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ABSTRACT: Fear of predation is a universal motivator. Because predators hunt using stealth and surprise, there is a widespread ability among prey to assess risk from chemical information – scents – in their environment. Consequently, scents often act as particularly strong modulators of memory and emotions. Recent advances in ecological research and analytical technology are leading to novel ways to use this chemical information to create effective attractants, repellents and anti‐anxiolytic compounds for wildlife managers, conservation biologists and health practitioners. However, there is extensive variation in the design, results, and interpretation of studies of olfactory‐based risk discrimination. To understand the highly variable literature in this area, we adopt a multi‐disciplinary approach and synthesize the latest findings from neurobiology, chemical ecology, and ethology to propose a contemporary framework that accounts for such disparate factors as the time‐limited stability of chemicals, highly canalized mechanisms that influence prey responses, and the context within which these scents are detected (e.g. availability of alternative resources, perceived shelter, and ambient physical parameters). This framework helps to account for the wide range of reported responses by prey to predator scents, and explains, paradoxically, how the same individual predator scent can be interpreted as either safe or dangerous to a prey animal depending on how, when and where the cue was deposited. We provide a hypothetical example to illustrate the most common factors that influence how a predator scent (from dingoes, Canis dingo) may both attract and repel the same target organism (kangaroos, Macropus spp.). This framework identifies the catalysts that enable dynamic scents, odours or odorants to be used as attractants as well as deterrents. Because effective scent tools often relate to traumatic memories (fear and/or anxiety) that cause future avoidance, this information may also guide the development of appeasement, enrichment and anti‐anxiolytic compounds, and help explain the observed variation in post‐traumatic‐related behaviours (including post‐traumatic stress disorder, PTSD) among diverse terrestrial taxa, including humans. [ABSTRACT FROM AUTHOR]

Living under predation risk may alter both behaviour and physiology of potential prey. In extreme cases, such alterations may have serious demographic consequences, and recent studies support that non-lethal effects of predation may have broad ecological consequences. However, behavioural and physiological responses to predation risk may be related to trade-offs associated with resource acquisition and direct predation risk. We validated an enzyme-linked immunoassay ( EIA) for non-invasive monitoring of stress in plains zebras ( Equus quagga) from faecal material. We used this assay in combination with behavioural data to assess if plains zebras living with and without lions ( Panthera leo) in a mountain savannah in southern Africa differed in behaviour and physiology, and if such differences were influenced by seasons with contrasting resource availability. Zebra group sizes did not differ between areas with and without lions, but zebra groups had more juveniles in an area with lions than groups in an area without lions, but only during the wet season. Similarly, we observed differences in individual vigilance, foraging behaviour and stress hormone concentrations, but all these differences were influenced by seasons. Despite these seasonal influences, our study did not suggest that zebras in an area with lions spent a higher proportion of time being vigilant, a lower proportion of time foraging, or had higher stress hormone levels. Our results instead suggest that zebras' responses to lion presence were highly context dependent and the result of complex interactions between resource abundance and cues about predation risk. Because of the obvious ecological and evolutionary ramifications of such findings, we argue that further research is needed to define the spatial and temporal scales over which predators impose indirect effects on their prey. [ABSTRACT FROM AUTHOR]

In most mammalian species, mothers must protect offspring from multiple sources of risk. In Australia, feral horses, Equus ferus caballus , have naturalized in many ecosystems, and foals are at risk from both predation by dingoes and sexually selected infanticide by nonpaternal stallions. This study tested maternal responses to these two forms of risk: risk of predation through dingo call playbacks and infanticide risk through a comparison of maternal protectiveness of foals in single- and multistallion bands. Mares were more vigilant and spent more time close to foals in bands with multiple resident stallions, where there is a higher risk of infanticide, relative to bands with a single stallion. Dominant stallions spent more time close to foals following the dingo call playbacks, indicating that stallions may play an important role in detecting and protecting foals from interspecific sources of risk. There was no significant increase in maternal protectiveness in response to dingo call playbacks, indicating that mares did not perceive dingo calls to be an immediate threat to foals. While predators were present, infanticide risk appeared to be the most significant modifier of maternal behaviour in this study. • Mothers need to respond to different types of risks to protect offspring. • Mothers increase vigilance and protective behaviour when infanticide risk is higher. • Dingo calls did not modify maternal behaviour. • Mothers perceived nonpaternal stallions to be riskier than dingoes. • Dominant stallions spent more time close to foals following dingo call playbacks. [ABSTRACT FROM AUTHOR]