Download or read book Risk Perception, Alarm Call Usage, and Anti-predator Strategies in an Amazonian Primate, Pithecia Rylandsi written by Dara B. Adams and published by . This book was released on 2020 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Primates are confronted with threats of predation on a regular basis, but much is unknown regarding how they perceive and respond to these threats. Even less is known about how predators respond to primate anti-predator behaviors. Thus, key questions remain: How do primates cope with the possibility of being eaten and do these coping strategies thwart hunting by predators? This dissertation investigates these questions using a newly identified primate species, Rylands’ bald-faced saki monkeys (Pithecia rylandsi), one of their main felid predators, ocelots (Leopardus pardalis), and audio and visual simulations of other predators. Specifically, I conducted experiments on wild saki monkeys in the Peruvian Amazon using audio playbacks of predator vocalizations and life-size decoys of their main aerial and terrestrial predators. I also carried out playback experiments on the predators themselves using audio broadcasts of monkey alarm calls. This experimental design allowed me to test the ability of sakis to recognize predators based on acoustic and visual cues, determine how they respond based on predator class, location, and context, as well as to examine what information might be conveyed in their alarm calls and how these calls cause changes to predator behavior. Results from playbacks show that sakis are able to identify predator types (aerial vs. terrestrial) based solely on vocalizations, but they do not exhibit predator-specific escape responses to terrestrial predators based on acoustic cues alone. While sakis respond to harpy eagle shrieks appropriately by descending the canopy, they exhibit no clear movement patterns upon hearing jaguar growls. In contrast, visual jaguar models consistently elicit fast approaches, mobbing-style responses, and long alarm calling bouts. Visual harpy eagle stimuli elicit predator-specific whistle calls that are brief and quiet in nature, characteristics that make them difficult to locate in the forest matrix. Additionally, whistle calls are most often accompanied by escape behaviors. Thus, these calls are likely used to alert conspecifics to raptor presence while simultaneously avoiding advertisement of the caller’s location. Sakis respond to ocelot models with long bouts of chipper calls that are interspersed by periodic chucks and growls. These calls are noisy and chaotic, with call features that make them easily locatable. Playbacks conducted on radio-collared ocelots show that chipper calls function as deterrent signals by causing ocelots to leave the area. Lastly, visual experiments show that sakis are able to discriminate dangerous from non-dangerous snakes and appear to adjust the intensity of their responses according threat level. This dissertation contributes the first systematic and experimental data on risk perception, anti-predator behaviors, and alarm call usage in Pithecia rylandsi, a little-known pitheciine species. Furthermore, this is the first experimental evidence using playbacks to show that wild ambush predators in naturalistic conditions are deterred by prey alarm calls. By incorporating data on both primate responses to predator stimuli and predator response to primate alarm calls, this research takes a rarely applied dual approach to the investigation of alarm call function. My findings also elucidate the need to more carefully consider the effects of sensory mode on primate anti-predator responses.