The term common integument encompasses ordinary skin with its covering of hair and variety of skin glands as well as more specialized parts such as claws, hoofs, and horns.
The skin completely encloses the body and blends with the mucous membranes at the various natural openings. The integument offers protection against wear and tear as well as entry of pathogens and other environmental toxicants.
It is critical for thermoregulation (p. 343) and impermeable to water while preventing the body from drying out. Conversely, the integument prevents excessive water uptake in aquatic mammals. Certain lipid substances can penetrate skin and are used (in the form of ointments) as vehicles for administration of medication.The pigment granules in certain cells impart color to the skin, protect it against ultraviolet radiation, and reflect solar heat to protect in increases in body temperature. It is known that skin and coat color affect the adaptability of animals to life in sunny climates. The color of naked and nonpigmented areas is also affected by the perfusion of blood vessels in deeper layers, examples of which are blushing in humans, the pallor of anemia or shock, the blue tint (cyanosis) of lack of oxygen, and the yellow (icterus) of jaundice. Very spectacular color changes, such as that for which the chameleon is famous, do not occur in mammals, although mention may be made of the garish coloration of the skin of the mask and perineum of male mandrills and related monkeys.