Apex predators are top-tier members of complex ecosystems and their presence is indicative of a healthy environment. Generally, apex predators occur at the highest trophic levels of their ecosystems and lack any natural predators within it. These predators have a substantial influence on overall ecosystem structure and the populations of lower trophic levels, and their existence is often a necessary component of maintaining overall balance and biodiversity. Apex predators can be both vertebrates and invertebrates, but their respective roles are often similar, regardless of species. Without apex predators, ecosystems may become imbalanced, abnormal, or diminished.

See also: arms race, game theory, superorganism