|The Jaguar (Panthera onca) is a New World mammal of the Felidae family and one of four "big cats" in the Panthera genus, along with the tiger, the lion and the leopard of the Old World. The jaguar is the third-largest feline after the tiger and the lion, and on average the largest and most powerful feline in the Western Hemisphere. The jaguar's present range extends from Mexico (with occasional sightings in the southwestern United States) across much of Central America and south to Paraguay and northern Argentina.
This spotted cat most closely resembles the leopard physically, although it is 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 terrain. 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 a largely solitary, stalk-and-ambush predator, and is opportunistic in prey selection. It is also an apex and keystone predator, playing an important role in stabilizing ecosystems and regulating the populations of prey species. The jaguar has developed 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 blow to the brain.
The first component of its scientific designation, Panthera onca, is often presumed to derive from Greek pan- ("all") and ther ("beast"), but this may be a folk etymology. Although it came into English through the classical languages, panthera is probably of East Asian origin, meaning "the yellowish animal," or "whitish-yellow".
Onca is said to denote "barb" or "hook", a reference to the animal's powerful claws, but the most correct etymology is simply that it is an adaptation of the current Portuguese name for the animal, onça (on-sa), with the cedilla dropped for typographical reasons.
Based on morphological evidence, British zoologist Reginald Pocock concluded that 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.
Recent studies have also failed to find evidence for well defined subspecies, and are no longer recognized. Larson (1997) studied the morphological variation in the jaguar and showed that there is clinal north - south variation, but also that 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. Seymore grouped these in three subspecies.
The canonical Mammal Species of the World continues to recognize nine subspecies, the eight subspecies above and additionally P. o. paraguensis.
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 30 - 50 kilograms (66 - 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 kilograms (220 lb). 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 fewer 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. It has been suggested that the jaguar has the strongest bite of all felids, and the second strongest of all mammals; this strength is an adaptation that 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 kilograms (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. The cat is covered in rosettes for camouflage in its jungle habitat. The spots vary over individual coats and between individual Jaguars: rosettes may include one or several dots, and the shape of the dots varies. The spots on the head and neck are generally solid, as are those on the tail, where they may merge to form a band. The underbelly, throat and outer surface of the legs and lower flanks are white.
A condition known as melanism occurs in the species. The melanistic form is less common than the spotted form-six percent of jaguars in their South American range have been reported to possess it-and is the result of a dominant allele. Jaguars with melanism appear entirely black, although their spots are still visible on close examination. Melanistic Jaguars are informally known as black panthers, but do not form a separate species. Rare albino individuals, sometimes called white panthers, occur among jaguars, as with the other big cats.
The jaguar closely resembles the leopard, but 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.
Reproduction and life cycle
Mating pairs separate after the act, and females provide all parenting. The gestation period lasts 93 - 105 days; females give birth to up to four cubs, and most commonly to two. The mother will not tolerate the presence of males after the birth of cubs, given a risk of infant cannibalism; this behavior is also found in the tiger.
The young are born blind, gaining sight after two weeks. Cubs are weaned at three months but remain in the birth den for six months before leaving to accompany their mother on hunts. They will continue in their mother's company for one to two years before leaving to establish a territory for themselves. Young males are at first nomadic, jostling with their older counterparts until they succeed in claiming a territory. Typical lifespan in the wild is estimated at around 12 - 15 years; in captivity, the jaguar lives up to 23 years, placing it among the longest-lived cats.
Like the other big cats, the jaguar is capable of roaring (the male more powerfully) and does so to warn territorial and mating competitors away; intensive bouts of counter-calling between individuals have been observed in the wild. Their roar often resembles a repetitive cough, and they may also vocalize mews and grunts. Mating fights between males occur, but are rare, and aggression avoidance behavior has been observed in the wild. When it occurs, conflict is typically over territory: a male's ange may encompass that of two or three females, and he will not tolerate intrusions by other adult males.
The jaguar is often described as nocturnal, but is more specifically crepuscular (peak activity around dawn and duk). Both sexes hunt, but males travel farther each day than females, befitting their larger territories. The jaguar may hunt during the day if game is available and is a relatively energetic feline, spending as much as 50 - 60% of its time active. The jaguar's elusive nature and the inaccessibility of much of its preferred habitat make it a difficult animal to sight, let alone study.
Hunting and diet
While the jaguar employs the deep-throat bite-and-suffocation technique typical among Panthera, it prefers a killing method unique amongst cats: it pierces directly through the temporal bones of the skull between the ears of prey (especially the Capybara) with its canine teeth, piercing the brain. This may be an adaptation to "cracking open" turtle shells; following the late Pleistocene extinctions, armoured reptiles such as turtles would have formed an abundant prey base for the jaguar. The skull bite is employed with mammals in particular; with reptiles such as caiman, the jaguar may leap on to the back of the prey and sever the cervical vertebrae, immobilizing the target. While capable of cracking turtle shells, the jaguar may simply reach into the shell and scoop out the flesh. With prey such as dogs, a paw swipe to crush the skull may be sufficient.
The jaguar is a stalk-and-ambush rather than a chase predator. The cat will walk slowly down forest paths, listening for and stalking prey before rushing or ambushing. The jaguar attacks from cover and usually from a target's blind spot with a quick pounce; the species' ambushing abilities are considered nearly peerless in the animal kingdom by both indigenous people and field researchers, and are probably a product of its role as an apex predator in several different environments. The ambush may include leaping into water after prey, as a jaguar is quite capable of carrying a large kill while swimming; its strength is such that carcasses as large as a heifer can be hauled up a tree to avoid flood levels.
On killing prey, the jaguar will drag the carcass to a thicket or other secluded spot. It begins eating at the neck and chest, rather than the midsection. The heart and lungs are consumed, followed by the shoulders. The daily food requirement of a 34 kilogram animal, at the extreme low end of the species' weight range, has been estimated at 1.4 kilograms. For captive animals in the 50 - 60 kilogram range, more than 2 kilograms of meat daily is recommended. In the wild, consumption is naturally more erratic; wild cats expend considerable energy in the capture and kill of prey, and may consume up to 25 kilograms of meat at one feeding, followed by periods of famine.
Distribution and habitat
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 1900s, the jaguar's range extended as far north as Southern California and western Texas. 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 south of the state. For any permanent population to thrive in Arizona, protection from killing, an adequate prey base, and connectivity with Mexican populations are essential.
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 1000 kilometers southward and its southern range 2000 km northward. Ice Age fossils of the jaguar, dated between 40,000 and 11,500 annum 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 Argentinean 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 3800 m, but they typically avoid mountain forest and are not found in the high plateau of central Mexico or in the Andes.
The jaguar also has an effect on other predators. The jaguar and the cougar, the next largest feline of the Americas, are often sympatric (related species sharing overlapping territory) and have often been studied in conjunction. Where sympatric with the jaguar, the cougar is smaller than normal. The jaguar tends to take larger prey and the cougar smaller, reducing the latter's size. This situation may be advantageous to the cougar. Its broader prey niche, including its ability to take smaller prey, may give it an advantage over the jaguar in human-altered landscapes; while both are classified as near-threatened species, the cougar has a significantly larger current distribution.
The major risks to the jaguar include deforestation across its habitat, increasing competition for food with human beings, poaching, hurricanes in Northern parts of its range, and the behavior of ranchers who will often kill the cat where it preys on livestock. When adapted to the prey, the jaguars has been shown to take cattle as a large portion of its diet; while land clearance for grazing is a problem for the species, the jaguar population may have increased when cattle were first introduced to South America as the animals took advantage of the new prey base. This willingness to take livestock has induced ranch owners to hire full-time jaguar hunters, and the cat is often shot on sight.
The jaguar is regulated as an Appendix I species under CITES: all international trade in jaguars or their parts is prohibited. All hunting of jaguars is prohibited in Argentina, Belize, Colombia, French Guiana, Honduras, Nicaragua, Panama, Paraguay, Suriname, the United States (where it is listed as endangered under the Endangered Species Act), Uruguay and Venezuela. Hunting of jaguars is restricted to "problem animals" in Brazil, Costa Rica, Guatemala, Mexico and Peru, while trophy hunting is still permitted in Bolivia. The species has no legal protection in Ecuador or Guyana.
Current conservation efforts often focus on educating ranch owners and promoting ecotourism. The jaguar is generally defined as an "umbrella species"-a species whose home range and habitat requirements are sufficiently broad that, if protected, numerous other species of smaller range will also be protected. Umbrella species serve as "mobile links" at the landscape scale, in the jaguar's case through predation. Conservation organizations may thus focus on providing viable, connected habitat for the jaguar, with the knowledge that other species will also benefit.
Given the inaccessibility of much of the species' range-particularly the central Amazon-estimating jaguar numbers is difficult. Researchers typically focus on particular bioregions, and thus species-wide analysis is scant. In 1991, 600 - 1,000 (the highest total) were estimated to be living in Belize. A year earlier, 125 - 180 jaguars were estimated to be living in Mexico's 4,000 square kilometer (2400 mi²) Calakmul Biosphere Reserve, with another 350 in the state of Chiapas. The adjoining Maya Biosphere Reserve in Guatemala, with an area measuring 15,000 square kilometers (9,000 mi²), may have 465 - 550 animals. Work employing GPS-telemetry in 2003 and 2004 found densities of only six to seven jaguars per 100 square kilometers in the critical Pantanal region, compared with 10 to 11 using traditional methods; this suggests that widely used sampling methods may inflate the actual numbers of cats.
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