Keystone Species - Vital To Ecosystems

The Jaguar

The jaguar belongs to the Panthera genus. There are four species in the genus:

  • the lion (Panthera leo)
  • the tiger (Panthera tigris)
  • the leopard (Panthera pardis) and
  • the jaguar (Panthera onca).

While 'panther' technically refers to all members of the genus, the term is usually reserved for the black panther, a melanistic colour variation of the leopard, jaguar or cougar, depending on the region where the term is used.

The Panthera genus is the only genus with the capacity to roar. While this was once thought to be because of incomplete ossification of the hyoid bone, it is actually due to special morphology of the larynx.

The jaguar is at the top of the food chain so is an apex predator. It is also a keystone species, one of those organisms which have a major role in maintaining the status quo of an ecosystem. It feeds on a vast range of prey and regulates the populations of these native animals, creating a balanced environment. Should a keystone species disappear, the ecosystem changes drastically and could result in disastrous consequences. Other keystone species include the mountain tapir, cassowary and prairie dog.

Taxonomic classification of the panther varies from source to source with up to eight subspecies being recognised by some. Because of its shyness and the inaccessibility of its preferred habitat, the jaguar has been difficult to research.

Distribution Map(81511)Credit: By Jürgen at nl.wikipedia [GFDL (, CC-BY-SA-3.0 ( or CC-BY-SA-2.5 (], from Wikimedia Commons

At the moment, the jaguar is found from the southern USA, (particularly Arizona, New Mexico and Texas), through Mexico, much of Central America and south to Paraguay and northern Argentina. Although there is a small population in Arizona, the jaguar is now largely absent from the rest of the USA.

There is substantial evidence to suggest that a colony of feral leopards or jaguars inhabit the rainforests around Sydney, Australia. There are over 450 recorded reports of sightings but capture has so far proved impossible. In Nannup, Western Australia, the locals are equally sure that some non-native animal is at large in the area. Unusual animal screams at night and the behaviour of local dogs at such times have led to talk of a 'Nannup tiger' frequenting the area.

The jaguar has a preference for dense rainforest but is found across a variety of forested and open terrain. Like the tiger, it enjoys the water and will seek out waterways such as swamps and rivers.

The jaguar is compact and muscular. There is sizeable variations in size and weight. The jaguar tends to increase in size to the south of its range. Weights vary from 56 to 96 kg and even up to 160 kg. Females are generally 10 to 20% smaller. It is around 63 to 76 cm tall at the shoulders and 1.2 to 1.95 metres long with the addition of another 45 to 75 cm for the tail.

Being short and stocky, the jaguar is adept at crawling, climbing and swimming. It is a tawny yellow but ranges from a reddish-brown to black. Darker rosettes help in camouflage. The shape of the dots vary and may be solid. On the tail they may merge to form a band. The undersurfaces are white.

Jaguar HeadCredit: Wikimedia

The jaguar differs from the leopard in having larger, fewer, usually darker rosettes with thicker lines and small spots in the middle. Colour morphism occurs with near-black animals appearing in about 6% of the population. These still have spots which can be seen on close examination.

The bite of the jaguar is exceptionally powerful, so much so that a prime method of attack is to bite through the skull of prey fatally piercing the brain. Its canine teeth can also pierce the shell of armoured reptiles.

The jaguar hunts by stalk and ambush, attacking from cover with a quick pounce, leaping onto the back of the animal and delivering a fatal bite to the skull. It will even leap into water after prey. Once it has its prey, it drags it into a thicket and eats the heart and lungs first, followed by the shoulders. Jaguars rarely turn on humans.

JaguarCredit: Wikimedia

The jaguar is solitary apart from mother/cub groupings. Male territories do not overlap and boundaries are marked with scrape marks, urine and faeces. A male's territory may incorporate that of two or three females. Mostly the males take pains

to avoid each other. The jaguar is crepuscular and relatively active for a big cat.

The jaguar has the strongest bite of all felids, twice as strong as a lion and only inferior to the spotted hyena. Comparative to its size, it has the strongest bite. It can drag along a 360 kg bull and make short work of the bones. The jaguar is an obligate carnivore and an opportunistic hunter. Eighty-seven different species of prey have been identified. Large prey are preferred but it isn't too fussy. It will tackle caiman (a small alligator), deer, tapirs, peccaries, anacondas, frogs, sloths, monkeys, turtle, domestic livestock, fish, birds and rodents.

Females are sexually mature at about two years of age and males at three or four. It is believed mating occurs year-round. After mating, females then provide all the parenting. Gestation is 93 to 105 days and two to four cubs are born. The young are born blind and weaned at 3 months although they stay in the den for six months before being taken out on hunting expeditions. They stay with the mother another 1 to 2 years. Lifespan in the wild is believed to be 12 to 15 years and up to 23 years in captivity.

The jaguar is considered near threatened and numbers are declining. Habitat loss and fragmentation through deforestation has made life difficult for the jaguar. Ranchers and farmers in South America are not above killing the jaguar if it threatens livestock – or even if it doesn't. International trade in the animal (and its parts) is now prohibited. During the 1960s, over 15,000 jaguar skins were brought out of the Brazilian Amazon each year. Fortunately the implementation of CITES (Convention on International Trade in Endangered Species) of 1973 brought about a sharp decline. Trophy hunting is still permitted in Bolivia and there is no legal protection in Ecuador or Guyana.

As well as being a keystone species, the jaguar is an 'umbrella species' meaning that if it is protected, its broad home range and habitat needs will automatically ensure the protection of other species which share that range and those habitats.

The jaguar is the national animal of Guyana and Brazil.