Why do animals need warmth?

Not all animals need the warmth of their environment. Many animals are adaptable to cold temperatures, and some can only live in cold waters or areas. But for everyone else, heat is needed for the normal functioning of the body, since at a certain temperature blood flows normally, proteins are synthesized, the digestive process proceeds normally, and so on. A person needs warmth, since without it the body does not function and begins to spend all its energy to maintain body temperature. The same applies to other warm-blooded animals.