Bonobos call out to one another with distinctive squeals, and these sounds resemble the cries of baby humans, researchers discovered. This new discovery could also lead to a better understanding of how the talent for human speech developed.
Once known as pygmy chimpanzees, bonobos are one of the two members of the genus Pan, while the other is Pan troglodytes, or the common chimpanzee. These great apes, native to the Congo Basin in the Democratic Republic of the Congo, are currently listed as endangered.
Bonobos are similar to common chimpanzees through the large percentage of their genetic code that they share with humans. However, studying bonobos in the wild is difficult due to the unstable political situation in the Congo. Because of this, far less research has been carried out on the study of bonobo calls, compared with Pan troglodytes.
Biologists and others traditionally believed that non-human primates utilized a single call to express a single idea. One sound might be used as a warning to a potential competitor for food or a mate, while another call would signal an alarm to a neighboring group. Using a single sound in different situations, an ability known as functional flexibility, was thought to be a characteristic possessed solely by humans.
Human babies as young as three or four months have the ability to carry out calls with functional flexibility. These sounds are in addition to other calls directly related to emotions, such as crying when the baby experiences physical pain.
Zanna Clay, a researcher from the University of Birmingham, was studying bonobos in the Congo when she noticed the animals were producing a peeping sound in addition to the normal grunts and pants the primates produce.
"When I studied the bonobos in their native setting in Congo, I was struck by how frequent their peeps were, and how many different contexts they produce them in. It became apparent that because we couldn't always differentiate between peeps, we needed understand the context to get to the root of their communication," Clay said.
Researchers examined recordings of the peeps produced by the bonobos under differing conditions. Analysis revealed that these squeaky noises were identical, regardless of the events taking place in the lives of the primates when the calls were made.
"It's not easy to get access to these animals in the wild ... and this is really important data. It goes along with a growing body of evidence that suggests that primates do have quite a bit of control ... and goes against the general idea that animals are somehow constrained by their emotional state," said Simon Townsend of the University of Zurich.
This discovery pushes back the date during which our ancestors utilized context-free calls to between six and 10 million years before our own time.
Analysis of the calls of bonobos, and research into what this study could tell us about the history of human communication was profiled in the journal Peer J.
Photo: Tambako the Jaguar | Flickr
