Reactive and pre-emptive spatial cohesion in a social primate

LaBarge, Laura R.; Allan, Andrew T. L.; Berman, Carol M.; Margulis, Susan W.; Hill, Russell A.

doi:10.1016/j.anbehav.2020.03.005

Cited by 13 publications

(17 citation statements)

References 74 publications

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“…Leopards may infrequently hunt samangos in this habitat compared with other available mammals (Williams et al 2018), but it is uncertain where they are most frequently encountered on the landscape compared with eagles that are encountered more frequently (LaBarge et al 2020a). From a prey animal's perspective, encounters with a potential predator should elicit a response (including freezing or other cryptic reactions) even if the predator itself is not engaged in an attack.…”

Section: Discussionmentioning

confidence: 99%

“…visual cues or alarm calls) (Pays et al 2013). General wariness or risk perceptions of group members might influence how much of a group is monitoring the environment versus engaged in other activities (Hochman and Kotler 2007) or how close individuals are to their conspecifics (Frechette et al 2014;LaBarge et al 2020a). Both factors are hypothesized to limit the ability of individuals to personally collect information about potential risks (Fernández-Juricic and Kacelnik 2004).…”

Section: Introductionmentioning

confidence: 99%

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Extent of threat detection depends on predator type and behavioral context in wild samango monkey groups

LaBarge

Allan

Berman

et al. 2021

Behav Ecol Sociobiol

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Detecting predators requires information, and many behavioral and environmental features are predicted to enhance or limit an animal's ability to learn about potential danger. Animals living in groups are thought to be at an advantage for learning about predator presence, but individual safety also depends on cues spreading from detectors to non-detectors as unsuspecting individuals may still be vulnerable. In this study we simulated predator presence among two groups of wild samango monkeys (Cercopithecus albogularis schwarzi) to mimic natural encounters where only some individuals within a primate social group have access to personal information about potential threats. We did this using visual models of natural predators placed in positions for the monkeys to encounter within the landscape for a limited amount of time. We measured the number of individuals that were observed to detect and respond to these models with antipredator reactions, relative to subgroup size. While initial detectors that were able to spot the model themselves always reacted with overt behaviors such as alarm calling or staring at the model, responses did not typically spread to all group members. The number of initial detectors was also only weakly associated with the number of individuals that responded at the end of a trial. Initial responses to leopards were much stronger and more likely to spread than those given in response to pythons or eagles and the importance of behaviors assumed to have an antipredator function depended on the type of predator the samangos encountered. Significance StatementEarly detection is critical for prey to survive an encounter with an ambush predator. Social prey have the advantage of being able to rely on cues from conspecifics, though individuals that do not detect a potential threat can still be susceptible to attack. Here we exposed wild samango monkeys to predator models to simulate predator presence to only part of a social group. Habitat visibility was a key predictor affecting collective detection, but the importance of other hypothesized factors-scanning and group spatial cohesion depended on the predator species. Overall, our results indicate that the social effectiveness of purported risk-sensitive strategies varies based on the type of threat encountered.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Extent of threat detection depends on predator type and behavioral context in wild samango monkey groups

LaBarge

Allan

Berman

et al. 2021

Behav Ecol Sociobiol

Self Cite

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“…Samango monkeys may therefore modify their behavior at a given location based on the spatial memory of previous encounters. A recent study from our field site by LaBarge et al (2020) would appear to support this hypothesis, as they found that samangos pre-emptively increased spatial cohesion in response to eagle encounter risk. Our findings corroborate those of LaBarge et al (2020), albeit over a longer study period, and suggest that samango monkeys may overestimate risk in areas perceived as high risk and opt to "play it safe" by reducing neighbor distance in these areas (Bouskila & Blumstein, 1992).…”

Section: Discussionmentioning

confidence: 72%

Behavioral responses to spatial variation in perceived predation risk and resource availability in an arboreal primate

2022

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Prey species must often face a trade-off between acquiring resources and minimizing predation risk. The spatial variation in predation risk across a landscape, as perceived by prey across their foraging or home range, creates a "landscape of fear" by which individuals modify their behavior in response to the level of perceived risk. Here, we explored the influence of perceived predation risk, habitat features associated with risk, and fruit availability, on the spatial variation in behavior of the endangered forest-dwelling samango monkey (Cercopithecus albogularis schwarzi). We collected behavioral and location data on two habituated samango monkey groups in the Soutpansberg Mountains, South Africa, between 2012 and 2016. We further collected location data of the samango monkey's acoustically distinct alarm call, which has an unambiguous association with aerial predators, to spatially map perceived risk across the landscape. Using generalized linear mixed models, we found that perceived risk from eagles significantly influenced the spatial distribution of critical life-functioning behaviors, with samango monkeys increasing feeding and foraging in high-risk areas. To mitigate this risk, samangos increased cohesion between group members, which subsequently reduced vigilance levels. Group cohesion further increased in high-risk areas with abundant fruit, relative to high-risk, fruit-poor areas, demonstrating the monkey's foraging/risk trade-off. Feeding was also reduced in areas of low canopy height, while vigilance decreased with increasing understory visibility and distance from sleep site, showing the influence of landscape features on risk perception from other predator guilds. Thus, for arboreal species foraging in a 3-D landscape, risk perception may occur at multiple scales and in response to multiple predator guilds. Only moving was influenced by fruit availability, either due to moving between localized food patches or from escaping high-risk areas following feeding bouts. These findings highlight that risk-taking in samango monkeys is only associated with behaviors fundamental to survival at a given

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“…Proximity between individuals may depend upon perceived levels of risk in the environment (LaBarge et al, 2020). From this perspective, the response of mountain gorillas to the presence and immediate proximity of tourists suggests that gorillas might perceive tourists as a risk.…”

Section: Discussionmentioning

confidence: 99%

Mountain Gorillas benefit from social distancing too: Close proximity from tourists affects gorillas sociality

Costa¹,

Romano²,

Pereira³

et al. 2022

Preprint

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Nature-based tourism supports the protection of the mountain gorilla ecosystem, benefiting humans and wildlife populations living therein. Therefore, assessing to what degree the presence and proximity of tourists affect wildlife is important to ensure long-term benefits and to avoid immediate costs, such as the increased risk of pathogen spillover. Because wild and less habituated animals might see human activities as stressors, we hypothesised that the increased presence and proximity of tourists leads to an immediate increase in mountain gorilla social cohesion. To test this hypothesis, we constructed gorilla social networks from association rates before, during and after tourist visits, and when tourists were very close (≤ 3m) or close (> 3m) to them. Our analysis focused on this small distance threshold (≤ 3m and > 3m) because the 7m rule enforced by the national park was violated 85% of the time; the data were therefore heavily unbalanced towards smaller distances. For each network, we calculated metrics that characterized different aspects of social cohesion and we investigated whether and how they differed across conditions. Our analysis showed that gorillas spent more time in closer association after tourists arrived and when they were in very close proximity (< 3m away) to them. Immediate changes were detected in the number of individuals close to each other, the time they spent together and the distance of an individual to all other individuals. At the ultimate level, gorillas might increase social cohesion because they perceive tourists as a risk. At the proximate level, this behaviour might be driven by social buffering. These results highlight the need to enforce the original tourism regulations (i.e., maximum of 8 people per group, including park staff, and keeping a minimum distance of 7m). This will promote human and wildlife wellbeing, while ensuring the continued success of mountain gorilla tourism.

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Reactive and pre-emptive spatial cohesion in a social primate

Cited by 13 publications

References 74 publications

Extent of threat detection depends on predator type and behavioral context in wild samango monkey groups

Extent of threat detection depends on predator type and behavioral context in wild samango monkey groups

Behavioral responses to spatial variation in perceived predation risk and resource availability in an arboreal primate

Mountain Gorillas benefit from social distancing too: Close proximity from tourists affects gorillas sociality

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