Beyond their sled-pulling capabilities and discrimination against those with red noses, what do you really know about reindeer?

Five years ago DMX changed the holidays forever after a video went viral of him rapping the lyrics to "Rudolph the Red-Nosed Reindeer" with the full spirit of Christmas behind him. It was ...

Do reindeer's eyes really change color? If so, why, and how does this adaptation actually work in the wild?