The jaguar is mostly active at night and during
twilight. However, jaguars living in densely forested regions of the
Amazon rainforest and the
Pantanal are largely active by day, whereas jaguars in the
Atlantic Forest are primarily active by night. The activity pattern of the jaguar coincides with the activity of its main prey species. Jaguars are good swimmers and play and hunt in the water, possibly more than tigers. They have been recorded moving between islands and the shore, swimming distances of at least 1.3km. Jaguars are also good at climbing trees but do so less often than cougars. However, field work has shown this may be natural variability, and the population increases may not be sustained. Thus, the
keystone predator hypothesis is not accepted by all scientists. The jaguar is
sympatric with the
cougar. In central Mexico, both prey on
white-tailed deer, which makes up 54% and 66% of jaguar and cougar's prey, respectively. In South America, the jaguar is larger than the cougar and tends to take larger prey, usually over . The cougar's prey usually weighs between , which is thought to be the reason for its smaller size. This situation may be advantageous to the cougar. Its broader prey niche, including its ability to take smaller prey, may give it an advantage over the jaguar in human-altered landscapes. An analysis of 53 studies documenting the diet of the jaguar revealed that its prey ranges in weight from ; it prefers prey weighing , with the
capybara and the
giant anteater being the most selected. When available, it also preys on
marsh deer,
southern tamandua,
collared peccary and
black agouti. In the Brazilian Pantanal, it primarily feeds on aquatic reptiles and fish including
thorny catfish,
small-scaled pacu,
red-bellied piranha and
barred catfish. It also preys on livestock in
cattle ranching areas where wild prey is scarce. The jaguar's bite force allows it to pierce the
carapaces of the
yellow-spotted Amazon river turtle and the
yellow-footed tortoise. It employs an unusual killing method: it bites mammalian prey directly through the
skull between the ears to deliver a fatal bite to the brain. It kills capybara by piercing its
canine teeth through the
temporal bones of its skull, breaking its
zygomatic arch and
mandible and penetrating its brain, often through the ears. It has been hypothesized to be an adaptation to cracking open turtle shells; armored reptiles may have formed an abundant prey base for the jaguar following the late
Pleistocene extinctions. The jaguar uses a stalk-and-ambush strategy when hunting rather than chasing prey. The cat will slowly walk 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 capable of carrying a large kill while swimming; it is strong enough to haul carcasses as large as a
heifer up a tree to avoid flood levels. After killing the prey, it drags the carcass to a
thicket or other secluded spot. It begins eating at the neck and chest, consumes heart and lungs, followed by the shoulders. In the
Venezuelan Llanos and Brazilian
Pantanal, male coalitions were detected, which marked, defended and invaded territories together, hunted together and mated with several females. The jaguar uses scrape marks, urine, and feces to
mark its territory. The size of home ranges depends on the level of deforestation and human population density. The home ranges of females vary from in the Pantanal to in the Amazon to in the
Atlantic Forest. Male jaguar home ranges vary from in the Pantanal to in the Amazon to in the Atlantic Forest and in the
Cerrado. Studies employing
GPS telemetry in 2003 and 2004 found densities of only six to seven jaguars per in the Pantanal region, compared with 10 to 11 using traditional methods; this suggests the widely used sampling methods may inflate the actual numbers of individuals in a sampling area. Adults also
growl during courtship and mating, while cubs bleat, gurgle and
meow.
Reproduction and life cycle in the northern Pantanal In captivity, the female jaguar is recorded to reach
sexual maturity at the age of about 2.5 years.
Estrus lasts 7–15 days with an
estrus cycle of 41.8 to 52.6 days. During estrus, she exhibits increased restlessness with rolling and prolonged vocalizations. She is an
induced ovulator but can also ovulate spontaneously.
Gestation lasts 91 to 111 days. The male is sexually mature at the age of three to four years. His mean
ejaculate volume is 8.6±1.3 ml.
Generation length of the jaguar is 9.8 years. In the Pantanal,
breeding pairs were observed to stay together for up to five days. Females had one to two cubs. The young are born with closed eyes but open them after two weeks. Cubs are
weaned at the age of three months but remain in the birth den for six months before leaving to accompany their mother on hunts. Jaguars remain with their mothers for up to two years. They appear to rarely live beyond 11 years, but captive individuals may live 22 years. Two more cases of
infanticide were documented in the northern Pantanal in 2013. To defend against infanticide, the female hides her cubs and distracts the male with courtship behavior.
Attacks on humans The Spanish
conquistadors feared the jaguar. According to
Charles Darwin, the
indigenous peoples of South America stated that people did not need to fear the jaguar as long as capybaras were abundant. The first official record of a jaguar killing a human in Brazil dates to June 2008. Two children were attacked by jaguars in Guyana. The majority of known attacks on people happened when it had been cornered or wounded. ==Threats==