The jaguar (Panthera onca, or /ˈdʒæɡjuˌɑː/ in British English, or /ˈdʒæɡwɑr/ in American English) 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. It is the only Panthera found in the New World. The jaguar is the third-largest feline after the tiger and the lion, and on average the largest and most powerful feline in the Western Hemisphere. The jaguar's present range extends from Mexico across much of Central America and south to Paraguay and northern Argentina. Other than occasional visits from wandering jaguars from Mexico, the cat has largely been extirpated from the USA since the early 1970s.

This spotted cat most closely resembles the leopard physically, although it is usually larger and of sturdier build and its behavioural and habitat characteristics are closer to those of the tiger. While dense rainforest 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: it bites directly through the skull of prey between the ears to deliver a fatal blow to the brain.

The jaguar is a near threatened species and its numbers are declining. Threats include habitat loss and fragmentation. While international trade in jaguars or their parts is prohibited, the cat is still regularly killed by humans, particularly in conflicts with ranchers and farmers in South America. Although reduced, its range remains large; given its historical distribution, the jaguar has featured prominently in the mythology of numerous indigenous American cultures, including that of the Maya and Aztec.

Etymology

The etymology of the word jaguar is unclear. Some sources suggest a borrowing from the South American Tupi language to English via Portuguese, while others attribute the term to the related Guaraní languages. In the Tupi language, the original and complete indigenous name for the species is jaguara, which has been reported as a denotation for any carnivorous animal —in the compound form jaguareté, -eté means "true". In the related Guaraní languages, yaguareté has been variously translated as "the real fierce beast", "dog-bodied", or "fierce dog". Early etymological reports were that jaguara means "a beast that kills its prey with one bound", and this claim persists in a number of sources. However, this has been challenged as incorrect. In many Central and South American countries, the cat is referred to as el tigre ("the tiger").