The jaguar (Panthera onca) (Brazilian Portuguese: onça pintada) is a New World mammal of the Felidae family and one of four "big cats" in the Panthera genus, along with the tiger, lion and leopard of the Old World. The jaguar is the third-largest feline after the tiger and lion, and is the largest and most powerful feline in the Western Hemisphere. The jaguar's present range extends from Mexico (with occasional sightings in the southwestern United States) across much of Central America and south to Paraguay and northern Argentina.
The spotted cat most closely resembles the leopard physically, although it is of sturdier build and its behavioural and habitat characteristics are closer to those of the tiger. While dense jungle is its preferred habitat, the jaguar will range across a variety of forested and open terrain. It is strongly associated with the presence of water and is notable, along with the tiger, as a feline that enjoys swimming.
The jaguar is a largely solitary, stalk-and-ambush predator, and is opportunistic in prey selection. It is also an apex and keystone predator, playing an important role in stabilizing ecosystems and regulating the populations of prey species. The jaguar has developed an exceptionally powerful bite, even relative to the other big cats. This allows it to pierce the shells of armoured reptiles and to employ an unusual killing method with mammals: it bites directly through the skull of prey between the ears to deliver a fatal blow to the brain.