Behavior is an important aspect of an organism's evolutionary history. It dictates when and where mating will occur, if and how offspring will be nurtured, the types of food eaten, and the habitats lived in. Can researchers use behavioral characteristics to determine anything about the relationships between species? Some researchers argue that the closely-related species exhibit quite similar behaviors, while more distantly- related forms display radically different behaviors. In this sense, behavior would be a good (though untested) tool for constructing phylogenies. However, many other researchers state that behavior would not be a good indicator of genealogical relationships because it is plastic, labile, and easily modified. There have been many instances of behavioral modifications between species that have, for example, led to speciation. The proposed study will evaluate the phylogenetic content of behavioral data by comparing nuptial and agonistic behaviors exhibited by a group of African fishes against a more traditional phylogeny generated for these fishes from anatomical characteristics. These fish were chosen for study because numerous prior studies have been based upon them, and because of the rich repertoire of behaviors these fishes display. The results of the research will be of considerable interest to behavioralists, systematists, evolutionary biologists, and psychologists interested in the question of 'nature vs. nurture.'