Filling in the holes: The reproductive biology of the understudied Mahali mole-rat (Cryptomys hottentotus mahali)

Abstract

African mole-rats have provided great insight into mammalian evolution of sociality and reproductive strategy. However, some species have not received attention, and these may provide further insights into these evolutionary questions. The cooperatively breeding Mahali mole-rat (Cryptomys hottentotus mahali (Roberts, 1913)) is one such species. Body mass, reproductive-tract morphometrics, gonad histology, and plasma reproductive hormone concentrations were studied for breeding and non-breeding males and females over 1 year. This study aimed to discern if this species exhibits a seasonal or aseasonal breeding pattern and whether there is a relaxation of reproductive suppression at any point in the year in non-breeding animals. The pattern of reproductive relaxation during the wetter months is similar to other African mole-rat species. Interestingly, births and pregnant breeding females were recorded throughout the year, thus indicating an aseasonal breeding strategy, despite inhabiting a region that experiences seasonal rainfall. However, there were periods of the year favouring increased reproduction to enable an increased likelihood of offspring survival. This suggests that the Mahali mole-rat may be an opportunistic breeder possibly brought about by the benefits of living in a cooperatively breeding group and potentially moving into more arid environments that were previously unexploited by the genus Cryptomys Gray, 1864.