Females of solitary- and group-living sister species of African striped mice show a similar social structure following experimentally imposed group-living

Social systems vary within and between species, ranging along a continuum solitary-living to complex societies. are emergent properties of interactions individuals, these often modulated by hormones. We investigated the behavioral hormonal consequences experimentally imposed social grouping in two sister species African striped mouse Rhabdomys, one which (R. pumilio) is group-living its natural xeric environment, while other dilectus) mesic environment. compared behavior triads age-matched, unfamiliar females each measured their serum corticosterone testosterone concentrations comparison solitarily housed controls. On day 1, both displayed mainly amicable behavior. Aggression was rare, but R. pumilio showed more aggression than dilectus females. Triads shared nests from 2 onwards, increased over time. Neither differed concentration solitary controls, had 1.3 × higher pumilio. Serum did not differ or treatments. nor at end experiment related duration shown triad members study. Both established similar structure when non-kin captivity. high amicability little aggression, indicating that environmental factors, such as resource distribution breeding season, may be important determinants organization mice tolerance. Variation occurs date, it still poorly understood how differences tolerance relate inter-specific variation systems. mouse, naturally species. studied individuals experimental groups 21 days experiment. socio-positive occurred. Individuals solitary-housed control same Our results show tolerant conspecifics, least captivity, factors might