Researchers monitored two neighboring communities of wild western chimpanzees in Ivory Coast’s Tay National Park for three years and documented the tactical use of elevated terrain in “warlike” situations, Reuters reported. Information obtained during reconnaissance determines whether the chimpanzees are entering enemy territory.
At the border of dangerous territory, a squad of about 30 men patrols, climbs to the top of a rocky hill to reconnoitre. When it hears opponents too close, it retreats. There is no point in risking a fight if there is no advantage. This scenario is typical of human behavior. It turned out that it is also characteristic of chimpanzees.
Scientists at the University of Cambridge have observed this human military strategy for the first time in our species’ closest living relatives. “This shows complex cognitive skills and an ability to cooperate in chimpanzees to predict where and when to go and to act on the gathered information in a safe way,” explains biological anthropologist Sylvain Lemoine, leader of the study published in PLOS Biology.
Intergroup violence is ubiquitous among chimpanzees. Sometimes there are clashes in overlapping border areas. “Chimpanzees compete for space that includes food resources. Large territories are beneficial because they reduce competition within the group, and females reproduce more in larger territories,” says Lemoyne.
The two neighboring groups tracked in the study were about the same size, 45 to 45 animals, with 5 to 6 males and 10 to 13 females, and the rest small and juveniles. Males are usually dominant, adds BTA.
Climbing a hill does not significantly improve visual orientation and detection of rival community members. It offers better acoustic conditions for detecting opponents by sound.
Chimpanzees are more likely to enter dangerous territory if rivals are further away. Such intrusions occurred approximately 40% of the time when rivals were about 500 meters away, 50% when rivals were about 1 km away, and 60% when rivals were about 3 km away.
Chimpanzees and closely related bonobos are the species genetically closest to humans, sharing about 98.8% of our DNA. The evolutionary lines of man and chimpanzee split about 6.9 to 9 million years ago.
Studying chimpanzee behavior can provide insight into our own species. “We can better understand where we come from and what makes us human,” says Lemoine.