Earlier in the Christmas season, I posted a Bitstrips comic on my personal Facebook page joking about the genetics of Rudolph’s nose. In response, a friend sent a link to this article on a 2012 study on red noses in reindeer. As part of the study, thermal images were taken of red-nosed reindeer.
From the original paper, published in the British Medical Journal, here is the conclusion:
The nasal microcirculation of reindeer is richly vascularised, with a vascular density 25% higher than that in humans. These results highlight the intrinsic physiological properties of Rudolph’s legendary luminous red nose, which help to protect it from freezing during sleigh rides and to regulate the temperature of the reindeer’s brain, factors essential for flying reindeer pulling Santa Claus’s sleigh under extreme temperatures.
The BMJ study did not address the heritability of red noses in reindeer. However, one would think that if the trait caused an individual to be excluded from reindeer games, his chance to pass it along to offspring would be considerably limited. That might explain its relative rarity in the overall reindeer population.
Merry Christmas to readers of the blog!