How Do Arctic Animals Stay Warm?

Introduction

How lovely it is to come home after a chilly winter walk to a cozy house, put on your fluffy slippers, and settle by the fireplace with a warming cup of hot chocolate. Animals like the polar bear, the Arctic wolf, or Antarctic penguins are not so lucky to have such a place. How do they face the extreme winter temperatures? Most take on “winter coats” in the fall. Wondering what these coats look like, and how they help keep animals warm? Do this cool activity and you will feel it firsthand!

Background

Warm-blooded creatures like mammals—including humans—use part of the food they eat to keep their body temperatures relatively constant. A lot of energy is needed to regulate your temperature, especially when your environment is way cooler than your body temperature.

Humans use clothes to keep themselves warm on a cold day. Clothes form a thermal barrier between our warm bodies and the cold weather, preventing heat from escaping. Other mammals have developed natural barriers to trap body heat, allowing them to survive in cold climates. It is like they take on several “winter coats,” each of which plays an important part.

The first coat is often a layer of fat hidden under the skin called “blubber.” In addition to being a good thermal insulator—it does not allow heat to pass through it easily—fat has the added benefit of serving as a welcome food reserve. The next coat is often a dense layer of underfur or down feathers packed closely against the skin like a warm undershirt. This cozy, soft coat is filled with air pockets that provide insulation. A stationary layer of air is another good thermal insulator. Finally, to keep out moisture, there is often a layer of oily, water-repellent guard hairs or feathers. Sometimes these hairs appear white, but they are often transparent and hollow, which has a big advantage: they provide extra thermal insulation.

Some arctic animals, like polar bears, are so well-insulated that they cannot be spotted with night vision goggles, which pick up radiated heat. This implies that their outer layer of fur has the same temperature as their surroundings. In other words, these animals can keep all of their heat inside, losing none to the environment. How amazing!

Ready to feel the insulating capacities of these materials? Gather a few items and try it out!

Materials

Preparation

Procedure

Observations and Results

The empty bag probably felt a lot cooler than the filled bags. This is to be expected. The materials in the bags are good thermal insulators, as they do not let heat travel through them easily. Stacking two bags on top of each other creates an even bigger barrier, so it probably took longer before the top bag felt cold.

The bag with butter (a fat) probably felt colder than the bag with air or feathers, leading to the conclusion that heat transfers faster trough fat than through an equally thick layer of stationary air. Feathers insulate because they trap air, so there was probably little difference between how the bag of feathers and the bag of air felt.

People in the Arctic use animal skin and fur as well as synthetic clothes to protect themselves from the cold. Synthetic clothes made to withstand extreme weather use the same heat trapping techniques as the ones found in animals. For example, they might use down feathers to trap air, or have a water-resistant coating to keep out moisture.

More to Explore

• Cool Facts about Heat, from the Ohio State University
• How Animals Stay Warm with Blubber, from Scientific American
• New Research Reveals How Polar Bears Stay Warm, from Inside Science

Credits