Skin is the soft outer covering of vertebrates. Other animal coverings such as the arthropod exoskeleton or the seashell have different developmental origin, structure and chemical composition. The adjective cutaneous means "of the skin" (from Latin cutis, skin). In mammals, the skin is the largest organ of the integumentary system made up of multiple layers of ectodermal tissue, and guards the underlying muscles, bones, ligaments and internal organs. Skin 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. Because it interfaces with the environment, skin plays a key role in protecting the body against pathogens and excessive water loss. Its other functions are insulation, temperature regulation, sensation, and the protection of vitamin D folates. Severely damaged skin may heal by forming scar tissue. This is often discoloured and depigmented.
The wildlife of Tanzania refers to the flora and fauna of Tanzania. Tanzania contains some 20 percent of the species of Africa’s large mammal population, found across its 14 national parks, reserves, conservation areas and marine parks, spread over an area of more than 42,000 square kilometres (16,000 sq mi) and forming more than one-third of the country's territory. Wildlife resources of Tanzania are described as "without parallel in Africa" and "the prime game viewing country". Serengeti National Park, the largest declared park area of 14,763 square kilometres (5,700 sq mi), is located in northern Tanzania and is famous for its extensive migratory herds of wildebeests and zebra while also having the reputation as one of the great natural wonders of the world. Ngorongoro Conservation Area, established in 1959 with an area of 8,094.4 square kilometres (3,125.3 sq mi), listed as a UNESCO World Heritage Site, is inhabited by the Masai. Its Ngorongoro Crater is known as the "largest intact caldera in the world".
The national parks are also part of the wetlands of Tanzania. The wild animals tend to be closer to the wetlands, particularly the water loving species such as the hippopotamus, waterbuck, warthog, elephant, crocodile, sitatunga as well as water birds such as flamingoes and ducks.