Callitrichids, small cooperatively breeding new world monkeys, have an unusual vocal communication system compared to non-cooperatively breeding primates by showing a larger vocalization repertoire and higher vocal plasticity. Additionally, callitrichids tend to share food proactively with conspecifics, i.e. without a begging attempt of the conspecifics, which seems to be linked to their cooperative breeding system. The aim of my PhD is to assess if the callitrichids’ vocal communication arose as a consequence of the extension of their tendency to share food towards sharing information. For this purpose, I will focus on the information donation behavior of common marmosets as representatives of the callitrichid family in three experimental contexts: (I) when communicating about food, (II) when warning, in particular under information asymmetry, and (III) in potential teaching situations.