Figure 1
From: Bonobos respond prosocially toward members of other groups
In experiment 1, bonobos could release a pin and cause high-hanging fruits to drop within the reach of an unfamiliar bonobo from neighboring groups (A). In the reaching condition, the recipient could pass his/her arm through the wide bars of the baited tunnel to signal for desire; in the blocked condition, such signals were blocked by the narrow bars (B). They released the apparatus more in the experimental condition than in the control condition, regardless of whether the recipient could signal for desire or not (C). Error bars show standard errors.
