Social play predicts caution in juvenile Belding's ground squirrels (Urocitellus beldingi)

Play is an important component of development in a range of mammalian species, and may provide adaptive benefits for young individuals in some cases. We evaluated the hypothesis that social play in juvenile Belding's ground squirrels (Urocitellus beldingi) promotes development of cautious responses when individuals are confronted with a potential threat. We observed the play behavior of juvenile U. beldingi across the developmental period in which play primarily occurs. To measure caution, we conducted behavioral tests on individual squirrels at the beginning and toward the end of the play period, and again when the individuals were yearlings. During tests we recorded the distances at which squirrels first noticed and fled from a human intruder. In initial tests, juveniles with yearling mothers responded to intruders at greater distances than did juveniles with older mothers suggesting maternal effects on the development of caution. Distances at which juveniles noticed and fled from an intruder increased across the play interval, suggesting increased caution to a potential threat as early development progresses. Social play was a reliable predictor of increases in caution, with juveniles who engaged in social play at higher rates having greater increases in the distance to notice and flee from an intruder. Distances to flee from an intruder at the end of the play interval were reliable predictors of distances to flee from an intruder as a yearling, suggesting consistency in cautious responses among individual U. beldingi over time. Rates of social play as a juvenile were reliable predictors of distances to notice and flee from an intruder as a yearling, suggesting that possible influences of play behavior on cautious responses extend beyond the juvenile period.