Play behavior and the development of boldness and caution in juvenile ground squirrels

We evaluated the relationship between play behavior and the development of boldness in juvenile Belding’s ground squirrels (Urocitellus beldingi). We observed the play behavior of juvenile U. beldingi, and conducted boldness tests at the beginning and toward the end of the developmental period during which play primarily occurs. Behavioral tests consisted of a researcher acting as an intruder, walking toward a juvenile, and noting the distance between the squirrel and intruder at which the juvenile first became aware of the intruder, and the distance at which the squirrel fled. The age of mothers was a significant predictor of the outcome of initial tests. Juveniles with yearling mothers noticed and fled from intruders at greater distances than did juveniles with older mothers. This result suggests maternal influences on the development of boldness and caution, with young of less experienced mothers developing greater caution. Distances at which juveniles first noticed and fled from an intruder increased significantly over the play period, suggesting an increase in caution across the play interval. Rates of social play were significant predictors of increases in distances to notice and flee from an intruder, with juveniles who engaged in social play at the highest rates having the greatest increases. Other studies have indicated an association in some situations between social play and increased boldness rather than greater caution. Together with these studies, our results suggest that possible influences of play behavior on boldness may vary with the context in which an animal finds itself.