Model vs. playback experiments: The impact of sensory mode on predator‐specific escape responses in saki monkeys

Abstract

Although experimentally simulating predator presence helps improve sample sizes in studies of free‐ranging animals, few studies have examined whether auditory playbacks and visual models produce similar results. Additionally, it is unclear if anti‐predator strategies are specific to predator hunting styles in understudied Neotropical pitheciid primates, limiting what we can generalize about this phenomenon across this taxonomic order. We conducted predator simulation experiments to assess whether wild Rylands' bald‐faced saki monkeys (Pithecia rylandsi) recognize predators based solely on acoustic cues, exhibit predator‐specific responses to different predator types, and vary responses to presentations in different sensory modes. In our playback experiments, sakis had weak responses to non‐predator control vocalizations compared to jaguar growls and harpy eagle shrieks. In most predator playbacks, subjects' first glance corresponded to the direction from which simulated predators would typically attack (above vs. below). However, although sakis exhibited appropriate movement responses to harpy playbacks (i.e., descending canopy), they exhibited no clear movement patterns when presented with jaguar playbacks. In contrast, jaguar model experiments consistently elicited fast approaches, mobbing‐style responses, and long alarm calling bouts. Thus, if we had relied on playbacks alone, we might have concluded that sakis have only generalized responses to terrestrial ambush predators. In fact, in all variables measured (e.g., latency, number of calls, and response duration), models of both predator species elicited stronger reactions than playbacks. Results indicate that bald‐faced sakis can identify predators based solely on vocalizations, but do not exhibit predator‐specific escape responses to terrestrial predators based on acoustic cues alone. The differential response to playbacks and models calls into question the reliability of using acoustic‐only stimuli to assess the specificity of anti‐predator behavior to predator hunting styles in some primate species.

Impact of predator model presentation paradigms on titi monkey alarm sequences

“…In other words, titi monkeys exhibited a similar vocal reaction to raptor playback and raptor model presentations, but their reaction to playbacks of felids was different to that to felid models. This is congruent with the study of Adams and Kitchen ( 2020 ), which showed that behavioural reaction of saki monkeys varied with the exposure paradigm for jaguar, but not for harpy eagles. Several hypotheses can be put forward to explain our results.…”

“…It can be argued that the lack of vocal response (cluster 1) is a cryptic strategy, but the fact that, in some trials, groups responded with a vocal reaction also given to raptors (clusters 2, 3 and 4) does not support this idea. It can also be argued that titi monkeys do not react in a predator-specific way to felid playbacks because, since these predators can attack both from the ground and the canopy, acoustic cues leave the monkeys with little information about the location of the threat, and hence, the appropriate reaction to adopt is not straightforward (Adams and Kitchen 2020 ). This hypothesis does not apply here, for predator calls were broadcasted from distinct locations (ground or canopy) that left little room for life-threatening uncertainty about the predator’s location.…”

Response of diademed sifaka (Propithecus diadema) to fosa (Cryptoprocta ferox) predation in the Betampona Strict Nature Reserve, Madagascar

“…The Zzuss and Zzuss‐tsk appeared to serve as an alert for conspecifics which, potentially, disrupts the surprise effect of the predator and deters its continued pursuit of the prey (Woodland et al., 1980). The “pursuit deterrent” function (Woodland et al., 1980) has been suggested for alarm calls against predators with an ambush hunting strategy as given by red‐tailed sportive lemurs ( Lepilemur ruficaudatus ) (Fichtel, 2007), and monkey species of the genera Pithecia , Colobus , Cercopithecus , and Cercocebus against leopards and jaguars (Adams & Kitchen, 2020; Schel et al., 2010; Zuberbühler et al., 1999).…”

Temporary behavioral responses to playbacks by a pest parrot and implications for management

“…Moreover, acoustic cues have been used to address management problems for particularly problematic populations via broadcasting biologically relevant sounds to influence reproduction (e.g., bark beetles (Coleoptera: Curculionidae) (Hofstetter et al, 2014)) or using acoustic deterrents, such as underwater speakers, to influence movement (e.g., fish (Putland & Mensinger, 2019)). More generally, acoustic cues have been used to investigate behaviors such as territoriality (Frostman & Sherman, 2004;Heinsohn, 1997;Reif et al, 2015), vocal discrimination (Searcy, Nowicki, & Hughes, 1997;Searcy et al, 2002), and anti-predator responses (Adams & Kitchen, 2020;Bshary, 2001). With many species attuned to auditory cues for their ecology (e.g., primates (Ghazanfar & Santos, 2003), birds (Marler & Slabbekoorn, 2004)), auditory cues provide useful opportunities for nonlethal and widespread management strategies that may reduce human-wildlife conflict.…”