Early social experience influences the development of stereotypic behaviour in captive-born striped mice Rhabdomys

The early life experience of captive animals, in combination with their genetic inheritance, can predispose or promote the development of stereotypic behaviour in later life. To investigate the early social effects of weaning age and the presence/absence of the father on the development of stereotypic behaviour in adulthood, we retrospectively analysed data from our captive colony of striped mice, Rhabdomys. In the first analysis, pairs of young from each litter were respectively weaned on postnatal days 12 (4 days before natural weaning), 16, or 20, and the incidence of stereotypic behaviour recorded between days 50 and 60. Early weaning (day 12) was associated with a significantly higher incidence of stereotypic behaviour than later weaning (day 16 or 20). In the second analysis, pups were raised with either the father present (biparental care) or absent (uniparental care). Biparentally reared animals showed significantly less stereotypic behaviour as adults than individuals reared by their mother alone. In both analyses, young from stereotypic mothers showed a higher incidence of stereotypic behaviour than offspring from non-stereotypic dams, with experiential and genetic effects combining to influence the adult phenotype. Together, these data indicate that the early social environment influences the development of stereotypic behaviour in adulthood, and suggest directions for future research into the mechanisms of the epigenetic effects of early social experience on the development of stereotypic behaviour, such as whether amounts of parental care received per pup cause these effects, and whether changes in stereotypic behaviour are paralleled by changes in stress responsiveness.