The controversial study claimed that chimpanzees adapt their grunts to facilitate communication with new neighbors.

Three researchers have now written to the journal Current Biology suggesting that there may be something wrong with the results, which were taken from a group of chimps who moved from a safari park in the Netherlands to Edinburgh Zoo, Scotland, according to the BBC.

Primatologists Erupt In Debate Over Chimpanzees Accent Study

Chimpanzees study criticized by other primatologists

“There are a number of problems with the original study,” said Dr James Higham, from New York University. “Some of these relate to the methods used, while others are fundamentally a misrepresentation of what the data actually show.”

The scientists behind the original study have spoken out in defense of their work. Dr Simon Townsend of Warwick University, who co-wrote the original study with colleagues in York and St Andrews, told the BBC: “We think that we’ve addressed the points that they bring up. It’s an interesting critique of our research – and this is exactly how science works.”

The work related to a change in the call for apples used by the chimps. Over time the chimps apparently changed the call to match that used by their new neighbors, and it became lower-pitched and less enthusiastic despite the fact that they continued to enjoy eating apples.

Debate rumbles on between different camps

Now scientists are questioning whether the calls were ever very different. They have re-plotted the data collected by the original team and emphasized the similarities between the calls used by both groups of chimps, showing how scientists can draw distinct conclusions from the same set of data.

Even if they accept that the calls did change, the critics argue that it is due to a change in accent rather than learning a new call. One critic, Dr Higham, told the BBC that it was necessary to discuss the research because it was “widely publicized (and over-interpreted),” and said that there was no intention of “trying to tear down other people’s research”.

“There are some genuine and very strong disagreements among primate communication researchers about what these types of data show, and mean,” he said in an email.

Although it seems likely that the debate will rumble on for the foreseeable future, Dr. Townsend also believes it is a “useful exchange” that could prove valuable to others in the field.