Speaker
Description
While many species have been shown to act prosocially by providing a benefit to conspecifics, the evolution of prosocial behaviour remains incompletely understood. Among other factors, heightened social tolerance and cooperative breeding have been proposed to facilitate prosocial behaviour. However, recent studies reported conflicting results as some cooperatively breeding species behave less prosocially than expected. Therefore, a study spanning a broader range of social and especially infant care systems is needed, in order to gain a better understanding of the evolutionary roots of prosocial behaviour. Grey mouse lemurs (Microcebus murinus) are interesting in this regard because they raise their infants either cooperatively or solitarily, suggesting that they should exhibit prosocial behaviour. We tested 10 wild grey mouse lemurs in Kirindy Forest, Madagascar, in a prosocial choice test (PCT) in order to assess their prosocial tendencies. We presented individuals with four distinct tokens each representing one of the four possible reward outcomes, i.e. food for themselves, for a partner, for both or neither. In addition, we assessed the level of social tolerance by offering each dyad pieces of high value food in an arena and observing their affiliative and aggressive interactions during and after feeding. Contrary to our expectations, grey mouse lemurs showed no preference for prosocial options and instead consistently chose the outcome that exclusively benefitted themselves. These results do not support the notion that allomaternal care predicts the prevalence of prosocial behaviour.
