Unravelling complex associations between physiological state and movement of African elephants

Despite the identification of internal state as a fundamental component of animal movement, the effect of an individual's internal physiological state on movement remains poorly understood. African elephants (Loxodonta africana) alter their behaviour in response to their physiological state, and elevated stress hormone concentrations have been associated with reclusive behaviour and aggression towards humans. Thus, a better understanding of the link between internal physiological state and movement is important in advancing the field of movement ecology, and the ecology and management of elephants. We compared the movement paths of African elephants in two physiological states (basal and elevated stress hormone levels) to understand the variation in the use of space in relation to the proximity of environmental features and refugia. We documented differences in the elephants' use of space along movement paths by physiological state. Elephant family groups in a basal physiological state tended to venture away from refugia and commercial tree plantations, and use areas in closer proximity to fresh water. In contrast, elephant family groups in an elevated physiological state tended to use areas near refugia and commercial tree plantations. The use of commercial tree plantations during elevated states highlights an important concern for human safety in the context of human-elephant conflict. Synthesis and applications. Our findings suggest that fine-scale movement patterns and the use of specific environmental features by elephants are associated with differences in elephant physiological state. Therefore, future attempts to describe or predict typically complex animal movement could be enhanced by incorporating measures of their physiological state. Given that elephants are more prone to habitat disturbance and aggression when in an elevated physiological state, information about elephant movement behaviour could be used in combination with real-time tracking data to predict when and where elephants are potentially in elevated physiological states and limit human access to these areas, which might mitigate human-elephant conflict.