Why is Rudolph's nose red?

"Rudolph the red-nosed reindeer, had a very shiny nose..." Many of us will be very familiar with Santa's famous antlered friend. But did you know that many reindeer actually do have red noses? But why? In this festive episode of the Big Questions Podcast, we ask Oxford polar biologist Ignacio (Nacho) Juarez Martinez to share some of the reasons we find red pigments in animals, and to explain why he thinks Rudolph's nose is so red!