Gangs of chimpanzees carry out violent attacks on individuals from rival groups to secure more resources or mates, a 10-year study in Uganda has found.
During that time, scientists recorded 18 attacks and found signs of three others carried out by a large, male-dominated community of chimpanzees at Ngogo in Kibale National Park.
In summer last year, the aggressor chimpanzees finally began to occupy the area where two-thirds of their attacks had occurred, expanding their territory by more than a fifth.
The scientists, led by John Mitani, a primate behavioral ecologist at the University of Michigan, said the chimps then traveled, socialized and ate in the new territory.
“When they started to move into this area, it didn’t take much time to realize that they had killed a lot of other chimpanzees there,” Mitani said. “Our observations help to resolve long-standing questions about the function of lethal intergroup aggression in chimpanzees.”
The findings were published yesterday in the journal Current Biology.
Anthropologists have long suspected that chimpanzees, humans’ closest living relatives, kill neighbors for land, but they have lacked any hard evidence until now.
Sylvia Amsler, an anthropologist at the University of Arkansas at Little Rock and a member of the research team, said the attacks usually occurred when the chimpanzees were on routine boundary patrols in neighboring territory.
In one attack that she witnessed, 27 adult and adolescent males and one adult female had been on patrol outside their territory for more than two hours when they surprised a small group of females from a nearby community.
“Almost immediately upon making contact, the adult males in the patrol party began attacking the unknown females, two of whom were carrying dependent infants,” she said.
The Ngogo party quickly killed one of the infants and fought for 30 minutes to wrest the other from its mother, but were unsuccessful. After an hour-long break, during which time they held the female and her infant captive, they carried on with their attack.
“Though they were never successful in grabbing the infant from its mother, the infant was obviously very badly injured, and we don’t believe it could have survived,” Amsler said.
Despite their decade of observations, the researchers said they were still not sure if the objective of the attacks had been more resources or more mates.
Mitani warned against using the research to draw conclusions about warfare among humans.
“What we’ve done at the end of our paper is to turn the issue on its head by suggesting our results might provide some insight into why we as a species are so unusually cooperative,” he said. “The lethal intergroup aggression that we have witnessed is cooperative in nature, insofar as it involves coalitions of males attacking others. In the process, our chimpanzees have acquired more land and resources that are then redistributed to others in the group.”
Nearly half of China’s major cities are suffering “moderate to severe” levels of subsidence, putting millions of people at risk of flooding, especially as sea levels rise, according to a study of nationwide satellite data released yesterday. The authors of the paper, published by the journal Science, found that 45 percent of China’s urban land was sinking faster than 3mm per year, with 16 percent at more than 10mm per year, driven not only by declining water tables, but also the sheer weight of the built environment. With China’s urban population already in excess of 900 million people, “even a small portion
UNSETTLING IMAGES: The scene took place in front of TV crews covering the Trump trial, with a CNN anchor calling it an ‘emotional and unbelievably disturbing moment’ A man who doused himself in an accelerant and set himself on fire outside the courthouse where former US president Donald Trump is on trial has died, police said yesterday. The New York City Police Department (NYPD) said the man was declared dead by staff at an area hospital. The man was in Collect Pond Park at about 1:30pm on Friday when he took out pamphlets espousing conspiracy theories, tossed them around, then doused himself in an accelerant and set himself on fire, officials and witnesses said. A large number of police officers were nearby when it happened. Some officers and bystanders rushed
Beijing is continuing to commit genocide and crimes against humanity against Uyghurs and other Muslim minorities in its western Xinjiang province, U.S. Secretary of State Antony Blinken said in a report published on Monday, ahead of his planned visit to China this week. The State Department’s annual human rights report, which documents abuses recorded all over the world during the previous calendar year, repeated language from previous years on the treatment of Muslims in Xinjiang, but the publication raises the issue ahead of delicate talks, including on the war in Ukraine and global trade, between the top U.S. diplomat and Chinese
‘IN A DIFFERENT PLACE’: The envoy first visited Shanghai, where he attended a Chinese basketball playoff match, and is to meet top officials in Beijing tomorrow US Secretary of State Antony Blinken yesterday arrived in China on his second visit in a year as the US ramps up pressure on its rival over its support for Russia while also seeking to manage tensions with Beijing. The US diplomat tomorrow is to meet China’s top brass in Beijing, where he is also expected to plead for restraint as Taiwan inaugurates president-elect William Lai (賴清德), and to raise US concerns on Chinese trade practices. However, Blinken is also seeking to stabilize ties, with tensions between the world’s two largest economies easing since his previous visit in June last year. At the