Few actions orchestrated in the animal kingdom are awarded a headline that would befit mankind. The chimpanzee, however, is the exception.

“Chimp leader assassinated by gang of underlings,” read the headline last year in New Scientist. It told the story of Pimu, who led his cohort of chimpanzees from 2007 until a violent day in March of last year when Pimu picked the wrong fight. Four chimpanzees appeared out of nowhere, according to New Scientist, and beat Pimu to death with their hands and feet. It was a grisly end for a species that, along with humans, are among the only animals to coordinate attacks on their own kind.

But such a murder was a natural action, according to a study published Wednesday in Nature. The paper, which analyzed data from 426 combined years of observation and 18 separate chimp sites, argues chimps are not driven to violence by their contacts with humans, which some scientists have previously contended. Chimps, rather, are natural born killers.

“Variation in killing rates was unrelated to measures of human impacts,”said the paper, which was researched by an international team of 30 scientists. “…The adaptive strategies hypothesis views killing as an evolved tactic by which killers tend to increase their fitness through increased access to territory, food, mates and other benefits.”

The research feeds into a lengthy debate over the nature of chimp violence, and what it means for humanity’s own propensity for murder. “We’re trying to make inferences about human evolution,” lead researcher Michael L. Wilson, an anthropologist at the University of Minnesota, told the New York Times. Even in areas where humanity’s hand and habitat loss were not discernible, the chimps conveyed the same bellicosity, the research found. It signified that competition over resources–even when abundant–drove the chimp wars.