Days of Winter Holiday Trivia: Day 22

Although the saintly Nicholas of Myra most likely never saw or heard of the creature, reindeer have long been associated with Santa. Well, since the early 1800s at least. Rudolph the Red-Nosed Reindeer, however, didn't come on the scene until 1939. That's when Robert May wrote an illustrated book for Montgomery Ward stores to hand out to children. (Johnny Marks wrote the famous song a decade later). These two sources merely state that Rudolph had a red nose and showed what happened because of that particular characteristic. Neither has any information about how Rudolph's nose got so red.

There have been several attempts at explaining Rudolph's prominent schnoz. One view is that a terrible cold caused his nose to flare up colorfully. Another, less family-friendly, story accuses Rudolph of dipping into the liquor cabinet while Santa noms on milk and cookies. Of course, some research in the late 90s uncovered a less prosaic but more convincing explanation. Your question today:

What is Norwegian scientist Odd Halvorsen's biological, and somewhat squirm-inducing, explanation for Rudolph's red nose? 

Bonus question: What is the problem with most representations of reindeer on Christmas cards?  

Do you have an answer to submit? See the notes below for details on how to participate in my 25 Days of Winter Holiday Trivia (and maybe win a gift card)!


Contest Notes:

Remember, my 25 Days of Winter Holiday Trivia is an actual contest. If you want to participate, all you have to do is send me your answer to each question I've posted (and for which I have not yet posted the answer). I'll start posting answers on Wednesday, but will likely only go through the first week of trivia. So you still have time to go back through the posted questions and rack up some points.

Points? Yes! The three folks who rack up the most points in my trivia game will receive a gift card!

If you want to participate, simply message me your answers. Don't post in the comments unless you don't mind sharing your work. (Just DM me on Twitter, private message me on FB, or use the contact info on this blog to email me).