How to Beat the Heat

Endotherms and ectotherms have various ways to keep from getting too hot. One way is sweating. Some endotherms sweat to keep their bodies from overheating.

To sweat, nerves send messages to your brain that you are heating up. The brain then sends messages to sweat glands to produce sweat, which is mostly water. When you sweat, heat moves outside your body as water. As the water evaporates, you cool down.

Dogs don't sweat.
Instead, they pant to cool down.

Most endotherms don’t have sweat glands. Yet, they have other ways to cool down. Dogs pant. With each breath, moisture evaporates from their tongues.

Many animals use their ears to beat the heat. An elephant’s large ears have many veins. Heat from the warm blood works its way through the thin skin there and into the air. The cooled blood then circulates through the body.

This kangaroo licks its arm to keep cool.

This fennec fox uses its big ears to cool down.

Kangaroos lick their forearms to cool down. As their spit evaporates, the blood flowing close to the skin cools. It’s gross, but it works for kangaroos.

Many stay out of the hot sun, even ectotherms. Some lizards, for example, burrow into the ground to keep cool.

This iguana burrows into the soil to cool down. 

How to Turn Up the Heat

Ectotherms such as reptiles and amphibians sometimes burrow into the ground for another reason. When the weather turns cold, they hibernate. So do some insects, like ladybugs. Other insects, like monarch butterflies, fly to warmer climates.

This walrus’s layers of blubber help protect it from the cold.  

Many endotherms have another way to turn up the heat. They shiver. The brain signals muscles to vibrate. This produces heat to warm the body. Mammals and birds shiver. Some ectotherms, such as bees, shiver, too.

Many endotherms have body coverings that keep them warm. Hair, fur, or feathers keep the cold air out and the body heat in. And marine mammals grow thick layers of fat called blubber.

Endotherm vs. Ectotherm

So, which animals have the advantage to survive? If a snake was trying to catch a mouse on a cool day, the mouse probably has the advantage.

On the other hand, the snake needs a lot less food than the mouse does. The mouse has to eat every day in order to maintain its body heat. Endotherms can live almost any place on Earth. Most ectotherms can only survive in warm and mild climates.

It’s hard to say which has the upper hand. Looks like both ectotherms and endotherms have ways to survive in their environment. 

A mouse is an endotherm. A snake is an ectotherm.