The most prominent difference from other species is the presence of mammary glands in the female of every mammal. A typical mammal maintain a constant body temperature, is covered with hair and give birth to live young.

All mammals have an internal skeleton consisting of the ribs, the skull that contains and protects the brain, a vertebral column (hence the name vertebrata), and the limb bones (legs, arms).

Mammals are all endothermic, meaning that they can maintain their body temperature, usually between 36-38°C by producing heat within their bodies.  The exception here being the Gemsbok (Oryx) that is able to raise it's body temperature way above normal to be able to live in the desert and they have veins in their noses that help them cool down, similar to a motor vehicle's radiator..

Young mammals suckle from nipples connected to the mammary glands.  Mammals have the ability to sweat through their sweat glands in the skin helping to regulate their body temperature.  Hyenas and the mongooses have anal scent glands that they use as either an attractant or in defense. Some of our antelopes like the very small Blue Duiker, even have glands under their eyes from which they mark their territories.

Some of the animals grow a thick undercoat of hair during wintertime that they shed again in summer to help them survive. Hair is dead and grows from living cells the same as nails, claws, hooves and horns. Horns are supported by a core of bone and the exception is rhinoceros horn that is entirely a product of the skin, like hair.

To summarize, mammals can regulate their body temperature, their eggs are fertilized within the female reproductive tract and their young are born at an advanced stage of development. Following their birth they are dependant on their mothers milk until they are weaned.

Now go to the "Classification of Mammals" section to really start exploring our wildlife.