In the animal kingdom, competition is a part of life. Dominance hierarchies are common both within a group in a species (intergroup) or between two different species (interspecific). These hierarchies often result in aggression as the groups fight for dominance. It would make sense, therefore, that two species who are similar in status in the dominance hierarchy would have an unstable relationship and therefore engage in interspecific aggression continuously over time. One example of two species consistently engaging in interspecific aggression to establish dominance would be the Atlantic spotted dolphins (Stenella frontalis) and Atlantic bottlenose dolphins (Tursiops truncatus).