Biological term: countershading

Many marine life is countershaded, which is a type of their camouflage. What exactly is countershading?

Imagine you are on a boat and looking down at the sea. The sea water looks dark blue. If you were a sea animal, what color should you hide from animals in the sky or above you?

Now imagine you are scuba diving at the bottom of the ocean and looking up into the sky. During the day, sunlight penetrates the water. What color should the animal have so that it can dissolve in the water and hide from the animals beneath it?

Animals selected for countershading

Animals with a dark top and a light bottom are called countershading.

Dark-colored animals with dorsal fins are less likely to be seen and eaten by creatures in the sky or sea animals above the sea. Their dark skin blends in with the colors of the ocean around them, and they have a higher survival rate than light-colored animals on top.

Animals with a lighter color on the underside tend to blend into the ocean when looking up from the ground. They are more viable than the darker animals under the sides, as they are less likely to be found and eaten by the fish and animals beneath them in the water.

Therefore, animals with both of these functions are even more likely to live to a reproductive age.

What kind of animals are countershaded?

Countershading, in which animals blend into the background, is most common in marine animals. Sharks, dolphins, porpoises, fish and penguins all exhibit this type of countershading.

Another type of countershading has the same type of principle, but the animal does not completely blend into the background. Instead, their coloring makes it difficult for predators to see where their bodies begin and end. Some lizards and caterpillars exhibit this type of countershading.

What did you learn from animals?

An artist and naturalist named Abbott Sayer studied countershading. He described and published his natural study of countershading in 1892. In fact, countershading is sometimes referred to as Sayer’s Law. Sayre contributed in World War I by proposing that the military use countershading technology to paint ships.

Countershading and camouflage techniques are frequently used by the military. Clothing fashion is also influenced by these types of color schemes.