We thank Planète Sauvage and the dolphin trainers for their cooperation, as well as Martin Böye, Françoise Joubaud and Maxime Hervé for their assistance. This study was funded by A.N.R. (grant ORILANG), I.U.F, and A.N.R.T. (grant CIFRE).

Conflict of interest

The experiments described in this paper comply with the current laws of the country in which they were performed. The authors declare that they have no conflict of interest.