Why do animals play? Unravelling the functions of play behaviour in fallow deer fawns, Dama dama

The presence of humans negatively impacted fawn play, demonstrating that anthropogenic disturbances suppress natural juvenile behaviours. Importantly, fawns showed no habituation to repeated human encroachment, underscoring persistent adverse effects on wildlife. Contrary to expectations, prenatal stress, measured by cortisol accumulation in hair at birth, did not directly affect juvenile play.

Nevertheless, higher cortisol levels strongly correlated with increased flight reactivity, indicating that prenatal stress significantly impacts other survival-critical behaviours. Overall, these findings reveal that play behaviour in fallow deer results from multiple interacting proximate mechanisms involving external environmental and internal physiological states. This thesis enhances understanding of play's adaptive significance alongside its influence on social structure and highlights the detrimental consequences of human disturbance on juvenile behaviours in the wild.<br><br><i>Thesis is embargoed until 31 July 2028</i>.