Religion and oil are often cited as the primary drivers of conflict in the Middle East. The idea is that, without these two elements, peace might prevail across the region. However, a group of scientists examining a conflict in Africa suggests that the roots of human strife may run much deeper, tracing back millions of years.

These researchers propose that humans are inherently predisposed to violence. The inclination to divide into hostile factions persists even among those with shared interests, regardless of whether resources like food are plentiful.

To support their claim, they point to a fierce and prolonged conflict observed in the animal kingdom. In Uganda’s Kibale National Park, specifically on a hill known as Ngogo, two groups of chimpanzees have been embroiled in a brutal war for over a decade. These chimps have been strategically planning attacks and executing raids against one another with lethal intent.

Anthropologist Aaron Sandel, one of the scientists studying this phenomenon, notes the stark transformation in these animals’ behavior. “These were chimps that would hold hands,” he remarks, highlighting the profound shift. “Now they’re trying to kill each other.”

In the rainforest of Uganda, on a hill called Ngogo in Kibale National Park, two factions of chimpanzees have, for a decade, been seen planning attacks, launching raids and ripping each other apart.

‘These were chimps that would hold hands,’ says anthropologist Aaron Sandel, one of the scientists. ‘Now they’re trying to kill each other.’

Earlier this month, a paper by 21 researchers appeared in the highly regarded journal, Science. Under the title, ‘Lethal conflict after group fission in wild chimpanzees’, it revealed that by 2024, at least seven adults and 17 infants had been deliberately killed, by gangs of rival chimps.

Since then, four more killings have been reported and the full death toll is probably much higher.

In Kibale National Park there about 200 chimpanzees who started to polarise into two groups, the dominant Central tribe and a splinter group, the Westerners

The conflict drags on, the scientists add, ‘in the absence of the cultural markers often thought necessary for human warfare’. In other words, without any of the political ideology, the land grabs, the propaganda, the spiritual schisms, the historical enmities or the profiteering that usually underlie our own wars.

Tribal slaughter is written into chimp DNA, it appears. And because, going back six million years, we share a common evolutionary ancestor, that means it is also at the core of human genetics. That’s a bleak conclusion.

Both the scientists and filmmakers who have followed the Ngogo chimps have been deeply shocked by the sheer ferocity of their fighting.

Chimpanzees have long been known to be capable of violence but, until this paper was published, most naturalists assumed that every killing served a specific purpose. 

Battles broke out between alpha males vying for rights to mate with females, for instance, or between older and younger clan members when food was hard to find.

This new discovery of a prolonged, pointless war that continues because neither side knows how to end it was previously unknown in the animal kingdom – but sounds depressingly familiar in our own.

The chimps have been so closely studied for 30 years that camera teams have been able to record the running battles, like war reporters.

Around 2015, they began to observe that the population of about 200 animals was starting to polarise into two groups, the dominant Central tribe and a splinter group, the Westerners.

What caused this split is not certain, but it coincided with the natural deaths of five elders, whose presence may have had a stabilising influence on the colony.

Both the scientists and filmmakers who have followed the Ngogo chimps have been deeply shocked by the sheer ferocity of their fighting

One of the first killings was captured on video and featured in a 2023 Netflix mini-series called Chimp Empire.

The victim was an amiable male known to researchers as Pork Pie. He belonged to the Central clan, and, they said, a less aggressive chimp would be hard to find.

Affable, trusting, and none too bright by comparison with the alphas, his chief ambition in life was to find a good meal and sleep it off in comfort. When the other males went on sentry duty, patrolling their territory to defend against raids by the Westerners, he went along reluctantly. But his heart was never in it.

One afternoon, the Central chimps found evidence of a recent raid. The Westerners had discovered a hive of wild honey and smashed it open. Nearby, a fig tree was dripping with ripe fruit. While the rest of the patrol scouted the area, searching for the invaders, Pork Pie sloped off for a snack.

A smarter chimp would have stayed with his friends, seeking safety in numbers. But when the Westerners came back, Pork Pie was snoozing in the fork of the fig tree, with a bellyful of the fruit.

Director James Reed described the film crew’s anguish at discovering the gentle chimp’s shattered body, bitten and mauled to death.

‘There’s so much adrenaline,’ he said, describing the pitched battle. ‘The chimps are racing around in all directions – amazing that they’re ignoring you, because they can see you, but they’re focused on what they’re going to do.

‘We were trying to just observe and be detached, but you can’t help but become attached to some of these individual chimps and their personalities.

‘There is nothing you could do [to intervene]. It’s not a practical option. And you feel there’s nothing you should do, either, because as much as we might find it difficult to watch, this is a natural part of chimpanzee life and behaviour.’

Chimps are just like us in countless ways – including, it is now obvious, in their appetite for pointless war

Chimps can live up to 50 years in the wild, and Pork Pie was old enough to remember life before the war. It’s possible that he forgot how much danger he was in, until it was too late.

Dr John Mitani, a primatologist from the University of Michigan, studied the group long before the conflict broke out. He watched the initial population of more than 100 animals, spread across about 10 square miles, almost double in size.

‘They absolutely know the scientists are there,’ says Reed. ‘Every day, the scientists and trackers go out first thing in the morning and find the chimps. Chimps make a lot of noise, so it’s usually fairly straightforward to find them. The difficulty is keeping up with them.’

When families first met, peace reigned. ‘They start grooming each other, they start socialising, they start acting as one,’ Mitani says. Mating occurred across clans, and hunting parties swapped members without friction.

Hostilities broke out with extraordinary suddenness, on a specific day – just like a human war. Mitani and Sandel were following one group when the chimps burst into a run, galloping downhill towards another cluster.

‘All hell broke loose,’ Mitani says. After a brief fight, the smaller group retreated. This inexplicable, angry behaviour was repeated frequently over the next three years, until the ambushes and the killings began.

‘I feel like a war correspondent,’ Sandel says. ‘I want to be there to see it, but it’s sad. I’ve seen so many dead bodies of chimps.’

At the start of the war, the leader of the Central tribe was an alpha known as Jackson, who ruled through fear. To keep his subjects in line, he sometimes blew his top for no reason and ran bellowing at females and adolescents, shrieking in their faces and flailing his arms.

Around him he kept a close circle of allies, including the biggest chimp in the tribe, Miles – too old, at 40, to be a contender for boss but a loyal bodyguard and troubleshooter.

As researchers got to know the characters, some of them seemed all too human. There was the sycophantic Gus, a lowly ape willing to endure any humiliation or switch loyalty to any bigger male.

When he tried submissively to groom Jackson’s thick hair, the boss would bat him away with a flick of one powerful arm. Undeterred, Gus would shuffle across to ingratiate himself with Miles, who usually endured the attention for a little longer.

Then there was Abrams, a cocky 21-year-old with a showy trick. When the rains come, most chimps take cover, but Abrams liked to perform an ostentatious dance, leaping feet first at tree trunks.

To see this behaviour, it’s impossible not to feel how similar these primates are to us.

Scientists have long warned against the temptation to project human emotions and thoughts on to animals – but the parallels are staring us in the face.

Chimps are just like us in countless ways – including, it is now obvious, in their appetite for pointless war.