the last one caused a big change in their way of living

For ten years, in Kibali National Park (Uganda), a silent and brutal war was fought. Its protagonists were not humans, but the community of Ngogo chimpanzees largest known, which maintained a constant conflict with its neighbors until they ended up exterminating them to keep their territory. Now science has wanted to find biological meaning in this, and it has succeeded.

Something natural. From the outside, this conflict can be seen as something very bloody, like the one we see between humans themselves to dominate a specific territory. But science believed that there was something more behind it, and in the end it has been seen that these wars They are more natural than we think within nature itself. And it gives us a concrete idea of ​​how the minds of these animals work.

The PNAS scientific journal just found the biological logic behind this massacre, and has not hesitated to confirm that we are facing an evolutionary strategy very profitable. After the victory, the females in the winning group not only doubled their fertility, but infant mortality plummeted.

A spoil of war. The investigation, led by Brian Wood and veteran anthropologist John Mitani, puts numbers to this brutality. And in this lapse of time the Ngogo expanded their domains by 22% at the cost of eliminating the neighbors who were occupying it in that case.

But just like humans, we often create wars. to get more resourcesanimals seem to do something similar. This territorial expansion brought with it a great abundance of food resources that completely transformed the demographics of the group.

To get an idea, the researchers in this case compared data from the three years before the conquest with those from the three years after. In this case it was seen that before the victory there were only 15 births in the group, while after the victory there were 37 new offspring. And it is not something random, since it is the first time that cooperative killing between groups has been linked to “territorial gain and greater reproductive success.”

The biological sense. But beyond the fact that more chimpanzees are born in this environment, it has also been seen that much more survive. And in the chimpanzee population, infant mortality is really high because they suffer from serious malnutrition at the beginning of their lives, as well as diseases or infanticide.

The data is quite clear. Before winning the war, 41% of the offspring died before they were three years old. After annexing neighboring territory and eliminating border threats, that figure radically dropped to 8%.

Because? The equation is quite simple: more food in the environment, less competition and greater security as there are not so many enemy incursions that kill their young.

Josep Call, a primatologist at the University of St Andrews, defines it as “biological rationality”. It is not a moral decision, it is pure natural selection: the genes of those who successfully apply this violence are much more likely to perpetuate themselves.

Death patrols. A question that we can ask ourselves in this case is how an animal with these characteristics can be organized to go to war. And although we may think that they do it without thinking about it first, the reality is that they organize very well calculated border patrols in their territory.

Upon reaching the border, these animals completely change their behavior, as they become much quieter to maintain stealth, with a strategy that is quite similar to what we can see in a human military exercise.

The moment they encounter a rival group, if they are outnumbered they know that they will not be able to win and the smartest thing to do is to retreat. But if the situation is contrary, it will be attacked without mercy.

Attacks include hitting, biting and dismembering. It is a coordinated violence that, in the case of the Ngogo, was favored by an unusual demographic factor: they had a disproportionate number of males, which allowed them to form patrol “squads” that were more lethal than those of their neighbors who did not have this advantage.

War? Although the parallel with human conflicts is inevitable, scientists prefer the term “intergroup violence.” The reasons that exist to defend this difference are that among chimpanzees there is no ideology, but rather they do it exclusively out of biological necessity, such as having food or providing for the smallest members of the community. And the truth is that annihilating the neighbors is one of the smartest ways to achieve this.

Images | Satya deep

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