Robert May, author of the tale of Rudolph the nasally colorful reindeer may have known a lot more science than we usually give him credit for. Seventy-six years after May invented Rudolph as a marketing gimmick for retailer Montgomery Ward, a paper has been published explaining the story in line with the latest discoveries about reindeer vision.
This addition to scientific knowledge comes from Dartmouth University's Professor Nathaniel Dominy and has been published on Frontiers for Young Minds, a website that describes itself as “science edited for kids, by kids”. Frontiers for Young Minds' papers are written by “distinguished scientists” and its editors are also working in scientific research. Papers are reviewed by a science mentor collaborating with someone aged 8-15, who provides feedback on the writing that the author must address.
Dominy ignores the now far more famous song, and goes back to the primary source, quoting May as referring to Rudolph's nose as “'dazzling' in daylight and 'glowing' at night.” Dominy suggests Rudolph's nose has remained unstudied because, “It is considered anomalous....As a general rule, scientists avoid studying anomalous traits. The fact that luminescent noses are so rare explains why the color and advantages/disadvantages of luminescent noses are practically unstudied.”
Dominy argues, “New findings about the color vision of reindeer could hold important clues about the value of a luminescent nose.” The discovery that Arctic reindeer (Rangifer tarandus tarandus) can see ultraviolet light is a recent one. Most animals that can see light with longer or shorter wavelengths than humans have specific receptors, but reindeer do not, which may have delayed discovery of their capacity.
Reindeer have lenses and cornea that let through UV light, and the blue light receptors in their retina also respond to light of shorter wavelengths than those of other mammals, probably to help them find food and avoid predators in the snow. Dominy points to even newer research showing that reindeer's eyes change with the seasons, in a manner that is thought to allow them to see better at short wavelengths in an Arctic winter.
Dominy breaks new ground in pointing out that these adaptations would be unhelpful in foggy conditions. Fog interferes with all light, but with shorter wavelengths the most, giving long wavelength red light the best chance of being seen through fog. As a positive survival trait, Dominy suggests red noses are likely to be selected for, and spread through the reindeer gene pool, with the caveat that global warming is making fog rarer.
Dominy notes, however, that there is a price to be paid for Rudolph's single headlamp. After noting that reindeer noses are a major source of lost body warmth he adds, “If too much heat is lost from his glowing nose, Rudolph could risk hypothermia under extremely cold weather conditions. It is therefore extremely important for children to provide high-calorie foods to help Rudolph maintain his body temperature on Christmas Eve.”
You've been told everyone, lay off the carrots and leave out some chocolates instead.