A variety of intrinsic and extrinsic factors shape an animal's antipredator behaviour. Flight initiation distance (FID) is a common way to evaluate antipredator behaviour and is used to assess an individual's shyness or boldness. Numerous FID studies, in a variety of taxa, have shown that FID is a decision that is sensitive to both the costs and benefits of flight. While there is some evidence that individuals may have repeatable FIDs, and there are several genes associated with FID (DRD4 and SERT), few studies have quantified the genetic variance of FID. Knowledge of genetic basis permits us to understand the evolutionary potential of a trait within a population, and heritable variation is yet another mechanism that enables animals to respond to a dynamically changing world. Here we conducted a variance decomposition analysis using the quantitative genetic mixed model (i.e. the 'animal model') to identify the degree to which genetic and nongenetic factors explained variation in FID within a population of wild yellow-bellied marmots, Marmota flaviventer. Within our 18-year data set of individually marked individuals, we found significant heritable variation for FID that we estimated at 0.15. These results demonstrate that genetics, in addition to environmental factors, influence an animal's fear response. Understanding evolvability and plasticity of FID could have important implications for conservation. (c) 2025 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights are reserved, including those for text and data mining, AI training, and similar technologies.

Responses of natural populations to climate change are driven by how multiple climatic and biotic factors affect survival and reproduction, and ultimately shape population dynamics. Yet, despite substantial progress in synthesizing the sensitivity of populations to climatic variation, comparative studies still overlook such complex interactions among drivers that generate variation in population-level metrics. Here, we use a common framework to synthesize how the joint effects of climate and biotic drivers on different vital rates impact population change, using unique long-term data from 41 species, ranging from trees to primates. We show that simultaneous effects of multiple climatic drivers exacerbate population responses to climate change, especially for fast-lived species. However, accounting for density feedbacks under climate variation buffers the effects of climate change on population dynamics. In all species considered in our analyses, such interactions between climate and density had starkly different effects depending on the age, size, or life-cycle stage of individuals, regardless of the life history of species. Our work provides the first general framework to assess how covarying effects of climate and density across a wide range of population models can impact populations of plants and animals under climate change.

Alarm calling is an important antipredator behaviour by which individuals alert conspecifics and heterospecifics of possible danger and/or ward off potential predators. The propensity to utter calls may reflect the amount of risk an individual experiences and a variety of other internal and environmental factors that may be context and species specific. However, whether the propensity to utter alarm calls is heritable has not been studied. Using a quantitative genetic animal model, we estimated the heritability of alarm calling in yellow-bellied marmots, Marmota flaviventer. We found significant heritability in the propensity to utter naturally elicited alarm calls (0.06) and trap-elicited alarm calls when marmots were trapped (0.21). There was a small but significant genetic correlation between these traits (0.338). Together, these results show that the propensity to utter alarm calls is individually variable and context dependent and can evolve in response to natural selection. (c) 2025 The Author(s). Published by Elsevier Ltd on behalf of The Association for the Study of Animal Behaviour. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/ licenses/by-nc-nd/4.0/).

Human recreation influences the diel activity of animals and elucidating these responses informs management of species of conservation concern. We studied how mountain lions (Puma concolor) persisting in greater Los Angeles, California, USA adjust diel activity patterns in response to spatial and temporal variation in human recreation by combining publicly available data on recreation with GPS telemetry and accelerometer data. Mountain lions reduced diurnal activity, shifted timing of dawn activity, and became more nocturnal in areas with high recreation. There were differences in temporal responses between the sexes that might reflect behavioral shifts by females to avoid potentially dangerous male conspecifics. We found no evidence that mountain lions modified their behavior based on differences in recreation between weekdays and the weekend. The lack of a weekend effect may be a function of mountain lions being mostly nocturnal, which may be sufficient to avoid most recreation regardless of intraweek variation. Mountain lions have persisted within greater Los Angeles despite being limited spatially in this human-dominated landscape. Our work suggests that mountain lions are also constrained temporally through shifts in their diel activity.

Ecotourism promises to reconcile wildlife conservation and human development if negative impacts of human visitation and associated infrastructure can be minimized. Animal behavior studies can be used to identify individual and population responses to anthropogenic impacts before other fitness consequences are documented. With input from professionals in animal behavior and ecotourism, we identified key questions needed to better understand the impact of ecotourism on wildlife. Activity budgets, foraging, movement, stress, habituation, and reproduction were themes that emerged from our survey. We highlight promising research on these themes and identify remaining behavioral research questions about conserving wildlife in the context of ecotourism. Although ecotourism activities often have detrimental effects on animal behavior, we highlight research needs that can inform management and ecotourist education to improve human behavior to be more compatible with sustainable use of nature.

The period before sexual maturity is a sensitive life stage where most development and change occur. Studies in humans and other animals show that early adverse experiences contribute to poor health and survival. However, the mechanisms are still unclear. Some have found that early life adversity (ELA) can lead to elevated glucocorticoids later in life, dysregulate the stress response, and increase the impact of later stressors. However, most animal studies have focused on individual stressors. Protecting wild populations that are exposed to multiple stressors requires a better understanding of the physiological consequences of several co-occurring stressors. We used a cumulative adversity index (CAI) to ask whether early adverse experiences were associated with increased levels of adult fecal glucocorticoid metabolites (FGM) in wild female yellow-bellied marmots (Marmota flaviventer). We found a significant interaction between adversity and elevation that explained variation in FGMs. Thus, we infer that ELA can modulate FGMs, but contrary to similar research in other mammals, the trend was toward downregulation under more environmentally relaxed conditions (lower elevation). Our results highlight the value of studying the relative importance of early and later stressors in the physiology of different wild taxa when investigating the mechanisms of early life adversity.

Group size can influence flight initiation distance (FID), a key antipredator behavior, in many animal species. In fishes, however, the effect of group size on FID remains unclear. Two different mechanisms might explain a putative relationship between group size and FID. If fish benefited from having more vigilant individuals around, we would expect group size to be positively associated with FID (considering collective vigilance in the context of the many eyes hypothesis). By contrast, if fish benefited from a predator dilution effect, we would expect group size to be negatively associated with FID. Importantly, such relationships should be critically sensitive to background risk levels. We capitalized on FID observations inside and outside marine protected areas and simulated risk by having a risky spearfisher or a non-risky snorkeler swim towards white seabream (Diplodus sargus) to estimate the relationship between FID and group size. Model selection provides weak evidence that group size positively influences FID of white seabream when group size was modelled two ways: categorically (alone vs. shoal), and continuously (range 2–15). While the results suggest that overall group size has a measurable impact on FID, the presence of spearfishers or snorkelers had a weak effect on the relationship of group size and FID, which seems to be more sensitive exclusively to the protection level (inside/outside marine protected areas). Our findings align with previous studies showing mixed results on the relationship between group size and FID. This study underscores the complexity of antipredator behaviors in natural settings and suggests that multiple interlinked factors, rather than group size alone, drive FID in fishes. Future research should integrate field observations, laboratory experiments, and modeling to study the ecological influence of group size on FID more comprehensively. The relationship between group size and flight initiation distance is a key component to understand predator-prey interactions in fishes, but empirical support for such relationship is mixed. We used an experimental system where the relationship between group size and flight initiation distance of an exploited fish is measured across a gradient of risk associated to underwater human presence (i.e., spearfishing/snorkeling and inside/outside marine protected areas). We found weak evidence for group size to influence flight-initiation distance in response to risk associated to underwater human presence; rather protection level seems to be the most important factor influencing it. These results highlight the complexity of studying antipredator behavior in fishes and underscores the need for integrative approaches (laboratory-field-modelling) to fully understand the ecological influence of group size in predator-prey dynamics.

Killing animals is a ubiquitous human activity consistent with our predatory and competitive ecological roles within the global food web. However, this reality does not automatically justify the moral permissibility of the various ways and reasons why humans kill animals – additional ethical arguments are required. Multiple ethical theories or frameworks provide guidance on this subject, and here we explore the permissibility of intentional animal killing within (1) consequentialism, (2) natural law or deontology, (3) religious ethics or divine command theory, (4) virtue ethics, (5) care ethics, (6) contractarianism or social contract theory, (7) ethical particularism, and (8) environmental ethics. These frameworks are most often used to argue that intentional animal killing is morally impermissible, bad, incorrect, or wrong, yet here we show that these same ethical frameworks can be used to argue that many forms of intentional animal killing are morally permissible, good, correct, or right. Each of these ethical frameworks support constrained positions where intentional animal killing is morally permissible in a variety of common contexts, and we further address and dispel typical ethical objections to this view. Given the demonstrably widespread and consistent ways that intentional animal killing can be ethically supported across multiple frameworks, we show that it is incorrect to label such killing as categorically unethical. We encourage deeper consideration of the many ethical arguments that support intentional animal killing and the contexts in which they apply.

As the global climate changes, temperatures are rising, snow is melting earlier, and rainfall is becoming more variable, and these climatic changes may create an ecological mismatch. While prior work has shown how animals respond to these changes physiologically and behaviorally, few have specifically investigated antipredator behavior, an essential activity. In many species, there are direct fitness tradeoffs between allocating time and energy to antipredator vigilance and foraging. To discover how these tradeoffs are affected by climate change, we studied how temperature, snowmelt date, and rainfall affected the proportion of time yellow-bellied marmots (Marmota flaviventer) allocated to vigilance during bouts of foraging. While snowmelt and temperature did not explain variation in vigilance, rainfall did. Higher rainfall in the week prior to a focal observation was associated with higher vigilance, possibly reflecting more abundant food that affords the luxury of increasing antipredator vigilance while foraging. Such an effect might be consequential at the population level given the importance of foraging and antipredator behaviors for a highly time restrictive hibernating species. Further research is necessary to determine consequences at the population level and whether and how these findings extend to other species.

Humans are often perceived as predators by free‐living animals, and thus, even non‐consumptive human activities such as outdoor recreation may trigger behavioural and physiological responses, often with negative consequences on individual fitness and population persistence. Nonetheless, there is growing evidence that wildlife can also have remarkable behavioural tolerance, but no clear picture has yet emerged regarding the mechanisms explaining different responses to humans. We investigated the effect of different types of human activity – hunting and outdoor recreation – on behavioural tolerance to humans in Alpine marmots Marmota marmota . Marmots were studied in areas with contrasting protection regimes and under different levels of outdoor recreation in northern Italy over three seasons (2021–2023). Flight initiation distance (i.e. the distance at which an animal escapes from an approaching person) was used as a proxy of tolerance to human disturbance and tested against levels of outdoor recreation and hunting using linear mixed modelling. Marmots were more sensitive to human disturbance in hunted as compared to protected areas, whereas we did not find evidence for changes in behavioural tolerance when exposed to varying levels of outdoor recreation. In turn, our study suggests that hunting, by reducing behavioural tolerance to humans, could exacerbate the negative effects of non‐lethal human activities on wildlife. This has implications for conservation and management strategies aimed at promoting coexistence in human‐altered landscapes.

How phenotypes are shaped by multilevel selection-the theoretical framework proposing natural selection occurs at more than one level of biological organization-is a classic debate in biology. Though social behaviours are a common theoretical example for multilevel selection, it is unknown if and how multilevel selection acts on sociality in the wild. We studied the relative strength of multilevel selection on both individual behaviour and group social structure, quantified with social networks and 19 years of data from a wild, free-living mammal, the yellow-bellied marmot (Marmota flaviventer). Contextual analysis (exploring the impact of individual and group social phenotypes on individual fitness, relative to each other) revealed multilevel selection gradients in specific fitness and life history contexts, with selection for group social structure being just as strong, if not stronger, than individual social behaviour. We also found antagonistic multilevel selection gradients within and between levels, potentially explaining why increased sociality is not as beneficial or heritable in this system compared with other social taxa. Thus, the evolutionary dynamics of hierarchical or nested biological traits should be assessed at multiple levels simultaneously to tell a more accurate and comprehensive story. Overall, we provide empirical evidence suggesting that multilevel selection acts on social relationships and structures in the wild and provide direct evidence for a classic, unanswered question in biology.

I review a case study of marmots that contributed to the empirical basis of the nonlinearity and fear hypothesis, which explains why certain nonlinear acoustic phenomena (NLP) are produced in extremely high-risk situations and communicate high urgency. In response to detecting predatory threats, yellow-bellied marmots (Marmota flaviventer) emit alarm calls and, in some situations, emit fear screams. Prior work on marmots has shown that call production is associated with the degree of risk the caller experiences and that they are individually distinctive. Receivers respond to calls and are sensitive to variation in caller reliability. Calls also contain nonlinear acoustic phenomena. Work has shown that socially isolated animals and those infected with Eimeria, an intestinal parasite, produced 'noisier' calls. However, animals that were likely under greater stress (as measured with faecal glucocorticoid metabolites) produced more structured and less noisy calls. The addition of NLP increases responsiveness in receivers. NLP in alarm calls have modest heritability. Taken together, the study of NLP in marmots has enhanced our understanding of the potential information encoded in alarm calls and is consistent with the hypothesis that variation in NLP production communicates fear, which stimulates work with other species, including humans.This article is part of the theme issue 'Nonlinear phenomena in vertebrate vocalizations: mechanisms and communicative functions'.

Yellow-bellied marmots, Marmota flaviventer, are facultatively social and may form multigenerational societies, which are characterized by individuals sharing and defending space, possessing the ability to distinguish group members from outsiders and potentially persisting for many generations. I review some 63 years of continuous study that has revealed a number of insights about the adaptive value of sociality and societies. Because of their facultative sociality and because we have studied social behaviour and societies a variety of different of ways over the years, this social variation makes it difficult to make simple summary statements about society structure and formation. None the less, this variation may make them a good system in which to study incipient society formation. (c) 2025 The Author(s). Published by Elsevier Ltd on behalf of The Association for the Study of Animal Behaviour. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/ licenses/by-nc-nd/4.0/).

One of the most explored factors mediating antipredator behavior is group size, which generally predicts individuals in larger social groups allocate less time to antipredator vigilance while foraging. However, group size alone does not capture the full complexity of sociality. An individual's 'sense of security', or their perceived risk of predation, is also influenced by an individual's social connections. Further, group social structure - the pattern of all social interactions in a group - could explain additional variation in perceptions of security for the individuals that reside in the group. Using the time allocated to vigilance during foraging and flight initiation distance (FID) to quantify individuals' social security, we explored whether individual yellow-bellied marmots (Marmota flaviventer) in tightly connected social groups looked less while foraging and had shorter FIDs. Using linear mixed effect models, we found modest support for the Social Security Hypothesis; individuals in more socially reciprocal groups may spend less time looking for predators while foraging. No measure of group social structure explained variation in FID. Measures of the immediate environment (the number of individuals within 10 m for vigilance and the distance from burrow and alert distance for FID) had effect sizes an order of magnitude greater than measures of social structure, suggesting an individual's immediate environment has more of an impact on their antipredator behavior than the structure of their social group.

Conservation is an evolving discipline, with its values changing over time. Animal welfare is gaining attention, but can conflict with other conservation values. We illustrate how different management decisions arise from prioritizing different values, and show how these conflicts can depend on value prioritization, as well as how values such as animal welfare are defined. This includes the limits (type of welfare states), scope (range of species), and timescales considered. Since small changes in value articulation and prioritization can lead to major changes in management decisions, we argue for making values and trade-offs explicit. An established structured decision-making (SDM) framework can enhance transparency, reducing misunderstanding in conservation controversies and helping maintain public trust in science.

Emitting alarm calls may be costly, but few studies have asked whether calling increases a caller's risk of predation and survival. Since observing animals calling and being killed is relatively rare, we capitalized on over 24,000 h of observations of marmot colonies and asked whether variation in the rate that yellow-bellied marmots (Marmota flaviventer) alarm called was associated with the probability of summer mortality, a proxy for predation. Using a generalized mixed model that controlled for factors that influenced the likelihood of survival, we found that marmots who called at higher rates were substantially more likely to die over the summer. Because virtually all summer mortality is due to predation, these results suggest that calling is indeed costly for marmots. Additionally, the results from a Cox survival analysis showed that marmots that called more lived significantly shorter lives. Prior studies have shown that marmots reduce the risk by emitting calls only when close to their burrows, but this newly quantified survival cost suggests a constraint on eliminating risks. Quantifying the cost of alarm calling using a similar approach in other systems will help us better understand its true costs, which is an essential value for theoretical models of calling and social behavior.

Consensus statements can be very influential in medicine and public health. Some of these statements use systematic evidence synthesis but others fail on this front. Many consensus statements use panels of experts to deduce perceived consensus through Delphi processes. We argue that stacking of panel members toward one particular position or narrative is a major threat, especially in absence of systematic evidence review. Stacking may involve financial conflicts of interest, but nonfinancial conflicts of strong advocacy can also cause major bias. Given their emerging importance, we describe here how such consensus statements may be misleading, by analyzing in depth a recent high-impact Delphi consensus statement on COVID-19 recommendations as a case example. We demonstrate that many of the selected panel members and at least 35% of the core panel members had advocated toward COVID-19 elimination (Zero-COVID) during the pandemic and were leading members of aggressive advocacy groups. These advocacy conflicts were not declared in the Delphi consensus publication, with rare exceptions. Therefore, we propose that consensus statements should always require rigorous evidence synthesis and maximal transparency on potential biases toward advocacy or lobbyist groups to be valid. While advocacy can have many important functions, its biased impact on consensus panels should be carefully avoided.

AbstractAnimals that are successful in urban habitats often have reduced antipredator responses toward people (sometimes called “fear” responses). However, few studies test whether sympatric species differ in their responses to humans, which may explain differing sensitivities to urbanization. Here, we quantified the behavioral and physiological responses to humans in two lizard species, side-blotched lizards (Uta stansburiana) and western fence lizards (Sceloporus occidentalis), across three different habitat types that vary in human impact: natural habitats with low levels of human activity, natural habitats with high levels of human activity, and urban habitats. We found that side-blotched lizards had longer flight initiation distances, were found closer to a refuge, and were more likely to hide than fence lizards, behaviors that could indicate greater fearfulness. Both lizard species were found closer to a refuge and were also more likely to hide in the urban habitat than in the natural habitat with low human impact, which could represent adaptive behaviors for increased risks in urban areas (e.g. cats). Western fence lizards exhibited lower body sizes and conditions in the habitats with moderate and high levels of human activity, whereas these traits did not differ among habitats in side-blotched lizards. Baseline and stress-induced corticosterone concentrations did not differ across habitats for both species, suggesting that human-impacted habitats were not stressful or that lizards had undergone habituation-like processes in these habitats. Taken together, our results highlight the importance of standardized measurements across multiple species in the same habitats to understand differential responses to human-induced environmental change.