MATERNAL GROUPING AS A DEFENSE AGAINST INFANTICIDE BY MALES - EVIDENCE FROM FIELD PLAYBACK EXPERIMENTS ON AFRICAN LIONS

Female lions roar in order to stay in contact with their pridemates an d to defend their territory against other prides. Tn doing so, however , they risk attracting the attention of potentially infanticidal nonre sident males. We used playback experiments to demonstrate that nonresi dent males are indeed specifically attracted to female roars, approach ing the roars of female, but not male, conspecifics. However, there wa s also evidence that males adjust their behavior according to the prob ability that they might execute a successful takeover. Alien male lion s were more reluctant to approach playbacks of three females roaring t han of a single female roaring; single males were more reluctant than pairs to approach female roars; and old males were more reluctant than younger males to approach female roars. Previous observational studie s have shown that female lions living in groups are more successful th an singletons at defending their cubs in direct interactions with pote ntially infanticidal males. Our results suggest that maternal groups m ay also, by roaring in chorus, minimize the chances that these encount ers occur at all.