Task specialization and task switching in eusocial mammals

Eusocial insects often display a certain degree of task specialization, which may help maximize the efficiency of a colony. Here we tested for the presence of task specialization in a eusocial mammal. Naked mole-rats, Heterocephalus glaber, were videorecorded across multiple days in their home colony and in a neutral arena with an unfamiliar conspecific for determination of short-term behavioural profiles. They were also recorded in these settings across the birth of multiple litters to assess the stability of behaviour patterns over months. Pup care behaviour, working behaviour and colony defence were unevenly distributed among subordinate mole-rats. Furthermore, these behaviours were stable across days and months. Across days, age was positively related to colony defence and negatively related to pup carrying. We also tested whether behaviours were stable across contexts by observing pup care behaviour outside of the colony in a neutral arena. We further attempted to determine whether mole-rats' behaviours were contingent on the demands of the colony by removing the most frequent performers of pup care, colony defence and work behaviour from each colony. Results from these experiments suggest that when task specialists were no longer present, remaining animals adjusted their behaviour to fill the needs of the colony. Under these circumstances, younger animals engaged in the majority of working and pup-carrying behaviour while older animals engaged in the majority of colony defence behaviours. Thus, subordinate naked mole-rats show both task specialization and task switching.