When Jane Goodall observed a pair of chimpanzees poking around in a termite pile with sticks in the 1960s, it shook man’s image of himself seen the difference to the animal.
Many other abilities that were initially considered to be typically human were later found in our closest relatives: chimpanzees have friends and enemies, they understand the intentions of others and help each other. They even remember who supported them and later return the favor.
What continued to appear unique was man’s sophisticated language—until now. Scientists have now shaken this certainty as well. In a study just published in the journal Communications Biology has been published, a team led by Cédric Girard-Buttoz from the Max Planck Institute for Evolutionary Anthropology and Emiliano Zaccarella from the Max Planck Institute for Human Cognitive and Brain Sciences shows that that the language in which chimpanzees converse in the jungle is much more complex than previously thought. There are even indications that the animals form something like sentences.
For their study, the researchers analyzed 4,826 vocalizations from 46 wild chimpanzees of the subspecies Pan troglodytes verus that they recorded in the Tai National Park in south-west Ivory Coast. First, they identified 12 distinct vocalizations, including grunts, pants, screams, barks, screeches, and whimpers. According to the scientists, what all these sounds mean depends on how they are uttered, but also on the situation in which the animals are at the moment.
Grunting combined with panting expresses subservience
Next, the researchers examined combinations of these sounds and found: “Most of the sounds that the animals made individually also occurred in sequences of two units (bigrams), which in turn were embedded in sequences of three units (trigrams). ” The meaning of a sound changes when it is used in combination with other sounds. “Individual grunts, for example, are mainly emitted by the animals when they are eating,” write the scientists in their study. In combination with panting sounds, however, the grunts expressed submissiveness in the greeting. “Individual cries are made by chimpanzees when threatened, but panting cries also occur when communicating within a troop.”
The scientists identified a total of 390 different sound sequences, which presumably all have different meanings. To exaggerate a bit, one could also say that the chimpanzees form sentences. In principle, human language is also based on the ability to repeatedly combine a limited repertoire of sounds to create words and sentences.
The study is an example of how important it is to study animal behavior and abilities not only in the laboratory or zoo, but also in their natural habitat. This makes a huge difference, especially when studying how primates communicate: captive chimpanzees rarely communicate via sounds, which has led some experts to assume that humans’ closest relatives communicate primarily through gestures and that sound communication is not important. The current study now proves the opposite. In the zoo, where the animals can usually see each other, it is probably not necessary to call each other.
Still, 390 combinations is small compared to the variety of human language. And even if the study authors assume that they have not recorded all variants and that there are actually many more, one thing is clear: the differentiated language of Homo sapiens is extraordinary and in this respect actually typically human. How it came about is one of the great unsolved mysteries of evolutionary biology. There are only guesses. The psychologist and anthropologist Michael Tomasello, for example, assumes that it is a consequence of people’s irrepressible need to cooperate and exchange ideas with other people.