The Jaguar (Panthera onca) is one of the four commonly agreed upon "Big Cat" species in the world, and the only one to be found in the Americas. It comes in third in size to the Tiger and the Lion, and is the largest cat in the Western Hemisphere. Although its range was once much wider, today the Jaguar can be found mostly in Mexico/Central America down to Paraguay and northern Argentina. They are hardly ever glimpsed inside the southwestern United States - a small and rarely observed breeding population in Arizona.
The Jaguar resembles the Leopard in appearance and the Tiger in behavior. They're built more solidly than the Leopard - male Jaguars can weigh in at an average of 211 pounds (96 Kg), and one especially large male specimen weighed 350 pounds (160 Kg). They measure about six feet (1.95 m) in body length, with a 30-inch tail (75 cm), the shortest of any Big Cat, proportionally. There are three generally recognized subspecies of Jaguar:
- Panthera onca onca (Venezuela, the Amazon, and Peru)
- Panthera onca hernandesii (Mexico to Guatemala)
- Panthera onca palustris (Brazil, Argentina and Paraguay)
The Jaguar is a keystone species, meaning that their existence plays an integral part in stabilizing the ecosystems in which they live. Like Tigers, they are solitary ambush predators with an extremely powerful bite - even relative to the larger Big Cats. Their bite strength allows them to pierce the shells of large turtles and deliver killing bites to the skulls of deer, caimans, capybaras, tapirs, foxes and anacondas.
Jaguars have color morphism in their populations, which results in melanistic Jaguars and other, more rare variations. The melanistic, or black, Jaguars are the most common variation, and are referred to as black panthers even though they are not a different species. White panthers are much more rare - the gene for albinism occurs much less frequently and is recessive, like the gene for melanism.
Female Jaguars will give birth to a litter of up to four cubs after a gestation period of 93 to 105 days. It's believed that Jaguars will mate year-round, and mating increases when food is plentiful. Female Jaguars will raise their cubs alone, rejecting the presence of any males after the cubs or born, due to the risk of male Jaguars killing the young cubs. The cubs will keep company with their mother, or at least remain in her territory, until they reach two years of age. At this point they will leave to establish their own territory.
The IUCN lists the Jaguar as Near Threatened due to the rapid decline in its population. Loss of habitat plays a large role in the threats facing the Jaguar, as well as poaching and persecution for being a perceived threat to livestock.