Grey wolves have long embodied the spirit of the wilderness. Once they had the largest natural distribution of any mammal except humans. Sadly, they can no longer claim this record as they have been lost from much of their former lands. Grey wolves still occupy a range of habitats including Arctic tundra, prairies and forests.
Although melanin is found in the skin of many species, in the reptiles, the amphibians, and fish, the epidermis is often relatively colourless. Instead, the colour of the skin is largely due to chromatophores in the dermis, which, in addition to melanin, may contain guanine or carotenoid pigments.kin of a different nature exists in amphibians, reptiles, and birds. All mammals have some hair on their skin, even marine mammals which appear to be hairless. The skin interfaces with the environment and is the first line of defense from external factors.
Amphibians are vertebrate animals residing in a wide range of habitats, such as aquatic, terrestrial, and arboreal. Evolution of the earliest amphibians took place in the Devonian period; their features modified over a period of time. While some are extinct, following are the characteristics of the extant species of class Amphibia. Â» The color of the skin of amphibians is a result of three layers of cells called chromatophores. 1  Deepest layer is made up of melanophores. 2  Intermediate layer consists of guanophores giving the organism the blue-green color.  Topmost layer consists of lipophores, which give the yellow color to the organisms.