Date of Award


Document Type



College of Arts and Sciences

Degree Program


Degree Name

Master of Science

Thesis Advisor

Janice Chism

Committee Member

William Rogers

Committee Member

Cynthia Tant


Anti-predator behaviors of free-ranging groups of equatorial saki monkeys (Pithecia aequatorialis) were recorded in the Área de Conservación Regional Comunal Tamshiyacu Tahuayo in the Peruvian Amazon to determine whether individuals responded in predator-specific ways to calls of aerial and terrestrial predators. Previous studies have shown that several species of Old World monkeys possess these discriminative abilities, but few have explored this question in New World monkeys. The ability to recognize predators and to respond appropriately is important for survival. Thus, we predicted that equatorial saki monkeys should respond in predator-specific ways, both vocally and behaviorally, to aerial and terrestrial predators. To investigate this, we simulated the presence of predators by playing recordings of harpy eagle calls (Harpia harpyja; an aerial predator) and ocelot growls (Leopardus pardalis; a terrestrial predator) to wild saki groups. Response variables measured included individuals’ vocalizations, movement, and gaze orientation. Between June and August 2016, we conducted 24 playback trials on 16 individuals. Chi-squared goodness of fit and Fisher’s exact tests revealed that alerted or predator-specific responses were given more often than no response at all following the playbacks of predator calls. Thus, while additional confirmation is needed, our data provide preliminary evidence that saki monkeys possess predator specification capabilities.