"Being civilized and human means, for one thing, that our lives are not ruled by smells. The social behavior of most animals is controlled by smells and other chemical signals. Dogs and mice rely on odors to locate food, recognize trails and territory, identify kin, find a receptive mate. Social insects such as ants send and receive intricate chemical signals that tell them precisely where to go and how to behave at all times of day.
But humans "see" the world largely through eyes and ears. We neglect the sense of smell—and often suppress our awareness of what our nose tells us. Many of us have been taught that there is something shameful about odors.
Yet mothers can recognize their babies by smell, and newborns recognize their mothers in the same way. The smells that surround us affect our well-being throughout our lives." ( Edited by plmiller )  

http://www.hhmi.org/senses/d110.html