Habituation, sensitization, or consistent behavioral responses? Brown bear responses after repeated approaches by humans on foot

Abstract

Several large carnivore populations are increasing in human-dominated landscapes, but this good conservation news includes management challenges. Because of existing fear and negative human attitudes towards carnivores and potential carnivore habituation to people, better knowledge on carnivore behavior is needed to favor human-carnivore coexistence. We performed up to 8 experimental, repeated approaches on 29 radio-collared brown bears (Ursus arctos) in Sweden (195 approaches) to test if bears always avoided people or showed sign of habituation or sensitization. Bears consistently avoided the approaching humans. The proportion of bears that stayed or moved away from their initial site and their flight initiation distances did not increase or decrease with increasing number of encounters, and the bears' daily movement pattern changed consistently after each approach. Bears that moved away did so immediately, followed by a reduced movement afterwards. Bears moved less during daytime for the next three days after an approach, compared to their movement pattern before the approaches started. The initial reaction was consistent after consecutive approaches, whereas the decrease in movement in the following hours and middays was less clear after the first three consecutive approaches. The number of carnivore-human encounters may increase in human-dominated landscapes when carnivore numbers increase, but our results suggest that this should not be interpreted as an increased risk of aggressive behavior. We detected no change in the natural response of the bears, i.e., avoiding people, at the level of disturbance we created. This is a positive message for humans, but altered daily activity patterns can have negative effects on the disturbed animals, which also deserves attention.