Can lemurs learn to deceive? A study in the black lemur (Eulemur macaco).

Deceptive behavior in primates has been the focus of a number of studies. Nevertheless, such abilities have never been demonstrated in prosimians. The authors' goal was to analyze possible deception in lemurs according to a paradigm used with simians. Three black lemurs were trained to communicate about the location of a hidden reward with a cooperative trainer. Afterward, when a 2nd trainer and lemurs competed to gain access to the reward, each subject differentially adapted its learned behavior to the context. Their performances with the cooperative trainer remained stable while they showed various behavioral adjustments when faced to the competitive trainer: 1 subject refused to participate, another preferentially withheld information, and the 3rd sometimes pointed deceptively to obtain the reward.