Recognised as the third biggest cat in the world behind the tiger and the lion, the Jaguar is the largest cat species in the Americas, closely related to the leopards, with several similar characteristics, including the distinctive spotted pattern on their pale yellow to tan coloured fur. However, they are generally more robust than the leopards, with stronger limbs and a more square head. It also has powerful jaws with the third-highest bite force, after the tiger and the lion. The rosettes on the coat of a jaguar are larger, darker, fewer in number and have thicker lines, with a small spot in the middle.

The name Jaguar is believed to be derived from the Tupi-Guarani word Yaguara, which stands for the beast that overcomes the victim with a leap. They are swift and agile and are very good climbers. However, they are also expert swimmers and appear to enjoy bathing. Although active during the day, they mainly hunt at night and on the ground. Unfortunately, despite their incredible strength, power and incredible agility, Jaguars have been hunted through the ages mainly for their soft and beautiful fur. Although hunting of Jaguar is now prohibited, their population has declined in many of their natural range and they have completely disappeared from several areas.

The lineage of the jaguar appears to have originated in Africa and it is estimated that the ancestors of the modern jaguars probably entered the Americas by crossing a land bridge that once spanned the Bering Strait. Although today their range extends from extreme southern Arizona, across Mexico to northern Argentina, and they inhabit a variety of forested and open terrains, scrublands and deserts, primarily their preferred regions are the tropical and subtropical moist forests, wetlands and wooded regions.

Nevertheless, today the jaguar is virtually extinct in the northern part of its original range, which includes El Salvador and Uruguay, and survives in reduced numbers only in remote areas of Central and South America, while its largest known population exists in the Amazon Rainforest. Threatened by habitat loss, habitat fragmentation and illegal poaching for its body parts, the jaguar has been included as Near Threatened on the International Union for Conservation of Nature Red List since 2002. At the same time, 51 Jaguar Conservation Units (JCU), inhabited by at least 50 breeding jaguars, were arranged in 36 geographic regions ranging from Mexico to Argentina.

The jaguar is a compact and well-muscled animal that stands around 2.50 feet (70 cm) tall at the shoulders. The length from its nose to the base of the tail varies from 3 feet 8 inches to 6 feet 1 inch (1.12 to 1.85 m), and a tail of around 2.5 feet (76 cm). The male jaguar, which is generally larger than the female, weighs from 100 to 160 kg (220 to 350 pounds), while the smallest females weigh about 36 kg (79 lb). The jaguars have powerful jaws and sharp teeth with the third-highest bite force, after the tiger and the lion. Their coat ranges from pale yellow to tan or reddish-yellow, with a whitish underside and covered with black spots, which also vary and may include one or several dots. Generally, the spots on the head and neck are solid, as are those on the tail, where they may merge to form bands near the end and create a black tip. The spots are elongated on the middle of the back, often creating a pattern of median stripes, which help them to camouflage in the forest. The roar of a male jaguar sounds more like a bark, followed by a growl, but a female produces a peculiar sound, almost like a coughing roar.

The jaguar is strictly a carnivorous animal, solely depending on flesh for its nutrient requirements, but its diet is dependent on the availability of prey. They are agile and opportunistic hunters and can prey upon almost anything they come across. They tend to take larger prey, usually over 22 kg (49 lb) and seem to prefer deer and calves. Apart from that, they often take capybara, tapir, monkey and peccary, a gregarious pig-like mammal.

In floodplains, jaguars consume reptiles more frequently than any other big cats and opportunistically take turtles and caimans, a semi-aquatic reptile similar to the alligator. It has been recorded that one remote population of jaguar in the Brazilian wetland area primarily feed on aquatic reptiles and fish. However, where wild prey is scarce, they also prey on livestock in the cattle ranching areas.

Except for females with cubs, the jaguar is generally solitary. Males establish their territories twice as large as females, overlapping the ranges of several females and both sexes mark their territories with scrape marks, urine and faeces. During her oestrus, the female exhibits increased restlessness with rolling and prolonged vocalizations to attract a male in her territory. The mating pair stays together for around five days, when they couple up to one hundred times in a single day, to ensure that copulation will be successful. After a gestation period of about 91 to 111 days, the female typically gives birth to one or two cubs. Once the cubs are born, the female Jaguar becomes very protective, does not tolerate even the male partner in her territory and raises her cubs alone. The helpless cubs are born with closed eyes and gain their sight after about two weeks. They are weaned at the age of three months, but remain in the confinement for six months, before leaving to accompany their mother on hunts. However, they remain with their mothers for up to two years, when they become ready to claim their own territory. The jaguar cubs reach sexual maturity at the age of two to three, can live around 12 years in the wild, but their lifespan may be extended to over 20 years in captivity.