Influence of Tourist Group Size and Behavior on Indri ( Indri indri ) Responses During Encounters in Analamazaotra Forest, Madagascar

ABSTRACT Despite being a flagship species for tourism in Analamazaotra forest, the direct impact of tourists on the critically endangered lemurs Indri remains poorly understood. During two separate periods (November 2022 and April 2023), we monitored encounters between tourists and Indri, categorizing tourist group size into small (1–5) and large (> 5) groups, recording who the initiator of encounters was and the behaviors of both actors. Observations were recorded using ad libitum sampling. Tourists mainly initiated interactions during encounters, accounting for 65.4% of observed cases ( N  = 144/220). Indri initiated 28.2% ( N  = 62/220) of interactions while guides accounted for the remaining 6.4% ( N  = 14/220). Tourist‐initiated behaviors primarily included approaching Indri (44.5%, N  = 64/144), observing them (38.9%, N  = 56/144), remaining indifferent (9.02%, N  = 13/144), imitating their calls (6.2%, N  = 9/144), and shaking a branch and feeding them (1.38%, N  = 2/144). Only tourist‐initiated acts had a noticeable effect on Indri responses. Indri tended to avoid approaching when tourists approached, but approached when tourists looked away. Tourist's group size seemed strongly associated to Indri. Smaller tourist groups often responded by emitting Indri vocalizations, presumably unaware that they were territorial vocalizations. The territorial calls of Indri are very famous in Analamazaotra, and the guides probably explained their significance to tourists. Larger tourist groups tended to result in Indri either “looking away” or “ignoring” them. No significant difference was observed between the number of daily interactions and Indri responses. If choosing indifference instead of escaping were to limit energy expenses in Indri, conservation efforts should take this into account when educating ecotourists.