Quantifying animal movements is necessary for answering a wide array of research questions in ecology and conservation biology. Consequently, ecologists have made considerable efforts to identify the best way to estimate an animal’s home range, and many methods of estimating home ranges have arisen over the past half century. Most of these methods fall into two distinct categories of estimators that have only recently been described in statistical detail: those that measure range distributions (methods such as Kernel Density Estimation that quantify the long-run behavior of a movement process that features restricted space use) and those that measure occurrence distributions (methods such as Brownian Bridge Movement Models and the Correlated Random Walk Library that quantify uncertainty in an animal movement path during a specific period of observation). In this paper, we use theory, simulations, and empirical analysis to demonstrate the importance of applying these two classes of space use estimators appropriately and distinctly. Conflating range and occurrence distributions can have serious consequences for ecological inference and conservation practice. For example, in most situations, home-range estimates quantified using occurrence estimators are too small, and this problem is exacerbated by ongoing improvements in tracking technology that enable more frequent and more accurate data on animal movements. We encourage researchers to use range estimators to estimate the area of home ranges and occurrence estimators to answer other questions in movement ecology, such as when and where an animal crosses a linear feature, visits a location of interest, or interacts with other animals. Open Research Statement Tracking data on Aepyceros melampus, Beatragus hunteri, Bycanistes bucinator, Cerdocyon thous, Eulemur rufifrons, Glyptemys insculpta, Gyps coprotheres, Madoqua guentheri, Ovis canadensis, Propithecus verreauxi, Sus scrofa, and Ursus arctos are publicly archived in the Dryad repository (Noonan et al. 2018; https://doi.org/10.5061/dryad.v5051j2), as are data from Procapra gutturosa (Fleming et al. 2014a; https://doi.org/10.5061/dryad.45157). Data on Panthera onca were taken from (Morato et al. 2018). Additional data are publicly archived in the Movebank repository under the following identifiers: Canis latrans, 8159699; Canis lupus, 8159399; Chrysocyon brachyurus, 18156143; Felis silvestris, 40386102; Gyps africanus, 2919708; Lepus europaeus, 25727477; Martes pennanti, 2964494; Panthera leo, 220229; Papio cynocephalus, 222027; Syncerus caffer, 1764627; Tapirus terrestris, 443607536; Torgos tracheliotus, 2919708; and Ursus americanus, 8170674.

Historically, it was widely assumed that males dominate females socially in most mammals. However, recent studies revealed significant variation within and among species, opening new possibilities to explore the extent and drivers of sex biases in dominance relations. This study uses quantitative data from 253 populations across 121 primate species to investigate the distribution of, and factors associated with, sex biases in the outcome of male-female contests. We first showed that male-female contests are common (around half of all contests) and that males win >90% of these contests in less than 20% of populations. We next tested five hypotheses to explain sex biases in dominance relations. We found that female-biased dominance primarily occurs in primate societies where females have substantial reproductive control, as in monogamous, sexually monomorphic, and arboreal species. Female-biased dominance is also frequent in societies where female-female competition is intense, as in solitary or pair-living species where females are intolerant of each other, as well as in species where females face lower reproductive costs and are philopatric. Conversely, male-biased dominance is common in polygynous, dimorphic, terrestrial, and group-living species and often relies on physical superiority. In contrast, female empowerment hinges on alternative strategies, such as leveraging reproductive control. Our study highlights that male-female dominance relationships are highly variable and identifies the traits associated with the emergence of female- versus male-biased dominance in primate evolutionary history, which may also deepen our understanding of the origins of gender roles in early human societies.

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.

The 'social complexity hypothesis for communicative complexity' (SCHCC) suggests that greater social complexity promotes greater communicative complexity. This is because there is increased uncertainty in larger social groups with differentiated social interactions, providing an advantage for more diverse and more flexible signals to transfer diverse messages and to manage the behaviour of others. In this study, we offer a comprehensive approach to contrast the multimodal communicative systems of two closely related true lemur species having similar morphology and ecology but different social systems. We collected behavioural and acoustic data on 13 wild adult red-fronted lemurs, Eulemur rufifrons, belonging to three different groups, and 10 wild adult mongoose lemurs, E. mongoz, belonging to four different groups, in the Kirindy and Ankatsabe forests, respectively. We describe a new analytical framework to assess the complexity of signalling systems across modalities. Applying a multimodal approach may help uncover the different selective pressures acting on the communicative system and better understand adaptive functions that might not be obvious from the isolated study of its components. The results support the prediction of a more complex communicative system in E. rufifrons, which has a more complex social system than E. mongoz. E. rufifrons exhibited larger signalling repertoires, greater signalling rates, a greater number of signal combinations and a significantly lower level of predictability in its signalling network compared to E. mongoz. We discuss the differences in the communicative systems of the two species and the potential functions associated with nonhomologous signals. We further explore potential evolutionary pathways at the communicative system level and discuss the proposed framework's advantages and limitations at a cross-taxonomic scale. (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 license (http://creativecommons.org/licenses/ by/4.0/).

Many nocturnal mammals spend the day in nests or other shelters, but this aspect of their social organization remains obscure, despite interesting variation among species, seasons and individuals in whether they also sleep alone or in association with conspecifics. To contribute new comparative data on this neglected aspect of sociality, we monitored the occurrence, structure and stability of sleeping associations of 329 wild nocturnal gray mouse lemurs (Microcebus murinus) in artificial nests across four years. We found that most of these small primates slept in association with 1–8 other individuals, but virtually never with members of the opposite sex. A third of the individuals always exhibited the same sleeping tactic (20

Advances in computer vision as well as increasingly widespread video-based behavioral monitoring have great potential for transforming how we study animal cognition and behavior. However, there is still a fairly large gap between the exciting prospects and what can actually be achieved in practice today, especially in videos from the wild. With this perspective paper, we want to contribute towards closing this gap, by guiding behavioral scientists in what can be expected from current methods and steering computer vision researchers towards problems that are relevant to advance research in animal behavior. We start with a survey of the state-of-the-art methods for computer vision problems that are directly relevant to the video-based study of animal behavior, including object detection, multi-individual tracking, (inter)action recognition and individual identification. We then review methods for effort-efficient learning, which is one of the biggest challenges from a practical perspective. Finally, we close with an outlook into the future of the emerging field of computer vision for animal behavior, where we argue that the field should move fast beyond the common frame-by-frame processing and treat video as a first-class citizen.

In many animal species, cognitive abilities are under strong natural selection because decisions about foraging, habitat choice and predator avoidance affect fecundity and survival. But how has sexual selection, which is usually stronger on males than females, shaped the evolution of cognitive abilities that influence success when competing for mates or fertilizations? We aimed to investigate potential links between individual differences in male cognitive performance to variation in paternity arising solely from sexual selection. We therefore ran four standard cognitive assays to quantify five measures of cognitive performance by male mosquitofish (Gambusia holbrooki). Males were then assigned to 11 outdoor ponds where they could compete for females. Females mate many times, which leads to intense sperm competition and broods with mixed paternity. We genotyped 2,430 offspring to identify their fathers. Males with greater inhibitory control and better spatial learning abilities sired significantly more offspring, while males with better initial impulse control sired significantly fewer offspring. Associative and reversal learning did not predict a male's share of paternity. In sum, there was sexual selection on several, but not all, aspects of male cognitive performance.

Mammalian species with slow life histories invest heavily in offspring care to meet offspring nutritional and developmental requirements, typically at significant costs to mothers. While maternal care has been extensively studied, understanding the mechanisms driving variation in mother‒offspring relationships during key offspring developmental periods require more comparative data from natural populations. Using eight years of behavioral data, we analyzed mother-offspring interactions in 68 infants born to 46 mothers in wild mandrills (Mandrillus sphinx), spanning multiple birth cohorts and the entire first year of infant life, a critical period for individual social and physical development. We found that mothers dynamically adjusted caregiving behavior as infants aged, reducing physical contact while promoting spatial independence and social integration. Maternal traits, such as age, social rank, and reproductive history, shaped maternal phenotypes: high-ranking mothers promoted infant socialization while reducing carrying, and older, multiparous mothers invested more in grooming and physical contact than younger, inexperienced females. Previous infant loss predicted reduced maternal aggression, potentially due to fewer immatures to care for or behavioral adjustments aimed at improving offspring survival. Finally, mothers fostered closer bonds with their daughters while encouraging their sons’ independence, possibly resulting in more frequent tantrums observed in males. This sex-biased pattern likely reflects preparation for contrasting life histories between the sexes in this species. By combining extensive longitudinal observations with fine-scale, individual analyses, our study emphasizes the dynamic and multifaceted nature of early mother-offspring interactions and their evolutionary implications in long-lived mammals. Caring for offspring is energetically costly, requiring mothers to balance their own condition with their infants’ needs through flexible behaviors that can also have long-term consequences for offspring development and survival. Using eight years of data on wild mandrills, our study revealed how maternal traits such as age, rank, and reproductive history influence caregiving behavior during the first year of the infant’s life. Notably, high-ranking and experienced mothers facilitated their infants’ social engagement while fostering independence. The closer bonds observed with daughters and the greater independence encouraged in sons may reflect preparation for their contrasting adult roles (i.e., female philopatry and male natal dispersal). These findings deepen our understanding of the flexibility and evolutionary drivers of maternal care in long-lived mammals, highlighting the complex interplay between maternal behavior, infant needs, and future reproductive success.

Lemurs are often cited as an example of adaptive radiation, as more than 100 extant species have evolved and filled ecological niches on Madagascar. However, recent work suggests that lemurs lack a hallmark of other adaptive radiations: explosive speciation rates that decline over time. Thus, characterizing the tempo and mode of evolution in lemurs can reveal alternative ways that hyperdiverse clades arise over time, which might differ from traditional models. We explore lemur evolution using a phylogenomic dataset with broad taxonomic sampling that includes the lorisiforms of Asia and continental Africa. Our analyses reveal multiple bursts of diversification (without subsequent declines) that explain much of today's lemur diversity. We also find higher rates of speciation in Madagascar's lemurs compared to lorisiforms, and we demonstrate that the lemur clades with high diversification rates also have high rates of genomic introgression. This suggests that hybridization in these primates is not an evolutionary dead-end, but potential fuel for diversification. Considering the conservation crisis affecting strepsirrhine primates, with approximately 95% of species threatened with extinction, this study offers a perspective for explaining Madagascar's primate diversity and reveals patterns of speciation, extinction, and gene flow that will help inform future conservation decisions.

Wild animals face numerous challenges in less ideal habitats, including the lack of food as well as changes in diet. Understanding how the gut microbiomes of wild animals adapt to changes in food resources within suboptimal habitats is critical for their survival. Therefore, we conducted a longitudinal sampling of three gibbon species living in high-quality (Nomascus hainanus) and suboptimal (Nomascus concolor and Hoolock tianxing) habitats to address the dynamics of gut microbiome assembly over one year. The three gibbon species exhibited significantly different gut microbial diversity and composition. N. hainanus showed the lowest alpha diversity and highest nestedness, suggesting a more specialized and potentially stable microbial community in terms of composition, while H. tianxing displayed high species turnover and low nestedness, reflecting a more dynamic microbial ecosystem, which may indicate greater sensitivity to environmental changes or a flexible response to habitat variability. The gut microbial community of N. concolor was influenced by homogeneous selection in the deterministic process, primarily driven by Prevotellaceae. In contrast, the gut microbial communities of H. tianxing and N. hainanus were influenced by dispersal limitation in the stochastic process, driven by Acholeplasmataceae and Fibrobacterota, respectively. Further, the microbial response patterns to leaf feeding in N. hainanus differed from those of the other two gibbon species. In conclusion, this first cross-species comparative study provides initial insights into the different ecological adaptive strategies of gut microbiomes from a point of community assembly, which could contribute to the long-term conservation of wild primates.In this study, we conducted longitudinal sampling of three gibbon species living in high-quality (Nomascus hainanus) and suboptimal (Nomascus concolor and Hoolock tianxing) habitats to address the dynamics of gut microbiome (composition, alpha diversity, beta diversity and assembly process) over one year.

Most mammals, including humans, exhibit even or slightly male-biased birth sex ratios (BSRs) and female-biased adult sex ratios (ASRs) much later in life due to higher male mortality rates. The group-living primates of Madagascar are unusual in this respect because they lack female-biased ASRs, but it is unknown whether this is the result of skewed BSRs or sex-specific disappearance patterns. Using long-term demographic data from wild red-fronted lemurs ( Eulemur rufifrons ), we analysed their sex ratio dynamics across the lifespan. We assessed BSR via prenatal sex determination using maternal faecal oestrogen metabolite measurements during late pregnancy, confirming a visually determined equal sex ratio three months after birth, and indicating no early sex-specific mortality. Demographic analyses additionally disclosed higher female disappearance within the first 8 years of age, likely associated with reproductive effort early in life. Thereby, adult male survival had the greatest positive effect on the ASR. Our study offers a rare perspective on the dynamics of age- and sex-specific disappearance in a wild primate population, whose sex-reversed patterns may also contribute to a more general understanding of the mechanisms generating sex-biased mortality.

Infant survival is an important component of parental fitness in iteroparous species with slow life histories. From the infant's perspective, survival can be more or less directly influenced by the social environment, with group members potentially representing either a threat or a buffer against external stressors. Therefore, studying social relationship patterns during early development may provide insights into the effect of social factors on infant survival. To understand how group members interact with infants, and whether social relationships change due to the presence of infants, we conducted focal behavioral observations on four groups of wild redfronted lemurs (Eulemur rufifrons) during the birth season. Infant handling consisted mostly of grooming, while aggressive infant handling behaviors and allomaternal care occurred very rarely. Infants were groomed by individuals of all age-sex classes at similar rates except for a trend of higher infant handling rates in juvenile females. After giving birth, mothers received more approaches and were closer in proximity to other group members than before birth, but there were no changes in grooming rates of mothers and other group members. Mothers also initiated more aggressive interactions towards other group members after giving birth. Therefore, other redfronted lemurs were clearly attracted to infants, which caused changes in affinitive relationships of mothers. At the same time, the increase in maternal aggression indicates that group members also represent some threat to infants. Our study provides a starting point for future studies, exploring how these early infant handling interactions and the mother's relationships impact an infant's subsequent survival, development and future relationships.

In humans, frailty, risk-taking behaviors, and unhealthy lifestyles have been linked to shifts in adult sex ratios (ASR), which are heavily female-biased at older ages. Conversely, Madagascar's group-living primates frequently exhibit male-biased ASRs, defying patterns commonly observed among polygynous mammals. To explore these unusual sex ratio dynamics in wild redfronted lemurs (Eulemur rufifrons), we examined three behavioral proxies of mortality risk. We conducted 150 flight initiation distance (FID) experiments to assess sex differences in risk-taking and collected locomotion and proximity data to gauge variation in frailty and social integration. To achieve the observed male-biased ASR, we expected females to be less physically active than males, to have shorter FIDs, and to maintain less proximity to group members, thereby increasing their risk of predation. Using observational data from six years, we found that males spent less time being physically active than females. Locomotor quality followed an inverted U-shaped pattern, with very young individuals and those over eight years jumping less far than young adults. Older lemurs also had fewer nearby individuals. Individual FIDs decreased with height above the ground. Moreover, females with longer FIDs had a slightly lower risk of disappearing sooner, indicating a relevant behavioral adaptation that may enhance survival. However, weak evidence for sex differences in these proxies suggests that other intrinsic and extrinsic factors more strongly shape mortality and ASR in this species. The predicted effects of risk-taking, agility and social integration on survival therefore merit further study in additional taxa and using alternative proxies.

Social interactions are crucial for individual health and ultimately fitness, making the choice of social partners particularly important. Previous research has shown that individuals who succeed in foraging tasks often receive increased affiliation from group members. Similarly, in a social learning context, individuals who possess valuable information become more attractive social partners. Thus, an individual’s role in a foraging context–specifically, whether it is a successful producer–can influence its social relationships. Therefore, we examined the interplay between social learning, producing and scrounging behavior, and social relationships in four groups of wild redfronted lemurs ( Eulemur rufifrons ). We conducted an open diffusion experiment with food boxes that required animals to learn one of two techniques to open them. 27 out of 29 individuals participated in the experiment, 24 interacted with the boxes and 16 learned to open them. Initial success was better predicted by use of individual than social information, i.e., manipulating the food boxes vs. time spent watching successful individuals or scrounging. Older males were less successful than females. Scrounging occurred in about 26% of events, with on average 1.3 individuals scrounging. The technique used, age and sex of the producer did not predict scrounging frequency. Learners and males scrounged more often than non-learners and females. Among learners, less successful individuals scrounged more often and this effect was more pronounced in males. More successful individuals and those that were scrounged more often received more affiliative behavior. Thus, cognitive skills and scrounging tolerance may strengthen social relationships in this primate species. ### Competing Interest Statement The authors have declared no competing interest. Deutsche Forschungsgemeinschaft, https://ror.org/018mejw64, Project-ID 454648639 - SFB 1528 – Project B06

Intraspecific competition with fellow group members represents an unavoidable cost of group living. However, the causes of competition can vary among group members, and ecological and reproductive challenges faced by individuals throughout the year can trigger physical conflicts and or physiological responses. To date, few studies in mammals have described both physiological and behavioral responses to competition simultaneously across the year in both males and females. However, such an approach may shed light on ultimate drivers of sex-specific competitive strategies. In this six-year study on multiple groups of wild redfronted lemurs (Eulemur rufifrons), a primate species from Madagascar, we intended to identify the relative importance of feeding vs. reproductive competition for both sexes. We combined data on fecal glucocorticoid metabolite (FGCM) levels, a proxy for the physiological stress response, with behavioral observations on agonistic interactions during ecologically and socially challenging phases across the year. We found that while FGCM levels increased in both sexes with decreasing fruit consumption, this increase was not accompanied by concomitant changes in agonistic behavior. Female aggression and FGCM levels instead peaked during the birth season, while for males, aggression remained fairly constant across the year. Our results suggest that redfronted lemurs have mechanisms to avoid direct competition through aggression at times when individuals may need to conserve energy.

Detection and tracking of animals is an important first step for automated behavioral studies on videos. Nowadays, animal tracking is mostly done using deep learning frameworks based on keypoints, which show remarkable results in lab settings with fixed cameras, backgrounds and lighting. In contrast, multi-animal tracking in the wild is currently underexplored as it presents numerous challenges such as high background variability, lighting conditions, complex motion, and occlusion. We propose a multi-animal tracking model, PriMAT, for non-human primates in the wild. The model learns to detect and track primates and other objects of interest from labeled videos or single images using bounding boxes instead of keypoints. Using bounding boxes facilitates data annotation significantly and allows for more robust results. Our one-stage model is conceptually simple but highly flexible, and we add a classification branch that allows us to train individual identification. To evaluate the performance of our model, we apply it in two case studies with Assamese macaques and redfronted lemurs in the wild. We show that with only a few hundred frames labeled with bounding boxes, we can achieve robust tracking results. Combining these results with the classification branch, our model shows an accuracy of 83% when predicting lemur identities. Our approach presents a promising solution for accurately tracking and identifying animals in the wild using deep learning based bounding box tracking, offering researchers a tool to study animal behavior in their natural habitats. Our code, models, training images, and evaluation video sequences are publicly available, facilitating its use for animal behavior analyses and future research in this field. ### Competing Interest Statement The authors have declared no competing interest.

Wildlife tagging provides critical insights into animal movement ecology, physiology, and behavior amid global ecosystem changes. However, the stress induced by capture, handling, and tagging can impact post-release locomotion and activity and, consequently, the interpretation of study results. Here, we analyze post-tagging effects on 1585 individuals of 42 terrestrial mammal species using collar-collected GPS and accelerometer data. Species-specific displacements and overall dynamic body acceleration, as a proxy for activity, were assessed over 20days post-release to quantify disturbance intensity, recovery duration, and speed. Differences were evaluated, considering species-specific traits and the human footprint of the study region. Over 70% of the analyzed species exhibited significant behavioral changes following collaring events. Herbivores traveled farther with variable activity reactions, while omnivores and carnivores were initially less active and mobile. Recovery duration proved brief, with alterations diminishing within 4-7 tracking days for most species. Herbivores, particularly males, showed quicker displacement recovery (4 days) but slower activity recovery (7 days). Individuals in high human footprint areas displayed faster recovery, indicating adaptation to human disturbance. Our findings emphasize the necessity of extending tracking periods beyond 1 week and particular caution in remote study areas or herbivore-focused research, specifically in smaller mammals.

Gray mouse lemur, Microcebus murinus, mothers either cooperatively breed plurally with kin or breed solitarily. We describe the first observations of cooperative and solitary mobbing to defend offspring by wild cooperative breeding gray mouse lemur mothers in Kirindy Forest, Western Madagascar. We observed four groups of cooperatively breeding mothers and their offspring daily between 18:00 and 04:00 from January 1 to 15, 2023. Cooperative mobbing was observed twice, and solitary mobbing by a single cooperative breeding mother was observed once. There was one Malagasy tree boa, Sanzinia madagascariensis, per mobbing event. Mothers solitarily mobbed by directly approaching within 1 m of the boa, walking and changing distance while within 1 m of the boa. In addition to the solitary mobbing behaviors, cooperatively mobbing mothers approached the boa together from the same or different directions or alternated, and they gathered around the boa. Mothers collaborated in the context of offspring defense from predators and performed different complementary tasks: mobbing while another provided alloparental care by guarding the offspring of the association, that is, babysitting. Mothers performed similar mobbing behaviors and occasionally synchronized in time or coordinate in time and in space to approach from different directions and gather around the boa. Mothers did not come in contact with the boas during mobbing but kept a distance of at least 20 cm. On two mobbing events, the boa rose up with its head facing the mobbing mothers and climbed down the tree after the mobbing. Cooperative mobbing to defend offspring likely evolved by kin selection but reciprocity and an interaction between kin selection and reciprocity cannot be ruled out, since gray mouse lemur mothers cooperatively breed with kin and basically allonurse reciprocally.