An alpha male or alpha female is the individual in the community to whom the others follow and defer. Humans and their nearest species-relatives, the chimpanzees, show deference to the alpha of the community by ritualized 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 male in their pack , by allowing him to be the first to eat and the first to mate. Wolves are a well known example of this.

The status of alpha is generally achieved by means of superior physical prowess. However in certain highly-social species such as the Bonobo apes, the alpha can use more indirect methods (such as political alliances) to oust the ruling alpha and take his/her place.

Source

• Bonobo page