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Mammal, common name applied to any warm-blooded animal belonging to the class that includes humans and all other animals that nourish their young with milk, that are covered with varying amounts of hair, and that possess a muscular diaphragm. have the most highly ....

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.... are often less than 5 cm (less than 2 in) in length. In many mammals the color of the skin or fur blends with the animal’s natural surroundings. In others there is great contrast with the natural surroundings to favorvisual signals that provide information about theidentity of a species, and about the gender, age, orsocial status of an individual. The skin also functions as a sensory and excretory organ and contains specialized glands. Mammary glands, which are present in fully developed form in all adult female mammals. Aquatic mammals, such as whales, dolphins, and sea cows, have no sweatglands. Sweat glands are usually located at the b ....