Contrary to predictions, leopard predation rates were not negatively, but positively, related to body size, group size and the number of males per group, suggesting that predation by leopards did not drive the evolution of these traits in the predicted way. Leopard predation was most reliably associated with density, suggesting that leopards hunt primates according to abundance. We related the species-specific predation rates to various morphological, behavioural and demographic traits that are usually considered adaptations to predation (body size, group size, group composition, reproductive behaviour, and use of forest strata). Faecal analyses confirmed that primates accounted for a large proportion of the leopards' diet and revealed in detail the predation pressure exerted on the eight different monkey and one chimpanzee species. Radio-tracking data showed that forest leopards primarily hunt for monkeys on the ground during the day. Here, we present data on the hunting behaviour of the leopard (Panthera pardus), a major primate predator in the Tai forest of Ivory Coast and elsewhere. Journal reference: American Journal of Primatology, DOI: 10.1002/ajp.Although predation is an important driving force of natural selection its effects on primate evolution are still not well understood, mainly because little is known about the hunting behaviour of the primates' various predators. That means the red colobus may not face as great a threat from them in the near future, and so could yet bounce back. ![]() Watts says the chimps are now hunting less than they did, so young males are not getting as many opportunities to acquire the skill. “The rate at which I encounter red colobus has gone way down,” he says. All had a much smaller effect than predation by chimpanzees, suggesting the chimps were mostly to blame.ĭavid Watts of Yale University in New Haven, Connecticut, says the findings are in line with his own observations of the Ngogo monkeys. Struhsaker examined other factors that might have caused the red colobus to decline, such as disease, competition with other monkey species, changes to their habitat, and predation by crowned eagles. During that time, the chimpanzees killed between 15 and 53 per cent of the red colobus population each year, taking a particularly heavy toll on young animals that had not yet reproduced. The number of red colobus killed by the chimpanzees in Kibale National Park had increased from an estimated 167 per year in the late 1990s to 322 in 2002. A previous study suggested a similar decline, but did not test its statistical significance.Įstimating changes in chimpanzee populations is more difficult due to the tendency of chimps to spend time on their own, says Struhsaker, but his team noticed that the number of chimps they have sighted over the years has risen by 53 per cent, which he says suggests that they were prospering at the increasing expense of their prey. The biggest change was seen in the red colobus population, which decreased by about 89 per cent. They have now compiled all their census data between 19 to see how the different species have faredĪll the populations changed significantly, with some growing and others shrinking. Thomas Struhsaker of Duke University in Durham, North Carolina, and colleagues have been regularly surveying the chimp and red colobus populations in Kibale, along with the populations of another six monkey species. Like the chimps in Tanzania and Ivory Coast, they are skilled hunters and work together to catch their monkey prey – typically the red colobus ( Procolobus rufomitratus tephrosceles). The chimps in question live in the forests of Ngogo, in Uganda’s Kibale National Park. This is the first time a non-human primate has been shown to overhunt another, leading to a population decline. Chimpanzees in Uganda have overhunted red colobus monkeys, causing their local population to fall to one-tenth of what it was just 33 years ago, a new study has found. Humans have a bad reputation for overhunting some animals, but a new study suggests we’re not the only ones. ![]() ![]() ![]() Can’t get enough of those yummy colobus (Tim Laman/National Geographic/Getty)
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