MonkeyCall is an applied research project initiated by Erica van de Waal (Unil), aiming to obtain high-quality recordings of wild vervet monkey vocalizations in South Africa to study their behaviors and modes of communication in their natural habitat. The traditional method involves observers moving around the primates with a portable microphone, recording as many vocalizations as possible. This method is suboptimal because the distance between the observer and the animal reduces the recording quality, especially for soft cries such as lip-smacking used in grooming contexts. Additionally, many cries occur when the monkey is in motion, such as during conflicts, group encounters, or predator harassment, making it challenging for the observer to be in the right place at the right time and significantly limiting the size of the recorded call sample.
A high-tech device weighing less than 100 grams
Thanks to an internal collaboration at The Sense (Haute Ecole d’Ingénierie and Unil), the MonkeyCall project was established to address the challenge of obtaining high-quality recordings of monkeys studied by Professor Erica van de Waal in South Africa. The ethologist partnered with the PI of the Neurodevices unit at The Sense, Professor Benedetta Franceschiello. The latter supervised a team of engineers from her institution, Haute Ecole d’Ingénierie of HES-SO Valais-Wallis, to design a custom microphone for the project. It is a collar powered by a battery and a low-power system that was integrated into a device weighing less than 70 grams, produced at HEI through a 3D printer.
Ultimately, this project will enable the collection of natural vocal interactions. Moreover, the collars will record various other types of sounds that can be used, for example, to detail the vocal repertoire of vervets and link it to individual characteristics (age, rank, kinship, group membership…) of the caller. This project will benefit other research requiring high-quality vocalizations, such as multimodal communication experiments, and could also be applied to new research avenues, such as combinations of calls in wild vervet monkeys.