There has been little quantitative research on the reactivity of non-human species to either an observer or to the presence of humans in general. This study describes the responses of black bears (Ursus americanus) to the presence of humans. Two pairs (male-female) and (female-female) of same-aged captive black bears kept at separate locations were observed in 60-min sessions with their behavior scanned every 30 s. 146 h of systematic observation were completed over a 30-month period.
Data for each session were collapsed into 30 two-min blocks and linear regression analysis was performed on the rates of various behavior patterns. At a relatively remote, undisturbed location rates of many behavior patterns and groupings by activity level were highly correlated with time period within the 60-min session. Behaviors that indicated resting or “relaxed” behavior increased from beginning to end of a session while behaviors requiring more energy decreased. Such large changes in rates of some behaviors apparently involve habituation to the presence of the observer. At the other location there was far more stimulation from sources other than the observer (tourists), and the bears' behavior was less affected by both the observer and other humans. Reactivity has been well-studied with humans, but more systematic studies are needed with all species to develop guidelines for both evaluating and countering reactivity.