On the way to systematize habituation: a protocol to minimize the effects of observer presence on wild groups of Leontocebus lagonotus

Habituation is used in most field research with primates to minimize observer effects on their behavior. Despite its importance, there is little published on the methods used to habituate different taxa of primates or how these methods vary in different habitat types. We assessed changes in behavior and space use of two groups of Leontocebus lagonotus in the Ecuadorian Amazon in order to document this process. Although the subjects had not been studied before, visitors and researchers were more frequently in the home range of Group 1 than of Group 2. We followed both groups for 2 months, collecting behavioral data through scan sampling and recording the use of space (ground, understory, subcanopy, and canopy) and the routes along which we followed the groups. We then divided our data into two equivalent stages, randomized the data for each stage and looked for significant differences using Wilcoxon tests. Our results show a significant decrease in submissive behaviors toward the observer for both groups and a significant increase in resting and foraging for Group 1. In addition, Group 2 used the subcanopy significantly less and the understory more during the second stage. The routes the animals used were significantly longer in the second stage for Group 1, but not for Group 2. We conclude that our methodology is adequate to advance in the habituation of L. lagonotus in less than 2 months and that a group will habituate more quickly if it has had some previous neutral exposure to humans.