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
Barbary macaque Europe is that of Gibraltar, which, unlike that of North Africa, is thriving. Currently, there are around 230 individuals living on the Rock of Gibraltar, and they form groups of up to 75 and will occasionally enter the town. Barbary macaque The Barbary macaque ("Macaca sylvanus"), also known as Barbary ape or magot, is a species of macaque unique for its distribution outside Asia. Found in the Atlas Mountains of Algeria and Morocco along with a small population of uncertain origin in Gibraltar, the Barbary macaque is one of the best-known Old World monkey species. The Barbary macaque is of