Evaluating a Primate Sanctuary: Population assessment of the Common Squirrel Monkey (Saimiri sciureus) on Sumak Allpa, Ecuador

The common squirrel monkey (Saimiri sciureus) population on Sumak Allpa was assessed during 33 observation periods between November 5th and November 24th of 2012. Sumak Allpa is a 113.15-hectare island on the Napo River in the Orellana Province of Amazonian Ecuador that has been functioning as a primate sanctuary since 2005. Squirrel monkeys were surveyed during 1 to 3 hour observation walks in the mornings, afternoons, and evenings. During two occasions, the island was divided among multiple observers at the same time, including one observer in a canoe on the exterior of the island, to allow more coverage of the island and differentiation between multiple troops on the island. There was found to be one large troop, containing a maximum of 17 adults or juveniles and 3 infants (between 2 and 4 weeks of age), as well as an independent individual that likely separated from and joined the large troop frequently. A positive growth rate of 0.875 births/month in 2011 and 0.3075 births/month in 2012 was calculated using current and past data from the island (Latimer & Stout 2011) Sighting locations indicate a habitat preference for disturbed and island edge forest dominated by bamboo and heliconiaceae vegetation. The large troop was found to sleep in the same trees (two tall palms) in all but one observation evening, indicating high fidelity to sleeping sites. Behavioral recordings demonstrated significantly higher allocations to food-related activities (travel and forage, stationary forage) than other activities, accounting for 62% of all activity, and a high percentage of travel (travel, travel and forage), accounting for 72% of all activity. Very little aggression or social play was observed. This study demonstrates a positive growth and success of S. sciureus on Sumak Allpa, suggesting that the island functions effectively as a sanctuary for this species. Further research is needed to clarify and expand on results of this study, but the given results are significant in supporting sanctuaries such as Sumak Allpa in the protection and recuperation of the common squirrel monkey, as well as other exploited primate species.