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, such as frogs, toads, salamanders,  newts, and gymnophiona, are cold-blooded animals that metamorphose  from a juvenile, water-breathing form to an adult, air-breathing  form.nlike other land  animals (amniotes), amphibians lay eggs in water, as their fish  ancestors did. Amphibians are superficially similar to  reptiles.    Amphibians are cold-blooded animals, meaning they do not have a  constant body temperature but instead take on the temperature of  their environment.