Kin discrimination and female mate choice in the naked mole-rat Heterocephalus glaber

Naked mole-rats are fossorial, eusocial rodents that naturally exhibit high levels of inbreeding. Persistent inbreeding in animals often results in a substantial decline in fitness and, thus, dispersal and avoidance of kin as mates are two common inbreeding avoidance mechanisms. In the naked mole-ra t evidence for the former has recently been found. Here we address the latt er mechanism by investigating kin recognition and female mate choice using a series of choice tests in which the odour, social and mate preferences of females were determined. Discrimination by females appears to be dependent on their reproductive status. Reproductively active females prefer to asso ciate with unfamiliar males, whereas reproductively inactive females do not discriminate. Females do not discriminate between kin and non-kin suggesti ng chat the criterion for recognition is familiarity, not detection of gene tic similarity per se. In the wild, naked mole-rats occupy discrete burrow systems and dispersal and mixing with non-kin is thought to be comparativel y rare. Thus, recognition by familiarity may function as a highly efficient kin recognition mechanism in the naked mole-rat. A preference by reproduct ively active females for unfamiliar males is interpreted as inbreeding avoi dance. These findings suggest that, despite an evolutionary history of clos e inbreeding, naked mole-rats may not be exempt from the effects of inbreed ing depression and will attempt to outbreed should the opportunity arise.