Are we the only species that keeps secrets or, besides us, are there other animals endowed with the same ability? More specifically, how is it with our closest relatives, i.e. nonhuman primates? Three researchers – Francesca De Petrillo, Ylenia Nicolini, Marialba Ventricelli, co-authors of the present paper – discuss this issue, casting light, each of them, on a specific aspect of the general topic «Secrets in nonhuman primates»: the relationship between secret-keeping behavior and the theory of mind (De Petrillo); chimpanzees and the secret-keeping behavior (Nicolini); capuchin monkeys and their secrets (Ventricelli).