Why animals color is different from …

Some animals are colored for physical protection, with pigments in the skin to protect against sunburn, while some frogs can lighten or darken their skin for temperature regulation. Finally, animals can be colored incidentally. For example, blood is red because the heme pigment needed to carry oxygen is red. Animals colored in these ways can have striking natural patterns.

Animals produce color in both direct and indirect ways. Direct production occurs through the presence of visible colored cells known as pigment which are particles of colored material such as freckles. Indirect production occurs by virtue of cells known as chromatophores which are pigment-containing cells such as hair follicles. The distribution of the pigment particles in the chromatophores can change under hormonal or neuronal control. For fishes it has been demonstrated that chromatophores may respond directly to environmental stimuli like visible light, UV-radiation, temperature, pH, chemicals, etc.