Jaguar (animal) - biology.

Jaguar (animal) - biology. I INTRODUCTION Jaguar (animal), muscular, stocky member of the cat family found primarily in Central and South America. It is the third largest of the world's cats and the largest and most powerful cat in the Americas. Jaguars are known as el tigre throughout most of South America and onca in Brazil. The name jaguar is derived from yaguara, a word from an indigenous South American language that means "wild beast that overcomes its prey with a single bound." The jaguar's image has dominated the culture and mythology of Central and South America, where the jaguar is a symbol of power, closely associated with thunder, lightning, and rain. Jaguar sculptures have been discovered in Peru among the artifacts of the earliest known civilization in South America. In Mexico 2,000 years ago the Olmec people paid homage to the jaguar with 20-ton jaguar statues and giant pavement mosaics. Today, some indigenous peoples still engage in ceremonies that celebrate the jaguar before they partake in important hunting expeditions. Among the 36 cat species, jaguars are most closely related to lions, leopards, and tigers. These four big cats evolved from a common ancestor about 2 million to 3 million years ago. Recent genetic studies suggest that jaguars and leopards may be the most closely related members of the big cats. Physically, jaguars and leopards look quite similar, but compared side-by-side the jaguar is heavier and more powerful looking, with a much larger head than the leopard. II RANGE AND HABITAT Today the jaguar ranges from Mexico through much of South America, including Colombia, Venezuela, Suriname, Brazil, Peru, Paraguay, and northern Argentina. Until quite recently, jaguars also survived further north in Arizona, New Mexico, Colorado, and Texas. Two of the last remaining jaguars in North America were shot in Texas in 1946 and in Arizona in 1949. However, the species may be making a comeback into its North American range. In 1996 a mountain lion hunter photographed a young male jaguar in southeastern Arizona and, in 2001 and again in 2003, a remote surveillance camera photographed a jaguar on the Arizona-Mexico border. Jaguars usually live in dense tropical forest, preferring wetter areas near streams and rivers, or in swampy grasslands. Jaguars enjoy water--they are great swimmers, capable of crossing even the widest rivers. They often spend the heat of the day half-submerged in a stream or pool. However, these cats can also survive in such drier habitats as dry forests and scrub, and they sometimes travel along wooded riverbeds into semidesert areas. Jaguars are good climbers and often rest in trees. III PHYSICAL DESCRIPTION More than any of the other big cats, jaguars convey an image of muscular power. They have a strong, stocky body, a deep chest, and short, sturdy legs that make them appear larger than they really are. Jaguars have a massive, almost oversized head, and their robust, well-developed canine teeth can deliver a bite that is more powerful than that of other big cats. The jaguar's ears are short and rounded with a faint pale spot on the back. The large eyes are golden reddish-brown with a round pupil. Jaguars vary tremendously in size and males are usually 20 to 30 percent larger and heavier than females. The largest jaguars are found in the seasonally flooded grasslands of Brazil and Venezuela, where males average 102 kg (224 lb) and females average 72 kg (158 lb). An exceptionally large male killed in Venezuela weighed 147 kg (325 lb). Jaguars in Central America and southern Mexico are about half this size. In this area males average 56 kg (123 lb) and females about 40 kg (90 lb)--not much heavier than a large golden retriever. The jaguar's tawny yellow fur is marked with large clusters of dark spots and irregularly shaped blotches. The largest blotches resemble paw prints and often have one or two black dots in the center. Smaller solid spots dot the head, neck, and legs, and the tail is marked with black spots that merge to form bands near the tip. The background coat color and markings vary greatly from cat to cat. Just as with human fingerprints, individual jaguars can be identified by their markings. All-black, or melanistic, jaguars are fairly common, especially in South America where roughly 1 in 16 jaguars is black. In these individuals the spot pattern is usually visible beneath the dark coat color. Jaguars use their strong curved claws for grasping and holding prey. The front feet have five toes, but only four of the toes leave footprints because the fifth toe pad is higher up on the foreleg and clear of the ground. There are four toes on the hind foot. Males have larger feet than females. Captive jaguars have survived 25 years. It is not known how long wild jaguars live, but it is unlikely that many survive longer than 12 to 15 years. IV SOCIAL BEHAVIOR Of all the big cats, jaguars are the most elusive and least studied. Jaguars travel and hunt alone. The occasional sightings of two or more animals together are usually a mother and her cubs or a courting pair. Both males and females have individual home ranges--areas where they live and hunt. Male home ranges are larger than female home ranges. Female ranges often overlap with those of other jaguars, but neighbors tend to avoid using the same area at the same time. Jaguars mark their home range by spraying urine on trees and prominent objects and by leaving scrape marks and feces along a path. They also sharpen their claws on trees. In addition, both male and female jaguars roar to broadcast their presence and warn other jaguars to stay away. The jaguar roar resembles a series of short hoarse coughs--UH, UH, UH, uh, uh. The call grows faster and louder, then fades away. V DIET AND HUNTING The diet of jaguars reflects the variety and abundance of prey in the areas where they live. In the flooded grasslands of Brazil and Venezuela, jaguars feed on capybara, caiman, turtles, peccary, deer, and cattle. In the lowland tropical rain forest of Peru, they hunt anteaters, monkeys, and agouti. Jaguars also feed on fish. In the wetlands of Venezuela and Brazil large catfish breed in shallow ponds and lagoons. At the end of the dry season the ponds dry up, leaving the fish vulnerable to all kinds of predators, including jaguars. Jaguars are capable of killing just about any type of prey they encounter. They can kill animals ranging in size from an armadillo that weighs 1 kg (2 lb) to a cow that weighs more than 450 kg (1,000 lb). Jaguars hunt by walking slowly along trails, watching and listening for prey. They also wait in ambush beside trails and will leap into the water in pursuit of prey. They hunt when their prey is most active. In areas where they feed on nocturnal prey, they hunt at night. Jaguars preying on cattle often hunt during the daytime, and they usually kill caiman and turtles while these reptiles bask beside the water during the day. Jaguars have an unusual method of killing large prey. Whereas lions, tigers, and leopards kill with a throat or neck bite, jaguars often kill large prey by biting through the skull between the ears. Jaguars also use their powerful jaws and strong canine teeth to break open the heavy shells of large river turtles. Empty broken turtle shells with traces of jaguar hair around the openings are often found on favorite turtle-nesting beaches. No other big cat regularly hunts turtles and caimans, and some scientists have speculated that the jaguar's robust canine teeth and enormously powerful bite developed specifically to pierce the armor of these reptiles. After killing a large animal, a jaguar will usually drag the carcass into dense cover before beginning to eat. If the kill is made in an open area, jaguars often drag their prey for considerable distances. On one occasion, a jaguar killed a cow on the edge of a river and swam 790 m (2,600 ft) across the river carrying the cow. Unlike the other big cats, which usually begin feeding at a large prey's hindquarters, jaguars start to eat at the head and neck, then move to the shoulders. They spend about 2 to 3 days with a kill and often abandon a carcass leaving the hindquarters untouched. VI REPRODUCTION Female jaguars become able to breed when they are about 2y years old. In the wild, where males have to compete for females, the largest and strongest male dominates the breeding. So males usually do not mate until they are 3 or 4 years old. In captivity, when males do not have to compete for females, male jaguars may begin to breed when they are only two years of age. In most tropical parts of their range, jaguars breed all year round. But in Argentina and Mexico, where there are noticeable seasons, most births occur when prey is plentiful. After a gestation period (pregnancy) of about 100 days, the female gives birth in a secluded den in a cave, beneath a fallen tree, or in dense vegetation. Females usually give birth to two cubs, but on rare occasions a female may deliver as many as four cubs. The female raises the cubs without help from the male. Cubs weigh about 1 kg (2 lbs) when they are born. Their pale-buff colored fur is coarse and woolly, marked with distinct black spots. The cub's eyes open after 3 to 13 days. Young jaguars begin to eat meat when they are around 10 to 11 weeks old. Even though they are eating solid food, cubs continue to nurse until they are five or six months old. They stay with their mother until they are about 1y to 2 years of age and during this time they gradually learn to hunt for themselves. When the young jaguars are ready to separate from their mother, they disperse in search of their own home range. Young females sometime stay on and share a portion of their mother's home range, but young males usually leave their birth area and travel long distances in search of a place to settle. VII CONSERVATION STATUS During the 1950s and 1960s thousands of jaguars were killed each year for the fur trade. In the 1960s nearly 15,000 jaguar skins were imported each year into the United States and Europe. During that time, high-quality jaguar coats were sold in New York for as much as $20,000. The 1975 Convention of International Trade in Endangered Species (CITES) treaty prohibited international trade in most wild cats and was dramatically effective in curtailing trade of jaguar skins. By 1990 international trade in jaguar skins had fallen to zero. However, the jaguar still faces other human threats. In areas where jaguars roam, much forest has been converted to farms and cattle ranches. Poaching, habitat loss, and competition with subsistence hunters for prey threaten the jaguar throughout its range. As more and more forest is converted to cattle ranches, jaguars prey on cattle with more frequency. As a result, ranchers actively hunt jaguars to protect their livestock. Conservation groups are working to find ways to minimize jaguar predation on livestock and build local support for conservation. Scientific classification: The jaguar belongs to the family Felidae. It is classified as Panthera onca. Contributed By: Melvin E. Sunquist Fiona C. Sunquist Microsoft ® Encarta ® 2009. © 1993-2008 Microsoft Corporation. All rights reserved.