Chimps Vocalize With Purpose
October 17, 2013

Chimps Speak With Purpose, May Point To The Origins Of Language

Michael Harper for - Your Universe Online

After analyzing the calls of chimpanzees in the wild, scientists with the University of York now believe these animals vocalize with a purpose rather than chant and howl at random. It was previously understood that the primates would simply shout when they were alarmed or felt they were in danger. However, Dr. Katie Slocombe and Dr. Anne Schel of the Department of Psychology at York recorded calls of several wild animals in Uganda and found that these vocalizations can be interpreted in different ways and are often changed when a family member is nearby.

Related research has shown that Orangutans also use their voices to communicate very clear and concise plans with their family and even their enemies. Doctors Slocombe and Schel's study was published in the journal PLOS ONE.

Scientists once believed primates only vocalized unintentionally and out of emotion, despite their many similarities with humans. This involuntary grunting and chanting, say some scientists, could be the origins of human speech. Yet doctors Slocombe and Shel say their research shows that the chimpanzees of Uganda are quite aware of their noises and even use them with purpose.

The University of York scientists flew to Uganda to study these primates and record their calls. Before starting their field studies, the researchers located a group of chimps and observed their movements and behaviors. Then, using a model snake to startle and alarm the animals, the researchers were able to illicit a response from the chimps and record them. They noticed the chimps were more likely to sound a call if members of their group were nearby.

When a chimp saw the model snake, for example, they would chant and call continually while monitoring the rest of their group members. It wasn’t until every member of their group was safely accounted for that the startled chimpanzee stopped calling. This, say the researchers, is proof that the animals use their calls to communicate danger and safety with one another.

“Our results demonstrate that certain vocalizations of our closest living relatives qualify as intentional signals, in a directly comparable way to many great ape gestures, indicating that language may have originated from a multimodal vocal-gestural communication system,” said Dr. Slocombe in a statement.

“Observing the chimpanzees reacting to the snake model was intriguing,” said Dr. Schel. "It was particularly striking when new individuals, who had not seen the snake yet, arrived in the area: if a chimpanzee who had actually seen the snake enjoyed a close friendship with this arriving individual, they would give alarm calls, warning their friend of the danger. It really seemed the chimpanzees directed their alarm calls at specific individuals.”

In September another study on the vocalizations of primates was released which found that orangutans share travel details with their group the night before they strike out on a journey.

According to researchers from the University of Zurich, the lead orangutan will call to his mates to let them know where they’ll be heading the next day and how they’ll get there. Unless this orangutan hears about any trouble while the group is traveling, they’ll continue on the predetermined path without having to remind or guide one another.