One of my favorite holiday traditions as a child was watching the amazingly adorable (and horrible claymation) Christmas special, “Rudolph the Red-nosed Reindeer” which always aired every December on one of the three prime-time networks (this was way back in the dark ages of television when there were only ever 3-5 channels to watch anyway). The tale of that poor, little, “mutant” deer overcoming the adversity of the bullying he received, forgiving the culture that ridiculed him, and finding his place in their world was, and still is, an uplifting storyline. As I watched it again last night with my son, I was reminded of the clear message it wrought and the cultural changes that have occurred since I was a kid (as my son commented that “if HE were Santa, HE wouldn’t have treated Rudolph like that in the first place). Of course, my son was also less impressed with the show than I had ever been at his age since the movie “didn’t really have a bad guy that the hero needed to catch/fight/overcome/whatever” and that the Abominable Snowman didn’t count.

However, since I am a science geek, I began to wonder exactly why or how a reindeer might be born with a red nose in the first place. Reindeer typically have large, black noses (as you can see to the right here) and it’s not really a light bulb type of nose either, set up to hi-beam around in a blizzard. So barring the physics involved (as I’m not much of an engineer), I was still biologically curious to know if this could have been a wild mutation, random and unlikely to occur, or if there was, in fact, some kind of genetic underpinning that could have led to this marvel of evolution.

Serendipitously, I received a random email this morning pointing me toward a fun, little research article from a group in the Netherlands, led by Can Ince, entitled “Why Rudolph’s nose is red: observational study”. According to the paper, reindeer have a “rich vascular anatomy with a high functional density of microvessels” in their noses, which leads to a continuous level of sensitivity and function even as the reindeer spend enormous amounts of time with their noses buried in the snow, searching for food. Ince and colleagues found that the microcirculation of the nasal mucosa in reindeer is 25% denser than humans and can actually be visualized as areas of higher temperatures in thermographic pictures! In a related comparison, another group from Sweden (the Mammalian Rhinarium Group) is using a thermographic camera to study mammals and why some developed the rich, blood-filled noses while others (like dogs) evolved wet, cold tipped rhinaria (that’s that hairless, outer tip of the nose of many mammal species like dogs or cats).

Still, according to Ince, ALL reindeer have this blood-dense mucosa…and their noses remain black as coal. But I am reminded that there are animal species which have evolved specialized blood vessels in various parts of their anatomy. For instance, alligator snapping turtles use the blood coursing through their bright, red, pulsating tongue to act as a lure for unassuming fish to be drawn closer to the turtle’s gaping mouth. Such an evolutionary leap might have been possible due to a rich density of blood vasculature already present in the species from which the mutation was able to springboard. One small bit of evolutionary pressure later, and VOILÀ! We have turtles with pulsating worms for tongues!

So does that make the possibility of a bright, shiny reindeer nose more probable? Well, evolution has certainly produced stranger things. It may be that Rudolph has an evolutionary advantage over the other reindeer. With a brightly glowing nose, it may be easier for female reindeer to locate him in blizzard like weather. Or, with even more blood pouring through his nose than a normal reindeer, it may be easier for him to locate snow-buried food. Or maybe the original story was only partially right, and the truth is that Santa has been carefully cross-breeding his reindeer for years in order to eventually develop an eight-reindeer team of fog-busting reindeer. It’s difficult to discover the truth. And only time will tell if this is a genetic advantage worth perpetuating.

But my guess is that we will start seeing herds of red-nosed reindeer at some point in the future.

Ince, C., van Kuijen, A. M., Milstein, D. M., Yürük, K., Folkow, L. P., Fokkens, W. J., & Blix, A. S. (2012). Christmas 2012: Research: Why Rudolph’s nose is red: observational study. BMJ: British Medical Journal, 345.

(Bonus video below is from an interview with Professor Ronald Kröger with the Mammalian Rhinarium Group in Sweden!)

Happy Holidays!

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