The jaguar (/ˈdʒæɡjuːər, ˈdʒæɡjʊər, ˈdʒæɡjuːɑr/ or /ˈdʒæɡwɑr/; Brazilian Portuguese: [ʒɐˈɡwaʁ], Spanish: [xaˈɣwar]), Panthera onca, is a big cat, a feline in the Panthera genus, and is the only extant Panthera species native to the Americas. The jaguar is the third-largest feline after the tiger and the lion, and the largest in the Americas. The jaguar’s present range extends from Southwestern United States and Mexico across much of Central America and south to Paraguay and northern Argentina. Apart from a known and possibly breeding population in Arizona (southeast of Tucson) and the bootheel of New Mexico, the cat has largely been extirpated from the United States since the early 20th century.

This spotted cat most closely resembles the leopard physically, although it is usually larger and of sturdier build and its behavioral 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 terrains. 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 largely a solitary, opportunistic, stalk-and-ambush predator at the top of the food chain (an apex predator). It is a keystone species, playing an important role in stabilising ecosystems and regulating the populations of the animals it hunts. The jaguar has 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 bite to the brain.

The jaguar is a near threatened species and its numbers are declining. Threats include loss and fragmentation of habitat. While international trade in jaguars or their parts is prohibited, the cat is still frequently 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 those of the Maya and Aztec.

The word ‘jaguar’ comes to English from one of the Tupi–Guarani languages, presumably the Amazonian trade language Tupinambá, via Portuguese jaguar.[6] The Tupian word, yaguara “beast”, is sometimes translated as “dog”.[7][8] The specific word for jaguar is yaguareté, with the suffix -eté meaning “real” or “true”.

The first component of its taxonomic designation, Panthera, is Latin, from the Greek word for leopard, πάνθηρ, the type species for the genus. This has been said to derive from the παν- “all” and θήρ from θηρευτής “predator”, meaning “predator of all” (animals), though this may be a folk etymology—it may instead be ultimately of Sanskrit origin, from pundarikam, the Sanskrit word for “tiger”.

Onca is the Portuguese onça, with the cedilla dropped for typographical reasons, found in English as ounce for the snow leopard, Panthera uncia. It derives from the Latin lyncea lynx, with the letter L confused with the definite article (Italian lonza, Old French l’once).

Taxonomy and evolution
The jaguar, Panthera onca, is the only extant New World member of the Panthera genus. DNA evidence shows the lion, tiger, leopard, jaguar, snow leopard, and clouded leopard share a common ancestor, and that this group is between six and ten million years old; the fossil record points to the emergence of Panthera just two to 3.8 million years ago. Phylogenetic studies generally have shown the clouded leopard (Neofelis nebulosa) is basal to this group. The position of the remaining species varies between studies and is effectively unresolved.

Based on morphological evidence, British zoologist Reginald Pocock concluded the jaguar is most closely related to the leopard. However, DNA evidence is inconclusive and the position of the jaguar relative to the other species varies between studies. Fossils of extinct Panthera species, such as the European jaguar (Panthera gombaszoegensis) and the American lion (Panthera atrox), show characteristics of both the lion and the jaguar.[17] Analysis of jaguar mitochondrial DNA has dated the species’ lineage to between 280,000 and 510,000 years ago, later than suggested by fossil records.

Asian ancestry
While jaguars now live only in the Americas, they are descended from Old World cats. Two million years ago, scientists believe, the jaguar and its closest relative, the similarly spotted leopard, shared a common ancestor in Asia. In the early Pleistocene, the forerunners of modern jaguars crossed Beringia, the land bridge that once spanned the Bering Strait and connected Asia and North America. These jaguar ancestors then moved south into Central and South America, feeding on the deer and other grazing animals that once covered the landscape in huge herds.

Geographical variation
While numerous subspecies of the jaguar have been recognised, recent research suggests just three. Geographical barriers, such as the Amazon river, limit gene flow within the species.
The last taxonomic delineation of the jaguar subspecies was performed by Pocock in 1939. Based on geographic origins and skull morphology, he recognized eight subspecies. However, he did not have access to sufficient specimens to critically evaluate all subspecies, and he expressed doubt about the status of several. Later consideration of his work suggested only three subspecies should be recognised.

Recent studies have also failed to find evidence for well-defined subspecies, which are no longer recognised. Larson (1997) studied the morphological variation in the jaguar and showed there is clinal north–south variation, but also the differentiation within the supposed subspecies is larger than that between them, and thus does not warrant subspecies subdivision. A genetic study by Eizirik and coworkers in 2001 confirmed the absence of a clear geographical subspecies structure, although they found that major geographical barriers, such as the Amazon River, limited the exchange of genes between the different populations. A subsequent, more detailed study confirmed the predicted population structure within the Colombian jaguars.

Pocock’s subspecies divisions are still regularly listed in general descriptions of the cat. Seymour grouped these in three subspecies.

Panthera onca onca: Venezuela through the Amazon, including
P. o. peruviana (Peruvian jaguar): Coastal Peru
P. o. hernandesii (Mexican jaguar’): Western Mexico – including
P. o. centralis (Central American jaguar): El Salvador to Colombia
P. o. arizonensis (Arizonan jaguar): Southern Arizona to Sonora, Mexico
P. o. veraecrucis: Central Texas to southeastern Mexico
P. o. goldmani (Goldman’s jaguar): Yucatán Peninsula to Belize and Guatemala
P. o. palustris (the largest subspecies, weighing more than 135 kg or 300 lb): The Pantanal regions of Mato Grosso and Mato Grosso do Sul, Brazil, along the Paraguay River into Paraguay and northeastern Argentina.
The Mammal Species of the World continues to recognize nine subspecies, the eight subspecies above and additionally P. o. paraguensis.