Jaguar

The jaguar 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 Paraguayand 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. Its preferred habitats are usually swamps and wooded regions, but jaguars also live in scrublands and deserts. 
The jaguar 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 stabilizing 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 armored 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. The Tupian word, yaguara beast, is sometimes translated as dog.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

alland θήρ from θηρευτής "predator", meaning predator of all  animals, though this may be a folketymology may instead be ultimately of Sanskrit origin, from pundarikam, the Sanskrit word for tiger. In Mexican Spanish, its nickname is el tigre: 16th century Spaniards had no native word in their language for a cat smaller than a lion but bigger than a leopard nor had ever encountered such a creature in the Old World, and so named it after a cat whose ferocity would have only been known to them through Roman writings, popular literature during the Renaissance.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.