We investigated social impacts on vocal ontogeny, through the emergence of non-inherited group membership and kinship indicators, in the vocalizations of maturing goat kids. Contrary to the prevailing views in the literature, we found that calls of kids raised in the same social groups were more similar than calls of kids from different groups, showing that kids can modify their vocalizations in relation to their social environment. This social group effect was present at both 1 week (before Bonferroni correction) and 5 weeks old. As we predicted, the group effect was stronger at 5 weeks old, when kids in the wild
would have joined their larger social groups of other kids and adults (Lickliter 1987). We also found that at