Color Change According to the Environment

Do living creatures only make use of color to protect themselves against their enemies? Definitely not. Some animals protect themselves also from cold and heat by means of enzymes giving color to the hairs covering their bodies. In animals that live in cold regions, the hairs covering the tip of the legs, ear and nose, which are the most sensitive parts of the body, are dark colored. Dark colored hairs provide more heat energy for animals thus helping them to warm easier, just like humans who try to benefit from the sun better by wearing dark colored clothes in winter. Color change is very common in land animals. For example, in summer, the fur of the northern fox turns white, because their body temperature is high. In winters, however, as it becomes colder, their body temperature drops and a more suitable environment for the enzymes to work easily is provided. For this reason, in winters, the fur of the northern fox darkens. Rabbits, foxes, weasels, and polecats living in northern latitudes turn brown in summer and white in winter.

While some birds become completely white in winter months, they take on a new appearance in spring matching the color of the ground and vegetation.

Warning Colors

Living creatures make use of color for varied purposes. Using it as a mean of warning is one of these purposes. In the following pages, we will give some examples of this.

Colors in Birds

One of the most important features of the multicolored feathers of birds is that they are lifeless structures. The reason why a feather maintains its color exactly, even after it is shed, is that a fully developed feather is completely lifeless.

Rich color diversity in birds is basically due to the presence of pigments in the feathers, which were stored during the initial development phases of the feather, or the light shifts which occur depending on the structural characteristics of the feathers.

Since these formations, which are made up of the substance keratin, are soon worn down by environmental conditions, they are regularly renewed. Yet, each time, the bird regains its colorful feathers. This is because the feathers of birds continue to grow until they fully reach the necessary length, and the characteristic color and pattern of that specific kind.

Due to their different structure, feathers can have an appearance similar to that obtained by a glass prism breaking light into different colors. Colors that are formed through refraction of light in this way are brighter and more metallic than those that are colored by pigments. The colors of these feathers shift from blue to green, and from orange to red. Generally, the green, blue, and metallic colors in birds are formed through the reflection and refraction of light. Yet, some of the colors of feathers come from pigments.

There are mainly three kinds of pigments in birds. These are melanin pigments that produce black, brown or dull yellow, lipochrome pigments that produce red, yellow or orange, and carotenoids. Blue, green and some other bright colors in birds are created by microscopic bubbles in the keratin of the feathers that refract the light. The feathers absorbing the full spectrum of light and only reflecting blue, on the other hand, creates the blue color of some birds.

Hormones also play an important role in color change in birds. The color difference between the male and female members of some species is caused by sex hormones. The different colorings and feather shapes of cocks and hens, for example, depend on the estrogen hormone.

The colors of birds are important for their adaptation to their habitat as well as for male and female members' recognition of each other and the males' courtship of females in the mating season. In addition, pigments, which give color to feathers, enhance the strength of the feathers, store energy coming from the sun and prevent harmful ultraviolet rays from entering the body.