Wild Animals Pictures BiographyThe black jaguar is one of three animals called "panther" – the others are the black leopard and the cougar.
Temporal range: Early to Middle Pleistocene – Recent
The jaguar (/ˈdʒæɡwɑr/ or UK /ˈdʒæɡjuː.ər/), Panthera onca, is a big cat, a feline in the Panthera genus, and is the only Panthera species found in the Americas. The jaguar is the third-largest feline after the tiger and the lion, and the largest in the Western Hemisphere. 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), 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 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- "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, Uncia 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. 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.
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.
While numerous subspecies of the jaguar have been recognized, 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 recognized.
Recent studies have also failed to find evidence for well-defined subspecies, which are no longer recognized. 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.
Biology and behavior
The head of the jaguar is robust and the jaw extremely powerful. The size of jaguars tends to increase the farther south they are located.
The jaguar, a compact and well-muscled animal, is the largest cat in the New World and the largest carnivorous mammal in Central and South America. Size and weight vary considerably: weights are normally in the range of 56–96 kg (124–211 lb). Larger males have been recorded to weigh as much as 160 kg (350 lb) (roughly matching a tigress or lioness), and the smallest females have low weights of 36 kg (79 lb). Females are typically 10–20% smaller than males. The length, from the nose to the base of the tail, of the cats varies from 1.2 to 1.95 m (3.9 to 6.4 ft). Their tails are the shortest of any big cat, at 45 to 75 cm (18 to 30 in) in length. Their legs are also short, considerably shorter when compared to a small tiger or lion in a similar weight range, but are thick and powerful. The jaguar stands 63 to 76 cm (25 to 30 in) tall at the shoulders. Compared to the similarly colored Old World leopard, this cat is bigger, heavier and relatively stocky in build.
Further variations in size have been observed across regions and habitats, with size tending to increase from the north to south. A study of the jaguar in the Chamela-Cuixmala Biosphere Reserve on the Mexican Pacific coast, showed ranges of just about 50 kg (110 lb), about the size of the cougar. By contrast, a study of the jaguar in the Brazilian Pantanal region found average weights of 100 kg (220 lb), and weights of 136 kilograms (300 lb) or more are not uncommon in old males. Forest jaguars are frequently darker and considerably smaller than those found in open areas (the Pantanal is an open wetland basin), possibly due to the smaller numbers of large, herbivorous prey in forest areas.
A short and stocky limb structure makes the jaguar adept at climbing, crawling, and swimming. The head is robust and the jaw extremely powerful. The jaguar has the strongest bite of all felids, capable of biting down with 2,000 lbf (910 kgf). This is twice the strength of a lion and the second strongest of all mammals after the spotted hyena; this strength adaptation allows the jaguar to pierce turtle shells. A comparative study of bite force adjusted for body size ranked it as the top felid, alongside the clouded leopard and ahead of the lion and tiger. It has been reported that "an individual jaguar can drag a 360 kg (800 lb) bull 8 m (25 ft) in its jaws and pulverize the heaviest bones". The jaguar hunts wild animals weighing up to 300 kg (660 lb) in dense jungle, and its short and sturdy physique is thus an adaptation to its prey and environment. The base coat of the jaguar is generally a tawny yellow, but can range to reddish-brown and black, for most of the body. However, the ventral areas are white. The cat is covered in rosettes for camouflage in the dappled light of its forest habitat. The spots vary over individual coats and between individual jaguars: rosettes may include one or several dots, and the shapes of the dots vary. The spots on the head and neck are generally solid, as are those on the tail, where they may merge to form a band.
While the jaguar closely resembles the leopard, it is sturdier and heavier, and the two animals can be distinguished by their rosettes: the rosettes on a jaguar's coat are larger, fewer in number, usually darker, and have thicker lines and small spots in the middle that the leopard lacks. Jaguars also have rounder heads and shorter, stockier limbs compared to leopards.
A melanistic jaguar is a color morph which occurs at about 6% frequency in populations.
Color morphism occurs in the species. A near-black melanistic form occurs regularly. Jaguars with melanism appear entirely black, although their spots are still visible on close examination.
The black morph is less common than the spotted form but, at about six percent of the population, it is several orders of magnitude above the rate of mutation. Hence, it is being supported by selection. Some evidence indicates the melanism allele is dominant. The black form may be an example of heterozygote advantage; breeding in captivity is not yet conclusive on this.
Melanistic jaguars are informally known as black panthers, but (as with all forms of polymorphism) they do not form a separate species.
Extremely rare albino individuals, sometimes called white panthers, also occur among jaguars, as with the other big cats. As usual with albinos in the wild, selection keeps the frequency close to the rate of mutation.