The etymology of the word jaguar is unclear. Some sources
suggest a borrowing from the South American Tupi language to
English via Portuguese, while others attribute the term to the
related Guaraní languages. In the Tupi language, the original
and complete indigenous name for the species is jaguara, which
has been reported as a denotation for any carnivorous animal—in
the compound form jaguareté, -eté means "true". In the related
Guaraní languages, yaguareté has been variously translated as
"the real fierce beast", "dog-bodied", or "fierce dog". Early
etymological reports were that jaguara means "a beast that kills
its prey with one bound," and this claim persists in a number of
sources. However, this has been challenged as incorrect. In many
Central and South American countries, the cat is referred to as
el tigre ("the tiger").
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.
The jaguar, Panthera onca, is the only New World member of the Panthera genus. DNA evidence shows that the lion, the tiger, the leopard, the jaguar, the snow leopard and the 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. The clouded leopard (Neofelis nebulosa) is generally placed at the basis of this group. The position of the remaining species varies between studies and is effectively unresolved. Many studies place the snow leopard within the genus Panthera but there is no consensus whether the scientific name of the snow leopard should remain Uncia uncia or be moved to Panthera uncia.
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.
The last taxonomic delineation of the jaguar subspecies was performed by Pocock in 1939. Based on geographic origins and skull morphology, he recognized 8 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 3 subspecies should be recognized.
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.
The jaguar is a compact and well-muscled animal. There are
significant variations in size: weights are normally in the
range of 56–96 kilograms (124–211 lb). Larger animals have been
recorded as weighing 131–151 kilograms (288–333 lb) (roughly
matching a tigress or lioness), and smaller ones have extremely
low weights of 36 kilograms (80 lb). Females are typically
10–20% smaller than males. The length of the cat varies from
1.62–1.83 meters (5.3–6 feet), and its tail may add a further 75
centimeters (30 in). It stands about 67–76 centimeters (27–30
in) tall at the shoulders.
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.
Jaguar females reach sexual maturity at about two years of age, and males at three or four. The cat is believed to mate throughout the year in the wild, although births may increase 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. Female estrous is 6–17 days out of a full 37-day cycle, and females will advertise fertility with urinary scent marks and increased vocalization. Both sexes will range more widely than usual during courtship.
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 most cats, the jaguar is solitary outside mother-cub groups. Adults generally meet only to court and mate (though limited non-courting socialization has been observed anecdotally) and carve out large territories for themselves. Female territories, from 25 to 40 square kilometers in size, may overlap, but the animals generally avoid one another. Male ranges cover roughly twice as much area, varying in size with the availability of game and space, and do not overlap. Scrape marks, urine, and feces are used to mark territory.
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 behaviour has been observed in the wild. When it occurs, conflict is typically over territory: a male's range 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 dusk). Both sexes hunt, but males travel further 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.
Like all cats, the jaguar is an obligate carnivore, feeding only on meat. It is an opportunistic hunter and its diet encompasses 85 species. The jaguar prefers large prey and will take deer, tapirs, peccaries, dogs, and even anacondas and caiman. However, the cat will eat any small species that can be caught, including frogs, mice, birds, fish, sloths, monkeys, turtles, capybara, and domestic livestock.
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, 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 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.
The jaguar has been attested in the fossil record for two million years and it has been an American cat since crossing the Bering Land Bridge during the Pleistocene; the immediate ancestor of modern animals is Panthera onca augusta, which was larger than the contemporary cat. Its present range extends from Mexico, through Central America and into South America, including much of Amazonian Brazil. The countries included in this range are Argentina, Belize, Bolivia, Brazil, Colombia, Costa Rica, Ecuador, French Guiana, Guatemala, Guyana, Honduras, Mexico, Nicaragua, Panama, Paraguay, Peru, Suriname, U.S. and Venezuela. The jaguar is now extinct in El Salvador and Uruguay. The largest protected jaguar habitat is the 400 square kilometer Cockscomb Basin Wildlife Sanctuary in Belize.
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 kya, 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 Argentinian 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.
A jaguar in a wildlife rescue & rehabilitation centre in Argentina.The jaguar is an apex predator, meaning that it exists at the top of its food chain and is not regularly 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 see population increases in the absence of the keystone predators and it has been hypothesized that this has cascading negative effects, however, field work has shown this may be natural variability and that the population increases may not be sustained. Thus, the keystone predator hypothesis is not favoured by all scientists.
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.
This Jaguar Page is Copyright The Animal Web Guide © 2004 - 2009 Chuck Ayoub