Keystone species mussel population explodes uncontrollably, driving out most other species. These creatures need not be apex predators. Sea stars are prey for sharks, rays, and sea anemones. Sea otters are prey for orca. The jaguar, whose numbers in Central and South America have been classified as near threatened, acts as a keystone predator by its widely varied diet, helping to balance the mammalian jungle ecosystem with its consumption of 87 different species of prey. The lion is another keystone species. Keystone mutualists are organisms that participate in mutually beneficial interaction and the loss of which would have a profound impact upon
Apex predator Cambrian period when animals such as "Anomalocaris" dominated the seas. Humans have for many centuries interacted with apex predators including the wolf, birds of prey and cormorants to hunt game animals, birds, and fish respectively. More recently, ecotourism such as with the tiger shark has become popular, and rewilding with predators such as the lynx has been proposed. Apex predators affect prey species' population dynamics and populations of other predators, both in aquatic and in terrestrial ecosystems. Non-native predatory fish, for instance, have sometimes devastated formerly dominant predators. A lake manipulation study found that when the non-native smallmouth bass was