Interesting Creatures… The Jaguar

Aug 14, 2011 Features / Columnists, Interesting Creatures in Guyana

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The jaguar 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 Southern US and Mexico across much of Central America and south to Paraguay and northern Argentina.
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 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 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 is a near threatened species and its numbers are declining. Threats include habitat loss and fragmentation. 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.

PHYSICAL CHARACTERISTICS
The size of jaguars tends to increase the farther south they are located.The jaguar is a compact and well-muscled animal. There are significant variations in size and weight: weights are normally in the range of 56–96 kilograms (124–211 lb). Larger males have been recorded at 160 kilograms (350 lb)[27] (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 metres (5.3–6 ft), 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 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 pounds-force (8,900 N). This is twice the strength of a lion and the second strongest of all mammals after the spotted hyena; 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 field, 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.
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.

REPRODUCTION AND LIFE CYCLE
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.[37] 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 infanticide; this behaviour 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.

SOCIAL ACTIVITY
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, which range 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. The jaguar uses scrape marks, urine, and feces to mark its 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 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
Like all cats, the jaguar is an obligate carnivore, feeding only on meat. It is an opportunistic hunter and its diet encompasses 87 species. The jaguar prefers large prey and will take adult caiman (a form of small alligator), deer, capybara, tapirs, peccaries, dogs, foxes, and sometimes even anacondas.
However, the cat will eat any small species that can be caught, including frogs, mice, birds, fish, sloths, monkeys, and turtles. Some jaguars will also take domestic livestock, including adult cattle and horses.
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.[

DISTRIBUTION AND HABITAT
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 (particularly on the Osa Peninsula), Ecuador, French Guiana, Guatemala, Guyana, Honduras, Mexico, Nicaragua, Panama, Paraguay, Peru, Suriname, United States and Venezuela. The jaguar is now extinct in El Salvador and Uruguay.
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 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 3,800 m, but they typically avoid montane forest and are not found in the high plateau of central Mexico or in the Andes.

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