Leopards are the most significant natural predator of chimpanzees, though lions, large snakes, crocodiles, and several other carnivores also pose threats. The biggest killer of chimpanzees by far, however, is humans. An estimated 2,021 western chimpanzees alone were killed between 2005 and 2011 to supply trade in wild meat, live animals, and body parts. Other chimpanzees are also killed by rival chimpanzee groups, making their list of threats both varied and surprisingly social.
Leopards: The Primary Natural Predator
Leopards are the predator most closely linked to chimpanzee mortality in the wild. Because they range across nearly all of sub-Saharan Africa, leopards overlap with chimpanzee populations far more than any other large cat. The best-studied cases come from Taï Forest in Côte d’Ivoire, where leopard attacks targeted chimpanzees of all ages and sexes and, at least temporarily, had a major impact on the community’s survival rates.
For decades, researchers assumed leopard predation on chimpanzees was mostly a West African phenomenon. No confirmed kills had been recorded at any of the long-studied East African chimpanzee sites. That changed when a team surveying leopard droppings at Mahale Mountains National Park in Tanzania found chimpanzee bones, including kneecaps and finger bones, inside a leopard scat. This was the first physical evidence that leopards also eat eastern chimpanzees, suggesting the threat had simply been going undetected rather than absent.
Researchers now believe leopard predation on chimpanzees has been significantly underestimated. Kills happen at night or deep in the forest, and remains are rarely found. At Taï, a single leopard may have been responsible for all the documented attacks, which hints that individual leopards can learn to specialize in hunting primates.
Lions, Pythons, and Other Predators
Lions are not a typical chimpanzee predator because the two species rarely share habitat. Lions prefer open grasslands, while chimpanzees stick to forests. But when lions wander into forested areas, the results can be deadly. When at least two lions visited Mahale Mountains National Park in Tanzania in 1989, researchers found chimpanzee remains in four separate lion fecal samples collected over several months. Analysis of the bones, hair, and teeth suggested that at least four chimpanzees were killed, including two adult females and two younger males. Because the samples were spread out over time, this wasn’t a single event but repeated predation.
At Assirik in Senegal, one of the most predator-rich chimpanzee habitats ever studied, six potential nonhuman predators share the landscape: lions, leopards, spotted hyenas, African wild dogs, Nile crocodiles, and African rock pythons. Researchers there documented one suspected predator killing of a chimpanzee, plus one case of an adult female dying after an encounter with a venomous snake.
Rock pythons provoke an especially strong reaction from chimpanzees. At multiple study sites, encounters with pythons triggered repeated physical attacks on the snake, alarm calls, and dramatic display behaviors. This intense response, a mix of fear and aggression, suggests pythons represent a real enough danger that chimpanzees have developed specific behavioral strategies against them. Pythons large enough to take a juvenile chimpanzee exist throughout their range, though confirmed kills are rare in the scientific record.
Other Chimpanzees
One of the most dangerous threats to a chimpanzee is another chimpanzee. Lethal violence between neighboring communities is well documented across study sites and appears to be a consistent feature of chimpanzee social life. Males from one group conduct patrols along territorial boundaries and sometimes launch coordinated attacks on individuals from rival groups, often killing them. The number of deaths from these intercommunity attacks far exceeds killing within a group.
Data from captive populations offer a rough sense of how significant this violence is. In accredited U.S. zoos, about 7% of all chimpanzee deaths past infancy were directly or indirectly caused by aggression from other chimpanzees. In the wild, where territorial warfare adds another layer, the proportion is likely higher. These attacks are not random. Victims are typically outnumbered, caught alone or in small parties at the edges of their territory.
Humans: The Dominant Threat
No predator comes close to humans in terms of impact on chimpanzee populations. Chimpanzees are hunted for bushmeat, captured alive for the pet trade, and killed for body parts used in traditional practices. Between 2005 and 2011, more than 643 western chimpanzees were documented as trafficked globally. Because most kills go unrecorded, researchers estimate the actual number killed during that same period averaged around 2,021.
Even when humans aren’t deliberately hunting chimpanzees, they cause serious harm. Wire snares set for other animals like duikers and bush pigs regularly catch chimpanzees instead. In one Ugandan population, nearly 20% of individuals (10 out of 52) had injuries from snares or traps, often resulting in permanent loss of a hand or foot. These injuries reduce the ability to climb, forage, and care for infants, with lifelong consequences.
The broader picture is even grimmer. Habitat destruction through agricultural expansion, logging, cattle ranching, mining, and road construction affects 76% of primate species worldwide. For chimpanzees specifically, the combination of habitat loss and direct killing through hunting and trapping represents a far greater extinction risk than any natural predator. Unsustainable human activity is now the dominant force pushing primate species toward extinction.
How Chimpanzees Defend Themselves
Chimpanzees are not passive prey. Their primary defense is collective. When a predator is detected, group members engage in mobbing behavior: surrounding the threat, screaming alarm calls, and making aggressive charges. This coordinated harassment is often enough to drive off a leopard or python. The larger the party, the safer each individual is, which is one reason chimpanzees tend to travel in bigger groups when predation risk is high.
Nest building is another key strategy. Chimpanzees construct sleeping nests in trees each night, and the height and location of these nests are directly influenced by predator presence. In areas with many large carnivores, such as Taï Forest and Issa Valley in Tanzania, chimpanzees build their nests significantly higher. They also choose positions that are hard to reach: at the ends of branches, near tree crowns, or along the edges of gallery forests where tall trees offer better vantage points and escape routes. When predation pressure drops, as it has at some sites where large carnivores have declined, nest height decreases too. Some chimpanzees in low-predation environments even build nests on the ground.
At Assirik, where the predator community is unusually diverse, chimpanzees showed a clear preference for nesting in gallery forests with taller, denser trees. Researchers interpreted this as a safety-driven choice, since these closed-canopy forests make it harder for terrestrial predators to access sleeping chimpanzees and easier for the apes to detect anything approaching from below.