Any relationship between two species of animals is symbiosis and includes both positive and negative interactions. The different forms of symbiosis each have their own names. Both species benefit by the interaction between the two species. One species benefits from the interaction and the other is unaffected.
Examples are predation, parasitism, and disease.
Both species are adversely affected by the interaction. This page deals only with mutualism and commensalism. Predation and competition are treated on separate pages of Nearctica . Symbiosis in the Forest . Slone K. Pearson et al.