Santa's Reindeer

Lesson Plan - Get It!

Audio:

There are so many myths about reindeer it's hard to know what to believe. It's time to set the truth straight.

Here are some facts about reindeer.

Fact #1: Santa's reindeer are female.

As you probably know, Santa's sled is powered by reindeer, also known as caribou. Santa uses a team of eight or nine reindeer (depending on cloud conditions).

• Does it surprise you to learn that every single one of Santa's reindeer is female?

If you look closely, you can see a specific body part that indicates all the reindeer in the photo below are female.

• Did you see the body part that indicates these reindeer are female?

Antlers! Only male deer grow antlers in most deer species. However, many types of female reindeer also grow their own set of antlers each year.

Male reindeer lose their antlers at the beginning of winter, but female reindeer do not shed their antlers until summer.

So if you see a reindeer with antlers on December 25th, it is most likely a female. You go, reindeer! Pull that sleigh!

Fact #2: Reindeer fur is lighter than you might think.

An average adult female reindeer weighs about 200 pounds. Scientists have yet to discover how a reindeer can fly, but their fur might give us some answers.

Reindeer have two types of fur to keep them warm. Some other mammals, including certain breeds of dog, also have two layers of fur — an undercoat and an overcoat.

The overcoat remains full year-round, but the undercoat grows thicker in winter. Interestingly, if an animal only has one layer of fur, it is referred to as a hair coat rather than a fur coat.

The inside fur of a double coat is called the undercoat. It is dense and woolly and exists to keep the reindeer warm, similar to the fuzzy sweater you wear when it's cold outside.

The outside fur, or topcoat, repels water, shields from dirt, and insulates. If your sweater represents an undercoat, then a puffy jacket would best represent a reindeer topcoat.

A reindeer's topcoat has an interesting quality — it's hollow. Each hair is similar to a small, air-filled tube. This space provides the reindeer with even more insulation.

Although filled with fluff, a puffy jacket is mostly air. You can see this by squeezing a puffy jacket. You should be able to compress it to a fraction of its original size.

The reindeer's hollow fur makes it much more buoyant. In other words, reindeer can float and swim more efficiently because their fur has a low density.

• Does this give reindeer the power to fly?

No, but it would make it a lot easier!

Fact #3: A reindeer's nose really can glow red.

• Reindeer fur keeps them warm, but what about when they become too warm?

It's not like they can remove their coats like we can, so reindeer have evolved another way.

Researchers in Sweden used thermal imaging cameras to observe reindeer as they graze. A thermal imaging camera is a camera that detects infrared radiation, also known as heat, and shows it as visible light.

Researchers found that the reindeer were very well insulated. Almost no heat was seen coming off of the reindeer's fur. Their fur is such a good insulator that they can lie in the snow without melting it.

However, researchers did see heat escaping from the reindeer's bodies — through their noses.

Reindeer have a lot of blood vessels in their noses and lips. They have 25% more blood vessels in their noses than humans do.

This keeps their noses and mouths warm to smell and rummage through the snow to get food. When the blood travels through these blood vessels, much of its heat leaves the vessels and escapes into the air.

This high concentration of blood vessels is often visible, causing the reindeer's noses to appear pink or red. Like this Norwegian Arctic region reindeer.

• Rudolph? Is that you?!

Watch the video below for more information on this phenomenon.

Now, assess your level of reindeer expertise in the Got It? section.