Rudolph the Red-Nosed Reindeer is famous for pulling Santa’s sleigh, but researchers from the US and UK say its reindeer’s vision that really sets them apart.
Key points:
- Reindeer can see light in the ultraviolet spectrum
- Their vision may have evolved to protect them from predators and help find food
- Scientists say the mechanism that protects reindeer eyes from UV may have benefits for humans
Finding food in a cold, barren landscape is challenging and reindeer eyes may have evolved to allow them to easily spot their preferred food, according to Dartmouth anthropology professor Nathaniel Dominy, who co-authored a recent study in the journal i-Perception.
“They’ve been sort of obscure and unheralded in the annals of visual neuroscience, but they’re having their moment because they have a really fascinating visual system,” Professor Dominy said.
The mirror-like tissue in reindeer eyes changes colour from a greenish gold in the summer to vivid blue in the winter, a process that is believed to amplify the low light of polar winter.
But scientists have been working to understand why reindeer can see light in the ultraviolet spectrum.
“Most animals that are active under daylight conditions want to avoid UV light. UV light is damaging [and] snow reflects UV light, which is a problem, which is why humans get snow blindness,” he said.
Meanwhile, some scientists believe reindeer vision evolved to protect the animals from predators, allowing them to spot white wolves against a snowy landscape.
The new study points to another possibility: food.
Reindeer subsist largely on high-coloured reindeer moss, which isn’t actually a moss but rather a type of lichen that grows in crunchy, carpet-like patches across northern latitudes.
“I love every piece of work dealing with colours and vision, every time I read other people’s works, there is something that sparks new ideas,” Professor Dominy said.
“With the reindeer, I want to pay more attention to this part of the spectrum.”
He said while there was no immediate biomedical benefit to the research, it was useful in furthering scientific understanding of how animals dealt with difficult environments and noted it could benefit humans.
While much research has focused on lichens and their antioxidant properties, the ability of reindeer to allow UV light suggests there is a mechanism that protects them from damage.
“Reindeer eyes are full of vitamin C, and vitamin C is just terrific for repairing damaged cells,” he said.
When it comes to Christmas traditions, Professor Dominy recommended children save the milk and cookies for Santa.
“Orange juice or carrots, these would be perfect treats for reindeer on Christmas Eve,” he said.