I am often asked by visitors what species I consider to be the most dangerous. When I am in a humorous mood my answer usually includes humans or bacteria, but sometimes I clarify the question: what animal would make me the most frightened if it escaped? Actually, my answer could be the jaguar, even if it is not as dangerous to humans in the wild as lions, leopards and tigers. They are powerful, athletic, brave and aggressive – and tragic zoo events in the past also confirm its dangerousness. Nevertheless, I also admire them for of these features. In the following I will write about this species and some advices on how to keep them in zoos.
The jaguar (Panthera onca) is the largest cat in America and it is the only big cat (Pantherinae) which lives on this continent. Its relatives are the other members of the Panthera genus (lions, leopards, tigers). Current fossil evidence suggests that the genus only arose in the last 2-3 million years. Although morphological similarities imply a monophyletic origin among these big cats, according to mitochondrial DNA (mtDNA) evidence it appears that the jaguar shared its last ancestor with other big cats about six million years ago, therefore a polyphyletic origin looks more possible.
It is still a question how many subspecies exists. A taxonomic revision of Panthera onca (Pocock, 1939) distinguished 8 subspecies instead of 24 as before, another source (The Mammal Species of the World) added one other:
P. onca onca (Linnaeus, 1758) - Venezuela, south and east to Rio Grande do Sul in Brazil
P. onca palustris (Ameghino, 1888) - Matto Grosso, Paraguay and northeastern Argentina
P. onca peruviana (Blainville, 1843) - Coastal Peru
P. onca centralis (Mearns, 1901) - Central America – El Salvador to Colombia
P. onca hernandesii (Gray, 1857) - Western Mexico
P. onca arizonensis (Goldman, 1932) - Eastern Arizona to Sonora, Mexico
P. onca veraecrucis (Nelson and Goldman, 1933) - Southeastern Mexico to central Texas
P. onca goldmani (Mearns, 1901) - Yucatan peninsula to Guatemala and Belize
P. onca paraguensis (Hollister, 1914) - Paraguay
Later genetic (Eizirik et al. 2001, Ruiz-Garcia et al. 2006) and morphological (Larson 1997) researches did not support the existence of these discrete subspecies and suggested the need for a revision of the subspecies level. Eizirik found evidence for four incompletely isolated phylogeographic groups (Mexico-Guatemala; southern Central America; northern South America; South America south the Amazon river), therefore the endangered species programmes in zoos actually consider jaguars to belong to one species without distinguishing subspecies.
Jaguars have a large distribution area, they are found from southern Arizona and south of New Mexico toward northern Argentina. However, populations have been reduced or eliminated in several areas and jaguars are extinct in El Salvador, Uruguay, the northern parts of Brazil, grasslands of Argentina and large portions of Mexico. They are now estimated to occupy only about 46% of their historical range. Jaguars died out in the US around 1900, but in the late 1990s several sightings occurred in Arizona.
Jaguars prefer dense, moist tropical lowland forests, but they are also found in shrublands, reed thickets, coastal forests and swamps. They are strongly associated with the presence of water. Although jaguars have been reported form elevations as high as 3000 m, they prefer lowland areas and avoid montane forests. Jaguars have never been sighted in the high plateau of central Mexico and in the Andes above 2700 mm, but they have been reported as high as 3800 m in Costa Rica. Jaguars resemble tigers (Panthera tigris) in their habitat requirements. They also require three habitat characteristics to support healthy populations: a water supply, dense cover and sufficient prey. They climb well and they are excellent swimmers. Although jaguars can be active any part of the day, they are primarily nocturnal felids and they are most active at predawn and after dusk. They usually tend to rest between morning and afternoon. They rest and sleep in thick cover, sometimes in caves or in large holes in riverbanks and they also prefer horizontal tree limbs.
Jaguars are powerfully built animals. They have the largest bite force quotients (BFQ, the quotient of an animal's bite force divided by its body mass) among the big. Male jaguars are generally 10 to 20% larger than females.
Jaguars eat a wide variety of prey, over 85 species have been reported in their diet. They prefer large animals, such as peccaries, deer, capybaras and tapirs. They also prey on porcupines, caimans, turtles, giant snakes, fish, large birds and many other animals. Jaguars always attack from cover, usually from a ‘blind’ side. They pounce on the prey and usually bite the throat, as other big cats. However, they often attack with a precision biting to the back of the skull. Jaguars kill crocodilians by biting through the neck and severing the cervical vertebrae. When eating a turtle, the jaguar introduces its paw into the shell through the opening and scoops out the flesh without breaking the shell. After killing prey, it drags it to a secluded spot where it eats it.
Jaguars are solitary animals. Females have a 25-38 km2 home range, which is approximately half of the territory of a male. The home range of a male is typically encompassed by 2-3 female territories. Males defend their territory against other jaguars, except subadults and females. Jaguars advertise territories through vocalizations, scraping the ground and trees, and defecating and urinating on prominent locations. The daily travel distance of males is about 3.3 km and about 1.8 km for females.
According to Almeida’s observations (1974), jaguar females do not have a set breeding season. He also observed that females in heat move about searching and calling for a mate outside their territory. Males answer those calls and travel to meet the females, which may lead to competition between males. Although they are solitary, it is not uncommon for a female to travel with one or two males during oestrus. But females do not tolerate the presence of males when they have cubs. The reason of it may be the possibility of cannibalism. However, a witness reported a family of jaguars walking together: a female, a male and two large cubs. It could indicate a limited social life beyond courting.
The jaguar’s oestrus cycle is usually 37 days with the oestrus lasting 6 to 17 days. Mating typically increases in number from December to March and the cubs are usually born during the wet season (91-111 days after mating), when prey is more abundant. Cubs are born with eyes closed, which opens at around 2 weeks. The 5-6 months old cubs start to learn to hunt from their mother. Offspring leave their mother when they are almost two years old. Then young males start a nomadic life until they can establish their own home range. One observation described a young female sharing its territory with her mother, although both lived alone.
Gestation period: 91-111 days
Birth weight: 820 g
Number of offspring: 1-4
Age of weaning: 5-6 months
Age of sexual maturity: females: 12-24 months, males: 24-36 months
Lifespan: 20-28 years in captivity, 11-12 years in the wild
Jaguars – as one of the largest predator in America – had an important role in the mythology and life of pre-Columbian people. About 25 hundred years ago the Olmecs were considered to be the first to worship the jaguar. Mayas considered jaguars to be a personification of fear and death. Jaguar knights were Aztec elite warriors. The present common name of this big cat comes from the Guarani Indian word yaguara, which means ‘a wild beast that kills its prey in a single bound’.
Usually jaguars do not attack humans without being provoked. Occasionally jaguars have been observed following humans, but this is thought to be to ‘escort’ them out of their territory. This big cat very rarely turns to man-eating, but a particular jaguar was reported as a man-killer in Xarayes Marshes Region in the middle of 20th century. Its name was ‘Assassino’, and it killed humans but did not feed on them as there were many prey species present (cattle, marsh deer and dogs).
Humans are more dangerous to jaguars than vice versa. Deforestation eliminates their habitats, fragmentation isolates jaguar populations. People compete with jaguars for prey, and despite protection, hunters shoot jaguars on sight. Killing of the possible prey animals causes problem too. An estimated 27% of jaguar range is depleted of wild prey, therefore they tend to hunt for cattle and other domestic animals and ranchers consider them pest species. Commercial hunting and trapping for their pelts has declined because of anti-fur campaigns, but poachers still kill jaguars for paws, teeth and other products.
IUCN: near threatened (4)
CITES: I. (EU: A)
Estimated number in the wild: unknown, 2.2-8.8 animals/100 km²
Estimated number in zoos: about 400 (according to ZIMS)
Jaguar in the zoo
When we build an enclosure for jaguars, we should consider their extreme power and agility. The fence should be no less than a 6 gauge (4.11 mm diameter) wire mesh. The recommended aperture size is 5x10 cm, but 5x5 cm is recommended in keeper working areas. Lightweight mesh is not appropriate. A flexible mesh increases the potential of damaging the teeth and the mesh itself if the jaguar bites and pulls it. It is recommended to use an electric fence to hold the jaguar back from getting in contact with the fence. They are extremely strong and fast animals, so we need strong and safe elements in the enclosures, for example at the doors, in corridors, the fence etc. As they are excellent climbers we need to cover the outdoor enclosure. If a dry moat is used, it should be at least 7.6 m wide with a 4.6 m high wall to prevent jumping out. Chester Zoo (UK) built an open enclosure which has a 5 m high fence with deflectors at the edge, pointing in a 90º angle from the fence into the exhibit.
According to the Jaguar SSP the outdoor enclosure should be at least 27.9 m2 with 50% additional square footage per each specimen. The indoor enclosure should also be at least 27.9 m2 (6x4.6 m) with the minimum height of 2.4 m, and the optimal height of 3.7 m. Shift cages should be no less than 2,4x2,4x2,4 m (5,8 m2). In my opinion they need more space, therefore a new exhibit should be larger with many hiding and resting possibilities (for example dense vegetation), and 2-3 levels above the ground. For this reason we have to build a complex climbing structure, with thick horizontal tree branches or shelves for resting. We could provide thinner branches, they can walk on those as well, and as jaguars like water, we also need to provide a pond for them.
Where the summer is hot, they need shelters and water, especially when the temperature exceeds 31 degrees Celsius. We should provide heating when the temperature drops below 10 degrees Celsius. However, jaguars can tolerate conditions down to -1 degrees Celsius where they have adequate shelters. We should maintain a relative humidity of 30 to 50% in their house. Proper ventilation is also important.
For managing a breeding pair it is recommended to build an adjacent separation facility which is appropriate for long-term separation. The male needs to be kept separately when the female has cubs and such a facility is also useful for introducing procedures. We should always feed and keep adults separately indoors.
It is necessary to provide an isolated birthing den that has low-light capabilities and reduced human foot-traffic activity. The mother and cubs need to be separated from the male because he could kill the offspring.
The diet for adult jaguars is about 2 kg meat/day, but usually they are not fed every day. It is recommended to give varied meat from fish to horsemeat and to give whole animals as many times as possible (fur, feathers, bones, offal). Cats cannot convert provitamin A compounds to retinol, so retinol, retinyl acetate or palmitate is required in the diet. In addition, a dietary source of niacin is also required. A whole animal diet is a good source of these vitamins. My experience is that they need environmental enrichment (for example hanging a piece of meat) and they are ‘perfect performers’ in feeding shows.
Tragic cases to learn from
The jaguar is considered to be one of the most dangerous zoo animals. There have been several fatal accidents caused by these big cats. In Georgetown Zoo (Guyana) a jaguar killed its handler and escaped in 2000, In Vienna Zoo (Austria) 3 jaguars killed a zoo-keeper in 2002, in Denver Zoo (USA) a male jaguar mauled a keeper to death in 2007. The reason for these accidents was that keepers made a mistake by entering the enclosures while the jaguars were in it. In these cases the jaguars attacked the human in no time. In Doué-la-Fontaine Zoo (France) two jaguars escaped from their enclosure after scratching away at the earth under the perimeter fence and slipping through the gap. One of them moved towards a group, the other attacked and killed a young boy and the father, who tried to defend his son, was seriously injured.