Researchers have successfully adapted an existing coding system for human facial expressions to systematically analyse the facial expressions of bonobos. Their findings confirm that bonobos possess a repertoire of 28 distinct facial movements, of which 22 are triggered by specific muscle actions. This development opens up new opportunities for understanding how these endangered great apes communicate with one another – and how their expressions differ from those of humans. The study was conducted by an international team of scientists from institutions in Germany, Switzerland, France, the United States, and the United Kingdom, led by Dr Catia Correia-Caeiro from Leipzig University’s Institute of Biology and researchers from the Max Planck Institute for Evolutionary Anthropology.