in a snowy landscape. The new study points to another possibility: food.
Reindeer subsist largely on the so-called reindeer lichen, which forms crisp, light-colored mats on the ground in northern latitudes.
Researchers who traveled to the Cairngorms mountains in the Scottish Highlands, where there are more than 1,500 species of lichen, as well as the UK’s only herd of reindeer. They discovered that reindeer lichen absorbs ultraviolet light, so white lichen that is difficult for humans to see stands out as dark shadows to animals.
“If you’re a reindeer, you can see it and you have an advantage because then you’re not wandering around the countryside. You can walk in a straight line and get that food, and you save energy in the process,” Dominy said. “These animals are desperate for food, and if they can find enough lichen, then they have an advantage.”
Juan José Negro, from the Spanish Higher Council for Scientific Research, specializes in ecology and evolutionary and conservation biology. Although he primarily studies birds of prey, he found the new reindeer research intriguing.
“I love all the work on colors and vision,” he said. “Every time I read other people’s work, there is something that inspires new ideas (…) and in the case of reindeer, this leads me to pay more attention to this part of the spectrum.”
Although he didn’t see immediate biomedical applications for the report, he said, the work is useful for increasing understanding of how animals cope with difficult environments.
Dominy agreed with that argument, although he said it also has human implications. There is a lot of pharmacological research on lichens because they have antioxidant properties. The fact that reindeer eyes can perceive ultraviolet light suggests there may be some mechanism that protects them from harm, he said.
“Reindeer eyes are full of ascorbic acid, or vitamin C, and vitamin C is fantastic for repairing damaged cells,” he said.
With that in mind, Dominy is updating the recommendation he made following writing a 2015 report that studied why a red nose on a reindeer would be ideal for guiding Santa’s sleigh.
Then he recommended that the children leave Rodolfo cookies and other high-calorie foods to compensate for the body heat he loses through his nose. Now, he pointed out, we need to focus on his eyes and leave the milk and cookies for Santa Claus.
“The best thing you can give them to protect the health of their eyes would be something rich in vitamin C,” he said. “Orange juice, carrots, these would be the best treats for reindeer on Christmas Eve.”
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