About eight months after a study was released detailing chimpanzees' "vocal flexibility," researchers published a study to refute the previous findings.

Published in the journal Current Biology, the new study claims to point out several problems with the initial study, published in Feb. in the journal PeerJ. Authors of that study formally responded with a paper published in Current Biology.

The PeerJ study found wild bonobo chimps to be capable of using a singular call in a number of different ways, flexing their vocals in a way believed to be unique to humans, BBC News reported at the time.

"There are a number of problems with the original study," James Higham, a New York University researcher who co-authored the Current Biology paper, told BBC News. "Some of these relate to the methods used, while others are fundamentally a misrepresentation of what the data actually show."

Simon Townsend, a Warwick University researcher who co-authored the PeerJ study, told BBC News authors of the original paper are standing by their work.

"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," he said. "There is a lot of variation in the data; there are clearly some individuals who are changing more than others."

The Current Biology paper asserted the different versions of the bonobos' calls are related to excitement, rather than a method of specification between two different items. In their response, the PeerJ study authors claim there is still a different vocal inflection, which proves their point.

Higham told BBC News the initial findings were "over-interpreted," and that "there are some genuine and very strong disagreements among primate communication researchers about what these types of data show, and mean."