Post-weaning social behaviour within mother–offspring groups of the bushveld gerbil, Gerbilliscus leucogaster: Implications for dispersal

Abstract

Social behaviour has been implicated in the natal dispersal of several small mammal species. We studied social interactions within groups of bushveld gerbil Gerbilliscus leucogaster mothers and their weaned offspring in captivity. We examined groups (n = 8) over several weeks to assess whether mothers and juveniles tolerate one another beyond weaning, and to investigate  behavioural influences surrounding the onset of dispersal. Each group was placed in a series of interconnecting tanks,  allowing juveniles free movement between tanks but restricting the movement of the mother. In two of the eight groups the mother  produced a second litter during the study; mothers in these two groups appeared to be less tolerant of their first litter compared to mothers in the remaining groups. The remaining groups showed very high levels of tolerance throughout the study, both between mothers and their  offspring, and between siblings. Juveniles began showing independence from the mother around weaning, but although independent behaviour increased with juvenile age, there was no clear breakdown of the mother–offspring bond. In  nature, offspring probably disperse passively at around five to six weeks old if no subsequent litter is born. However, the high tolerance within these groups suggests that dispersal could be delayed under particular circumstances.

Key words: Gerbilliscus leucogaster, mother–offspring interactions, natal dispersal, natal philopatry, sibling interactions.