We all grew up hearing the story of “Rudolph the Red-nosed Reindeer,” and how he saved Christmas one foggy night by guiding Santa’s sleigh with the help of his red nose.
But did you know there is scientific evidence that backs up this story? In a paper published in Frontiers For Young Minds, Nathaniel J. Dominy, a Professor of Anthropology at Dartmouth, explored the benefits of having a shiny red nose, particularly on a cold, foggy Christmas night, reports Newser.
His notebook included sketches by Denver L. Gillen. This page illustrates the red glow or luminescence of Rudolph’s red nose under dark and drear atmospheric conditions (reproduced with permission of the Rauner Special Collections Library, Dartmouth College).
The reindeer’s ability to see ultraviolet light
Dominy says there’s an optical explanation behind the reindeer’s red nose. The scholar cites a number of studies on the unique eyes and vision of Arctic reindeer and points out that Arctic reindeer (Rangifer tarandus tarandus) can see ultraviolet light, something we humans cannot do.
This ability to see ultraviolet light (UV vision) is really handy in the far-northern reaches of the Arctic, especially in mid-winter when the sun hangs low on the horizon. Having UV vision is perfect for reindeer because it helps them to see predators, like the Arctic fox, and makes it easier to find lichen, their favorite food. This is because snow reflects UV light and makes it look bright.
A reindeer’s eyes have reflective tissues called tapetum lucidum. This tissue gives the eyes a deep golden-brown color during the summer months and a deep blue color during the winter months. The tapetum lucidum, which causes the eyes to shine at night, helps nocturnal animals to see blue light in the dark. Just so you know, this is why a wild animal’s eyes light up at night when a car’s headlights shine on them.
But there is one big problem with this unusual ability to see blue light. Fogs during late December extinguish blue light a lot easier than red light, and this makes it very difficult for Santa’s reindeer to see blue easily, let alone try to fly in those conditions.
Rudolph’s red nose comes into play
Rather than go into a long drawn out explanation into the why’s and how’s of Mie scattering, “a process named after Gustav Mie, a German professor of physics, who explained what happens when round or spherical particles of certain sizes cause light to scatter,” according to the study, this scattering of light can make it difficult to see through most types of fogs.
According to one version of the story of Rudolph, the Red-nosed Reindeer, he hid behind a holly bush so that “his bright red nose blended in with the bright red berries.” Because Rudolph’s nose is so close to the color of holly berries, Dominy was able to estimate the color of the light emitted from Rudolph’s nose by measuring the color of the holly berries.
Dominy says that according to his calculations, Rudolph’s nose probably has the maximum amount of redness needed to be seen by other animals during a foggy night, making it a very good fog lamp. Dominy does warn children that having such a red nose is a bit of a problem for Rudolph because reindeer noses that red tend to be very vascular, and body heat can be lost quickly.
To keep Rudolph from being at risk of developing hypothermia, Dominy says,”It is therefore imperative for children to provide high-calorie foods to help Rudolph replenish his energetic reserves on Christmas Eve.”
