CSG Species Accounts: Jaguar (Panthera onca)

Description and Behavior
The jaguar is the largest cat of the Americas, and the only living representative of the genus Panthera found in the New World. The jaguar’s pattern differs from that of the leopard by having larger, broken-edged rosettes around small black spots. It has a large head and stocky build, with relatively shorter limbs than others of its genus (Gonyea 1976). Melanism is frequent in the jaguar, and is inherited as a monogenic dominant to the normal golden-colored form, rather than through a recessive allele (Deutsch 1975, Dittrich 1979). Albinistic specimens are occasionally reported (Seymour 1989). Forest jaguars are not only more frequently darker, but are also considerably smaller in size than animals which inhabit more open areas. In Central American rainforest, 13 males averaged 57 kg and seven females 42 kg (Rabinowitz and Nottingham 1986, Aranda 1990), while in the Brazilian Pantanal males averaged 100 kg (n=24) and females 76 kg (n=16) (de Almeida 1984). The size difference may be due to the greater abundance of large prey species in more open environments.
More than 85 species have been recorded in the jaguar’s diet (Seymour 1989). Large prey, such as peccaries, tapirs and deer, may be preferred, but a jaguar will eat almost anything it can catch, and in the rainforest will take mammal prey species in proportion to their occurrence (Rabinowitz and Nottingham 1986, Emmons 1987). Large herbivores are more thinly distributed in rainforest than in more grassy, open habitats, where they are more likely to form groups and cluster near water, and jaguar diet in the rainforest and in savanna woodlands reflects this difference in prey availability and vulnerability (Emmons 1991). In many areas, cattle are ranched on what is essentially prime jaguar habitat, and cattle have been the most frequent prey species documented in several analyses of jaguar diet in Brazil (A. Almeida in Hoogesteijn et al. 1993, Crawshaw and Quigley in prep.) and Venezuela (Hoogesteijn and Mondolfi 1992).
Jaguars are the only big cats which regularly kill prey (especially capybaras) by piercing the skull with their canines (Schaller and Vasconcelos 1978, Mondolfi and Hoogesteijn 1986, Crawshaw and Quigley in prep.). Emmons (1987) suggests that the massive head and stout canines of the jaguar are an adaptation to “cracking open” well-armored reptilian prey, such as land tortoises and river turtles. She notes that, following the late Pleistocene extinctions of large herbivores, the jaguar and the puma were the only representatives of five genera of North American felid to persist, and speculates that the jaguar evolved to take advantage of a formerly super-abundant prey base of water reptiles.
Although the jaguar has been characterized as primarily nocturnal (e.g. Nowak and Paradiso 1983), radiotelemetry has shown that they are often active during the daytime, with activity peaks around dawn and dusk. Jaguars have been found to be active for 50-60% of each 24-hour period (Schaller and Crawshaw 1980, Rabinowitz and Nottingham 1986, Crawshaw and Quigley 1991). Crawshaw and Quigley (1991) found that mean daily travel distance was significantly larger for a male (3.3+1.8 km) than for females (1.8+2.5 km). Both sexes tended to travel further each day during the dry season. Rabinowitz and Nottingham (1986) found that radio-collared male jaguars tended to remain within small areas (average 2.5 km²) for a week at a time before shifting in a single night to other parts of their range.