Differences in cooperative behavior among Damaraland mole rats are consequences of an age-related polyethism

Significance Nonreproductive group members of naked and Damaraland mole rats are thought to be organized in permanent, distinct castes that differ in behavior and physiology, suggesting that their social organization resembles that of obligatorily eusocial insects. This study tests predictions about the distribution of cooperative behavior based on the suggestion that individual differences represent a caste system. Our data provide no evidence that helpers show fixed, divergent developmental pathways or specialize in particular tasks. Instead, variation in their behavior appears to represent an age-related polyethism. The results suggest that the behavioral organization of social mole-rat groups is similar to that of other singular cooperatively breeding vertebrates, and that similarities to obligatorily eusocial insects have been overestimated.