Rudolph the red-nosed ruminant

Reindeer are key to Christmas, taking Santa around the world every Christmas Eve. But the rest of the year they are happy to hang around in the Northern hemisphere, which has led to some pretty unusual adaptations, including a complete lack of a body clock. But do they really have red noses, and can carrots feature in their diet? Felicity Bedford went to Scotsdale's Garden Centre, in Cambridge, to meet two reindeer, and Cambridge University Zoologist Laura Nadine Schuhmacher to find out more about Santa's sled runners...

Felicity - I'm walking through Scotsdale's Garden Centre and I'm here to find some reindeer.  At the moment, what I can see are some dancing Polar bears, there's lots of Christmas tree decorations but, as yet, no sign of reindeer...  After a bit of exploring, I found the reindeer outside, where I was joined by Laura Nadine Schuhmacher, a zoologist from Cambridge University, who explained how they cope with the cold.

Laura - As you can see we have two male reindeers here.  They are called Frost and Ice.  They have very nice soft fur - feel this.

Felicity - Oh, they are amazing.

Laura - Yes, so their thick coat keeps them warm in the winter and they actually have special hollow hairs that trap the air and keep them really warm.  And can you see this tuft of hair that they have kind of in their mid-neck?

Felicity - It's almost like a beard under their necks.

Laura -   Exactly, and this keeps them extra warm because that's around their heart and vital organ area, so that provides an extra bit of warmth for them.  Reindeer are known to have glowing red noses.  This is not completely true that there's no light shining out of their noses, but their noses are specially adapted to the cold by having extra blood vessels that warm up the air as it comes into the lungs, so they can appear a little bit red.

Felicity - So there's no real Rudolph but some reindeer, if they're feeling particularly chilly, might have a slightly red nose.

Laura - Exactly.

Felicity - Frost and Ice seem very happy living in Cambridge but, in the wild, reindeer are found around the Arctic Circle where there is constant darkness in winter and the sun never sets in summer.  Body clocks mean that most animals, including humans, are influenced by day/night cycles; this is why we get jet lagged.  Apparently, this isn't a problem for Santa's trusty steeds.

Laura - They don't have a circadian clock, so their body rhythm is different from ours.  They are not very affected by the constant dark that they experience in the Arctic.

Felicity - We're looking at these reindeer and they have the most beautiful, large eyes that are looking out at us and I'm wondering whether that might be an adaptation to the dark as well?

Laura - Yes, so, as you can imagine, if you're living in constant darkness during the winter, you don't have the same light as you have in the summer when there's constant light.  So their eyes actually change colour, which means they can increase the light capture during the winter by turning their eyes blue, while during the summer their eyes are golden.

Felicity - I've been joined by Kate, who looks after the reindeer and she's gone and got some of their food, which look like pellets.  They're extremely keen to get their food! They're right up at the fence, come to see us, and I suppose we should give them their breakfast. I note that you're not feeding them carrots.  I've heard that reindeers are very fussy eaters but they seem to be enjoying this. Is this more natural food for them?

Kate - Yes.  They can't eat carrots because of the teeth they have; they have very, very small teeth only on the bottom row so they can't chew a carrot, but they eat this pellet food.  They'll graze throughout the year- their favourite food is moss, lychen and things like that.

Felicity - These reindeer have got some really spectacular antlers on their heads, but they're looking a little bit tatty.  I understand these are both male reindeer.  Laura, perhaps you could explain to me why their antlers are looking a bit rough around the edges?

Laura - As you said, they have nicer and bigger antlers than the females. However, the male reindeer lose their antlers during the winter when it gets really cold, and the females don't.  So if you're seeing a sleigh pulled around the sky by reindeer with antlers, these are probably female because male reindeer won't have their antlers any more at this time of year.

Felicity - So it's girl power when it comes to Santa's sleigh?

Laura - Yes, pure girl power, led by Rudolph, yes!