Cooperative begging in banded mongoose pups.

Vivid begging displays are common in species with parental care [1, 2]. They are usually seen as the way that rival offspring selfishly compete over parental investment [3], and individuals are expected to respond to the begging of rivals by increasing their own begging intensity [4, 5]. Here I show the opposite - that potential rivals gain direct benefits from begging by littermates, so that begging behavior becomes a collective enterprise, similar to other cooperative activities. I investigate begging in communally breeding banded mongooses (Mungos mungo), where each pup forms an exclusive relationship with a single helper (its "escort"), minimizing competition over food allocation. Escorts were influenced by the total signal emanating from a litter, so that pups who begged at low rates received more food as litter size increased. Focal pups increased their begging when litters were experimentally reduced or littermates were induced to beg at low rates, but they received food at similar rates and showed reduced weight gain - indicating that they were paying a higher cost for a similar reward. These results suggest that offspring can benefit from companions despite conflicts over the allocation of parental investment [6, 7]. Such benefits provide an explanation for observed variation in the expression of parent-offspring conflict.