Campbell’s monkeys appear to combine the same calls in different ways, using rules of grammar that turn sound into language.
Whether their rudimentary syntax echoes the speech of humanity’s evolutionary ancestors, or represents an emergence of language unrelated to our own, is unclear. Either way, they’re far more sophisticated than we thought.
“This is the first evidence we have in animal communication that they can combine, in a semantic way, different calls to create a new message,” said Alban Lemasson, a primatologist at the University of Rennes in France. “I’m not sure it has strong parallels with humans, in the way that we will find a subject and object and verb. But they have meaningful units combined into other meaningful sequences, with rules imposed on how they’re combined.”
Lemasson’s team previously described the monkeys’ use of calls with specific meanings in a paper published in November. It detailed the monkeys’ basic sound structures and their uses: “Hok” for eagle, “krak” for leopard, “krak-oo” for general disturbance, “hok-oo” and “wak-oo” for general disturbance in forest canopies. A sixth call, “boom,” was used in non-predatory contexts, such as when calling a group together for travel or arguing with neighboring groups.
Full story here.