Some researchers claim that animals change color in response to their environment because changing color is the easiest way to cause an optical illusion and does not need much time to hide from predators. Although this thesis was rife with controversy, a new idea emerged that refuted the previous theory. It contains the idea that protection cannot simply be a clear explanation for the color change of animals, because some researchers have found that most animals are color blind. Their color functions as a visual signal of mood or the process of evolution. To support this opinion, the explanation of the animal's physical difficulty will be discussed. As mentioned above, this thesis is very controversial. Most people believed the existing theory; The animal changes color to protect itself. Nevertheless, the new theory, that protection is not just a reason to change color, had more verifiable evidence, so many researchers are now fueling a new theory. Let us now compare the existing theory and the new theory to address the fact. Many zoological scientists have insisted that animals change color to blend into their surroundings and thus escape the attention of predators or prey. For example, polar bears' white fur helps them become less visible in the snow when they search for the ringed seals they use for food. The toad is another example. Most toads have dull coloring – brown, green, gray – to help them camouflage themselves in their surroundings. However, these claims may be denied due to physical difficulties. A major factor that disproves the protective coloring theory is that most animals do not have the ability to distinguish colors like human beings do. Animals and humans have sticks and...... middle of paper ......e two male chameleons confront each other. While the color of a superior becomes dazzling, the color of another loser becomes dark; it is a kind of expression of a feeling of superiority. It changes color to black when it gets angry, and if it changes color in a unique way, it means that mating season is approaching soon. Octopuses and squid can also change color depending on their feelings. In conclusion, animals can absolutely change color to survive, however, protective coloration cannot be a simple clear explanation of their shapes and colors. Considering the facts mentioned above, the statement that the color of the animal is the result of the belief in its survival is partly correct, however, protection is not a main point for changing its color. Nevertheless, the diversity of animal colors pleases our eyes. The path of nature is truly deep and mysterious.