Schilbach Pizzutto, C., Nichi, M., Geronymo Sgai, M. G. F. et al. 2008. Effect of environmental enrichment on behavioral and endocrine aspects of a captive orangutan (Pongo pygmaeus) . Laboratory Primate Newsletter 47(2), 10-13.

Our results demonstrate that, after enrichment, Karen was observed at the top of the trees 97.64% of the time, a value similar to that found by Gippoliti (2000) in free-ranging orangutans, who remained day and night up to 10 meters above the ground. This indicates that providing ropes and a high platform allowed the appearance of arboreal behavior, which is typical in orangutans (e.g., Perkins, 1992; Hebert & Bard, 2000).Karens adaptation to her new environment, evidenced by the significant increase in fecal metabolites of cortisol, lasted 15 days. This period was followed by a significant reduction of cortisol metabolites below the mean levels found during the Baseline phase. These results indicate that, after the Habituation phase, the stimuli induced by the innovations no longer resulted in a stress response, suggesting an adjustment of the animal to the new environment. It is important to note that values found for the metabolites of cortisol after the Habituation phase were significantly lower than those found during Baseline, indicating an improvement in Karens reaction to her environment.