Gorillas and chimpanzees do fight, and these encounters can be brutal and lethal. While these two great ape species often coexist peacefully in Central Africa’s rainforests, recent field observations have documented rare but significant instances of violent inter-species conflict. These fights are organized attacks that reveal a complex dynamic between our closest living relatives. This aggression is rooted in environmental pressures and behavioral differences.
Shared Habitats and Coexistence
Conflict is possible because chimpanzees and gorillas share overlapping geographical ranges, particularly the western lowland gorillas and the central chimpanzees. Both species move through the same tropical forests in countries like Gabon and the Republic of Congo. Despite this proximity, their interactions are typically relaxed, and they generally employ avoidance strategies to minimize direct competition.
Gorillas are far larger, primarily terrestrial herbivores, foraging for leaves, stems, and pith. Chimpanzees are more arboreal and have a broader, omnivorous diet that includes insects and meat. This difference in ecological niche allows them to partition resources, enabling their co-occurrence. Researchers have even observed peaceful interactions, including co-feeding in the same fruit trees.
Primary Drivers of Inter-Species Conflict
This delicate balance of coexistence can shatter when primary drivers, mainly resource competition and predatory risk, lead to aggression. The most significant motivation appears to be direct competition over seasonally scarce, high-value food sources like fruit. Fruit availability for both species can drop dramatically, and the two lethal encounters documented in Gabon occurred during periods of low fruit abundance.
The second major driver of conflict relates to predatory behavior, as chimpanzees are known to hunt and consume smaller monkeys. While adult gorillas are too large and formidable to be prey, juvenile gorillas present a potential target. Chimpanzee communities may view young gorillas as a source of protein or attempt to eliminate a future competitor. Male chimpanzees, who are highly territorial, may instinctively react to the gorillas as competing resource users during territorial patrols.
Documented Aggressive Encounters
The clearest evidence of lethal fighting comes from two specific incidents observed in 2019 at Loango National Park in Gabon. In the first encounter in February, 18 chimpanzees from the Rekambo community attacked five western lowland gorillas, including a silverback, three adult females, and an infant. The confrontation lasted 52 minutes, during which the chimpanzees formed coordinated coalitions to overwhelm the silverback.
The male chimpanzees successfully separated the infant gorilla from its mother and killed it. The second lethal attack occurred in December of the same year, involving 27 chimpanzees clashing with seven gorillas for nearly 80 minutes. In this instance, the chimpanzees again targeted and killed an infant gorilla, which was subsequently consumed by one of the aggressors. These observations were the first documented instances of chimpanzees killing gorillas, demonstrating that these inter-species attacks can be highly organized and fatal.
Factors Determining Conflict Outcomes
The outcomes of these rare conflicts are heavily influenced by the distinct social and physical strategies of the two species. Gorillas rely on their immense size and strength; an adult male silverback can weigh over 350 pounds and uses powerful chest-beating and charging displays as a defense. During the Loango attacks, the silverback actively defended his group, injuring several chimpanzees and throwing one of the adolescents into the air.
The chimpanzees’ advantage lies in their superior numbers, coordination, and aggressive coalitionary tactics. Groups of up to 27 chimpanzees were able to surround and overwhelm the larger silverback. Their cooperative aggression allowed them to distract the main defender and focus on separating the vulnerable infants from their mothers. This difference highlights how chimpanzees’ intelligence and social organization overcome the gorillas’ sheer physical power when attacking smaller, isolated individuals.