MICROANATOMY

Detailed explanation-1: -Mammals are vertebrate animals that are endothermic, have hair on their bodies, and produce milk to feed their babies. Many mammals give birth to live young that are small and helpless.

Detailed explanation-2: -Hair (and a coat of hairs, called fur or pelage) is uniquely mammalian. No other creature possesses true hair, and at least some hair is found on all mammals at some time during their lives. Hairs grow out of pits in the skin called follicles.

Detailed explanation-3: -In order to help maintain their body temperature in cold weather, endothermic animals can have a layer of insulation to keep their heat in, such as fur, feathers, or even a thick layer of fat called blubber!

Detailed explanation-4: -All mammals have hair. It is one of their defining biological characteristics. However, there are a few species with hair so reduced by evolution that they actually appear to be naked.