JAGUAR

 

The jaguar (Panthera onca) is a wild cat species and the only extant member of the genus Panthera native to the Americas. The jaguar’s present range extends from Southwestern United States and Mexico in North America, across much of Central America, and south to Paraguay and northern Argentina in South America. Though there are single cats now living within the Western United States, the species has largely been extirpated from the United States since the early 20th century. It is listed as Near Threatened on the IUCN Red List; and its numbers are declining. Threats include loss and fragmentation of habitat.

Overall, the jaguar is the largest native cat species of the New World and the third largest in the world. This spotted cat closely resembles the leopard, but is usually larger and sturdier. It ranges across a variety of forested and open terrains, but its preferred habitat is tropical and subtropical moist broadleaf forest, swamps and wooded regions. The jaguar enjoys swimming and is largely a solitary, opportunistic, stalk-and-ambush predator at the top of the food chain. As a keystone species it plays an important role in stabilizing ecosystems and regulating prey populations.

While international trade in jaguars or their body parts is prohibited, the cat is still frequently killed, 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.

In 1758, Carl Linnaeus described the jaguar in his work Systema Naturae and gave it the scientific name Felis onca. In the 19th and 20th centuries, several jaguar type specimens formed the basis for descriptions of subspecies. In 1939, Reginald Innes Pocock recognized eight subspecies based on geographic origins and skull morphology of these specimens. Pocock did not have access to sufficient zoological specimens to critically evaluate their subspecific status, but expressed doubt about the status of several. Later consideration of his work suggested only three subspecies should be recognized. The description of P. o. palustris was based on a fossil skull. The author of Mammal Species of the World listed nine subspecies and both P. o. palustris or P. o. paraguensis separately.

Results of morphologic and genetic research indicate a clinal north–south variation between populations, but no evidence for subspecific differentiation. A subsequent, more detailed study confirmed the predicted population structure within jaguar populations in Colombia.

The genus Panthera probably evolved in Asia between six and ten million years ago. The jaguar is thought to have diverged from a common ancestor of the Panthera at least 1.5 million years ago and to have entered the American continent in the Early Pleistocene via Beringia, the land bridge that once spanned the Bering Strait. Results of jaguar mitochondrial DNA analysis indicate that the species’ lineage evolved between 280,000 and 510,000 years ago. Its immediate ancestor was Panthera onca augusta, which was larger than the contemporary jaguar.

Phylogenetic studies generally have shown the clouded leopard (Neofelis nebulosa) is basal to this group.

Fossils of extinct Panthera species, such as the European jaguar (P. gombaszoegensis) and the American lion (P. atrox), show characteristics of both the jaguar and the lion (P. leo). Based on morphological evidence, the British zoologist Reginald Innes Pocock concluded that the jaguar is most closely related to the leopard (P. pardus). However, DNA-based evidence is inconclusive, and the position of the jaguar relative to the other species varies between studies.

The jaguar is a compact and well-muscled animal. It is the largest cat native to the Americas and the third largest in the world, exceeded in size by the tiger and lion. Its coat is generally a tawny yellow, but ranges to reddish-brown, for most of the body. The ventral areas are white. The fur is covered with rosettes for camouflage in the dappled light of its forest habitat. The spots and their shapes vary between individual jaguars: rosettes may include one or several dots. The spots on the head and neck are generally solid, as are those on the tail, where they may merge to form a band. Forest jaguars are frequently darker and considerably smaller than those in open areas, possibly due to the smaller numbers of large, herbivorous prey in forest areas.

Its size and weight vary considerably: weights are normally in the range of 56–96 kg (123–212 lb). Exceptionally big males have been recorded to weigh as much as 158 kg (348 lb). The smallest females weigh about 36 kg (79 lb). Females are typically 10–20 percent smaller than males. The length, from the nose to the base of the tail, varies from 1.12 to 1.85 m (3.7 to 6.1 ft). The tail is the shortest of any big cat, at 45 to 75 cm (18 to 30 in) in length. Legs are also short, but thick and powerful, considerably shorter when compared to a small tiger or lion in a similar weight range. The jaguar stands 63 to 76 cm (25 to 30 in) tall at the shoulders.

Further variations in size have been observed across regions and habitats, with size tending to increase from north to south. Mexican jaguars in the Chamela-Cuixmala Biosphere Reserve on the Pacific coast weighed just about 50 kg (110 lb), about the size of a female cougar. South American jaguars in Venezuela or Brazil are much larger with average weights of about 95 kg (209 lb) in males and of about 56–78 kg (123–172 lb) in females.

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 the third highest bite force of all felids, after the tiger and lion. A 100 kg (220 lb) jaguar can bite with a force of 503.6 kgf (1,110 lbf) at canine teeth and 705.8 kgf (1,556 lbf) at carnassial notch. This allows it to pierce the shells of armored reptiles and turtles. A comparative study of bite force adjusted for body size ranked it as the top field, alongside the clouded leopard and ahead of the tiger and lion. It has been reported that “an individual jaguar can drag an 800 lb (360 kg) bull 25 ft (7.6 m) in its jaws and pulverize the heaviest bones”.

While the jaguar closely resembles the leopard, it is generally 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.

At present, the jaguar’s range extends from Mexico through Central America to South America, including much of Amazonian Brazil. The countries included in this range are Argentina, Belize, Bolivia, Colombia, Costa Rica (particularly on the Osa Peninsula), Ecuador, French Guiana, Guatemala, Guyana, Honduras, Nicaragua, Panama, Paraguay, Peru, Suriname, the United States and Venezuela. It is now locally extinct in El Salvador and Uruguay.

It occurs in the 400 km² Cockscomb Basin Wildlife Sanctuary in Belize, the 5,300 km² Sian Ka’an Biosphere Reserve in Mexico, the approximately 15,000 km2 Man National Park in Peru, the approximately 26,000 km2 Xingu National Park in Brazil, and numerous other reserves throughout its range.

The inclusion of the United States in the list is based on occasional sightings in the southwest, particularly in Arizona, New Mexico and Texas. There are rock drawings made by the Hopi, Anasazi, and Pueblo all over the desert and chaparral regions. There are records of the beast being sold for its pelt in the vicinity of San Antonio, Texas for $18 apiece in the mid 19th century and there are records from well before California was a state that fit the description of this cat.

In the early 20th century, the jaguar’s range extended as far north as the Grand Canyon and possibly Colorado, and as far west as Monterey in Northern 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. Jaguar skins are also treated as illegal contraband by the US government and otherwise by and large Americans have stopped wearing fur coats made of the pelts of spotted cats as citizens are aware of the international plight of big cats. Unfortunately the cessation of hunting came too late to save the jaguar population from crashing and no kittens have been known to have been born on the other side of the Mexican-American border in generations.

In 1996 and from 2004 on, hunting guides and wildlife officials in Arizona photographed and documented jaguars in the southern part of the state. Between 2004 and 2007, two or three jaguars have been reported by researchers around Buenos Aires National Wildlife Refuge in southern Arizona. One of them, called ‘Macho B’, had been previously photographed in 1996 in the area. For any permanent population in the US to thrive, protection from killing, an adequate prey base, and connectivity with Mexican populations are essential. In February 2009, a 53.5 kg (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 there may be a permanent breeding population of jaguars within southern Arizona. The animal was later confirmed to be indeed the same male individual (‘Macho B’) that was photographed in 2004. On 2 March 2009, Macho B was recaptured and euthanized after he was found to be suffering from kidney failure; the animal was thought to be 16 years old, older than any known wild jaguar.

It is feared that completion of a United States–Mexico barrier may reduce the viability of any population currently residing in the United States, by reducing gene flow with Mexican populations, and may 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 km (620 mi) southward and its southern range 2,000 km (1,200 mi) 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 typically 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 Argentine 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 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. The jaguars preferred habitats are usually swamps and wooded regions, but jaguars also live in scrublands and deserts.

The adult jaguar is an apex predator, meaning it exists at the top of its food chain and is not preyed on in the wild. The jaguar has also been termed a keystone species, as it is assumed, through controlling the population levels of prey such as herbivorous and granivorous mammals, apex felids maintain the structural integrity of forest systems. However, accurately determining what effect species like the jaguar have on ecosystems is difficult, because data must be compared from regions where the species is absent as well as its current habitats, while controlling for the effects of human activity. It is accepted that mid-sized prey species undergo population increases in the absence of the keystone predators, and this has been hypothesized to have cascading negative effects. However, field work has shown this may be natural variability and the population increases may not be sustained. Thus, the keystone predator hypothesis is not accepted by all scientists.

The jaguar also has an effect on other predators. The jaguar and the cougar, which is the next-largest feline of South America, but the biggest in Central or North America, are often sympatric (related species sharing overlapping territory) and have often been studied in conjunction. The jaguar tends to take larger prey, usually over 22 kg (49 lb) and the cougar smaller, usually between 2 and 22 kg (4.4 and 48.5 lb), 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. Depending on the availability of prey, the cougar and jaguar may even share it.

aguar females reach sexual maturity at about two years of age, and males at three or four. The cat probably mates throughout the year in the wild, with births increasing when prey is plentiful. Research on captive male jaguars supports the year-round mating hypothesis, with no seasonal variation in semen traits and ejaculatory quality; low reproductive success has also been observed in captivity.

Generation length of the jaguar is 9.8 years.

Female estrus is 6–17 days out of a full 37-day cycle, and females will advertise fertility with urinary scent marks and increased vocalization. Females range more widely than usual during courtship. Pairs separate after mating, 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 infanticide; 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 all cats, the jaguar is an obligate carnivore, feeding only on meat. It is an opportunistic hunter and its diet encompasses at least 87 species. The jaguar can take virtually any terrestrial or riparian vertebrate found in Central or South America, except for large crocodilians such as black caiman. Jaguars are excellent swimmers and will dive under the water to catch turtles in rivers and the occasional fish. The jaguar is more of a dietary generalist than its Old World cousins: the American tropics have a high diversity of small animals but relatively low populations and diversity of the large ungulates which this genus favors. They regularly take adult caimans, except for black caimans, deer, capybaras, tapirs, peccaries, dogs, zorros, and sometimes even anacondas. However, it preys on any small species available, including frogs, mice, birds (mainly ground-based species such as cracids), fish, sloths, monkeys, and turtles. A study conducted in Cockscomb Basin Wildlife Sanctuary in Belize revealed that the diet of jaguars there consisted primarily of armadillos and pacas. Some jaguars will also take domestic livestock. El Jefe, one of the few jaguars that were reported in the United States, has also been found to kill and eat American black bears, as deduced from hairs found within his scats and the partly consumed carcass of a black bear sow with the distinctive puncture marks to the skull left by jaguars. This indicates that jaguars might have once preyed on black bears when the species was still present in the area. Spectacled bears are also known to avoid jaguars, possibly because they may constitute occasional prey items.

While the jaguar often employs the deep throat-bite and suffocation technique typical among Panthera, it sometimes uses a killing method unique among 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, armored 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 the caiman, the jaguar may leap onto the back of the prey and sever the cervical vertebrae, immobilizing the target. When attacking sea turtles, including the huge leatherback sea turtle which weighs about 385 kg (849 lb) on average, as they try to nest on beaches, the jaguar will bite at the head, often beheading the prey, before dragging it off to eat. Reportedly, while hunting horses, a jaguar may leap onto their back, place one paw on the muzzle and another on the nape and then twist, dislocating the neck. Local people have anecdotally reported that when hunting a pair of horses bound together, the jaguar will kill one horse and then drag it while the other horse, still living, is dragged in their wake. v With prey such as smaller dogs, a paw swipe to the skull may be sufficient to kill it.

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 kg (75 lb) animal, at the extreme low end of the species’ weight range, has been estimated at 1.4 kg (3.1 lb). For captive animals in the 50–60 kg (110–130 lb) range, more than 2 kg (4.4 lb) of meat daily are recommended. In the wild, consumption is naturally more erratic; wild cats expend considerable energy in the capture and kill of prey, and they may consume up to 25 kg (55 lb) of meat at one feeding, followed by periods of famine. Though carnivorous, there is evidence that jaguars in the wild consume the roots of Banisteriopsis caapi.

Jaguar populations are rapidly declining. The species is listed as Near Threatened on the IUCN Red List. The loss of parts of its range, including its virtual elimination from its historic northern areas and the increasing fragmentation of the remaining range, have contributed to this status. Particularly significant declines occurred in the 1960s, when more than 15,000 jaguars were killed for their skins in the Brazilian Amazon yearly; the Convention on International Trade in Endangered Species of 1973 brought about a sharp decline in the pelt trade. Detailed work performed under the auspices of the Wildlife Conservation Society revealed the species has lost 37% of its historic range, with its status unknown in an additional 18% of the global range. More encouragingly, the probability of long-term survival was considered high in 70% of its remaining range, particularly in the Amazon basin and the adjoining Gran Chaco and Pantanal.

The major risks to the jaguar include deforestation across its habitat, increasing competition for food with human beings, especially in dry and unproductive habitat, 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 jaguar 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.

The skins of wild cats and other mammals have been highly valued by the fur trade for many decades. From the beginning of the 20th-century Jaguars were hunted in large numbers, but over-harvest and habitat destruction reduced the availability and induced hunters and traders to gradually shift to smaller species by the 1960s. The international trade of jaguar skins had its largest boom between the end of the Second World War and the early 1970, due to the growing economy and lack of regulations. From 1967 onwards, the regulations introduced by national laws and international agreements diminished the reported international trade from as high as 13000 skins in 1967, through 7000 skins in 1969, until it became negligible after 1976, although illegal trade and smuggling continue to be a problem. During this period, the biggest exporters were Brazil and Paraguay, and the biggest importers were the US and Germany.