In social animals, the alpha male is the individual in the community to whom the others follow and defer. In some groups, the alpha males are overrepresented in the genetics of a population if they are the only ones who breed successfully.

Chimpanzees show deference to the alpha of the community by ritualised gestures such as bowing, allowing the alpha to walk first in a procession, or standing aside when the alpha challenges. Canines also show deference to the alpha in their pack, by allowing them to be the first to eat.

The status of the alpha is generally achieved by means of superior physical prowess; however, in certain highly social species such as the bonobo and humans, a contender can use more indirect methods, such as political alliances, to oust the ruling alpha and take his place.

Courtesy of Wikipedia.