The jaguar can range across a variety of forested and open habitat, but is strongly associated with presence of water.The inclusion of the United States in the list is based on occasional sightings in the southwest, particularly in Arizona, New Mexico and Texas. In the early 20th century, the jaguar's range extended as far north as the Grand Canyon, and as far west as Southern California. The jaguar is a protected species in the United States under the Endangered Species Act, which has stopped the shooting of the animal for its pelt. In 2004, wildlife officials in Arizona photographed and documented jaguars in the southern part of the state. For any permanent population to thrive, protection from killing, an adequate prey base, and connectivity with Mexican populations are essential. On February 25, 2009 a 118 lb Jaguar was caught, radio-collared and released in an area southwest of Tucson, Arizona; this is farther north than had previously been expected and represents a sign that there may be a permanent breeding population of Jaguars within southern Arizona. It was later confirmed that the animal is indeed the same male individual (known as 'Macho B') that was photographed in 2004 and is now the oldest known Jaguar in the wild (approximately 15 years old.) On Monday March 2, 2009, Macho B, which is the only jaguar spotted in the U.S. in more than a decade, was recaptured and euthanized after he was found to be suffering from kidney failure.
Completion of the United States–Mexico barrier as currently proposed will reduce the viability of any population currently residing in the United States, by reducing gene flow with Mexican populations, and prevent any further northward expansion for the species.
The historic range of the species included much of the southern half of the United States, and in the south extended much farther to cover most of the South American continent. In total, its northern range has receded 1,000 kilometers southward and its southern range 2,000 km northward. Ice age fossils of the jaguar, dated between 40,000 and 11,500 years ago, have been discovered in the United States, including some at an important site as far north as Missouri. Fossil evidence shows jaguars of up to 190 kg (420 lb), much larger than the contemporary average for the animal.
The habitat of the cat includes the rain forests of South and Central America, open, seasonally flooded wetlands, and dry grassland terrain. Of these habitats, the jaguar much prefers dense forest; the cat has lost range most rapidly in regions of drier habitat, such as the Argentinian pampas, the arid grasslands of Mexico, and the southwestern United States. The cat will range across tropical, subtropical, and dry deciduous forests (including, historically, oak forests in the United States). The jaguar is strongly associated with water and it often prefers to live by rivers, swamps, and in dense rainforest with thick cover for stalking prey. Jaguars have been found at elevations as high as 3,800 m, but they typically avoid montane forest and are not found in the high plateau of central Mexico or in the Andes.
Substantial evidence exists that there is also a colony of non-native melanistic leopards or jaguars inhabiting the rainforests around Sydney, Australia. A local report compiled statements from over 450 individuals recounting their stories of sighting large black cats in the area and confidential NSW Government documents regarding the matter proved wildlife authorities were so concerned about the big cats and the danger to humans, they commissioned an expert to catch it. The three-day hunt later failed, but ecologist Johannes J. Bauer warned: "Difficult as it seems to accept, the most likely explanation is the presence of a large, feline predator. In this area, [it is] most likely a leopard, less likely a jaguar."