Conventions can be defined as arbitrary and self-sustaining practices that emerge in a population and facilitate solving coordination problems. A recent study traced the formation of simple conventions in captive baboons in a touch-screen-based color-matching 'game'. We replicated this task with human pairs under different conditions (with/without visual access to the partner's screen; with/without prior information on the task structure) to assess their effects on the formation and stability of conventions. We found that more information delayed the formation of conventions (arbitrary rankings of colors that determined choices in any given color pairing). Analysis of self-reported strategies did not reveal a clear effect of condition on levels of elicited strategic behavior. Interestingly, pairs maintained their conventions even when given visual access to their partner's screen, despite the availability of an alternative, potentially simpler, cognitive strategy. In a follow-up variant of the task that paired up experienced subjects with a naïve partner, conventions emerged faster but did not replicate the color hierarchy convention of the experienced player, demonstrating the transmission of "know-how" but not "know-what" information. We discuss the implications of our results for understanding the cognitive mechanisms necessary to support the formation, maintenance, and transmission of conventions.

While enhanced decision-making in larger groups, known as the wisdom of crowds, has been demonstrated in controlled experimental conditions, the intractability of observing large-scale wild groups has limited the availability of evidence from natural systems. Addressing this challenge, we analyze migratory trajectories of flocks of thousands of wild songbirds extracted from 23 years of weather radar data across the Great Lakes of North America. We show that the wisdom of crowds emerged: Larger flocks oriented more accurately toward their population’s migratory direction than smaller flocks. This likely emerged through the many-wrongs effect, with individual errors averaged out across flocks. Furthermore, flock size declined over time, a trend that may erode navigational performance and carry important ecological implications amid anthropogenic population fragmentation. Together, these findings reveal how the wisdom of crowds emerges in natural systems and underscore its role in shaping movement and ecological resilience in social animals.

Abstract Collective movement requires coordination between individuals, yet how this emerges during early interactions remains poorly understood. We investigated how partner familiarity influences coordination, leader-follower dynamics, and learning in homing pigeon pairs navigating from novel sites. Birds were released repeatedly with either familiar or unfamiliar partners, followed by solo releases to assess learning. By quantifying bidirectional information flow, we found familiarity influenced information-transfer dynamics during the first release: familiar pairs exhibited more asymmetric information transfer, likely reflecting established leader-follower relationships, whereas unfamiliar pairs showed more symmetric exchange. These differences disappeared after one release. Conversely, familiarity had little effect on cohesion or navigational performance. There was some evidence for an influence on learning: birds from familiar pairings had higher homing efficiency on a subsequent solo release. Finally, across partnerships, followership was more predictable than leadership with respect to individual identity and flight speed, indicating stable variation in individuals’ tendency to follow rather than lead. This suggests that a shift in emphasis from leadership to followership might enhance our understanding of collective decision-making dynamics. Our results demonstrate how flight partners rapidly coordinate, producing limited downstream effects on navigation and learning, with implications for many animals that travel in fission-fusion transitory collectives.

Better decision-making in larger groups than smaller groups or individuals has been observed across various taxa. While this phenomenon is thought to result from the pooling of independent information in collective decision-making, an alternative mechanism is the better retention of learned information in larger groups: collective memory. We investigated the emergence of collective memory and its role in collective intelligence by training homing pigeons to navigate home in pairs and testing their retention of learned routes. In a treatment with an eight-week forgetting period between training and memory testing, pairs flew closer to their learned routes than solo-tested birds, likely through differential retention of information across pairs. However, better memory retention in pairs did not translate into better homing efficiency, perhaps because the forgetting period was too short to generate a sufficient drop in efficiency. A second treatment demonstrated that extra training and a shorter forgetting period abolished the difference between paired and solo memory performance. These findings demonstrate that differential retention of information across group members can lead to the emergence of collective memory in animals. This has implications for a wide range of contexts in which the interplay of learning and memory shape individual and collective behaviour.

In both humans and non-human animals, collectives can sometimes overcome individual cognitive biases or shortcomings to execute more rational behaviour than individuals. To investigate differences in strategy and outcome between individuals and collectives in a logical reasoning task, we presented an inverted U-shaped tube to individuals and pairs of chimpanzees (Pan troglodytes) and examined their preparatory actions towards rewards that could fall from either end of the tube. Given that individual chimpanzees have typically produced a suboptimal one-handed strategy in past variants of this task, we predicted that pairs would outperform individuals primarily through subjects sharing the apparatus, each placing one hand under one tube end such that they collectively account for both possible outcomes. Unexpectedly, over half of our chimpanzees spontaneously produced the optimal two-handed behaviour (covering both ends) on their own, providing evidence that individuals may be able to reason about mutually exclusive future possibilities. This reduced the capacity for pairs to improve upon individual performance. Notably, however, we observed an increase in individual usage of the two-handed strategy in the collective setting. This individual improvement may have arisen from an effect of collective facilitation, such as competition, suggesting an alternative mechanism through which collectives may outperform individuals. This article is part of the theme issue 'The evolution of collective intelligence'.

Collective vigilance describes how animals in groups benefit from the predator detection efforts of others. Empirical observations typically find either a many-eyes strategy with all (or many) group members maintaining a low level of individual vigilance, or a sentinel strategy with one (or a few) individuals maintaining a high level of individual vigilance while others do not. With an analytical treatment that makes minimal assumptions, we show that these two strategies are alternative solutions to the same adaptive problem of balancing the costs of predation and vigilance. Which strategy is preferred depends on how costs scale with the level of individual vigilance: Many-eyes strategies are preferred where costs of vigilance rise gently at low levels but become steeper at higher levels (convex; e.g., an open field); sentinel strategies are preferred where costs of vigilance rise steeply at low levels and then flatten out (concave; e.g., environments with vantage points). This same dichotomy emerges whether individuals act selfishly to optimize their own fitness or cooperatively to optimize group fitness. The model is extended to explain discrete behavioral switching between strategies, differential levels of vigilance such as edge effects, and turn-taking.

"Terrestrial" primates are not common nor well defined across the order. In those species that do use the ground, terrestriality is rarely documented outside daylight hours. Predation risk is thought to have shaped conserved behaviors like primates' selection of arboreal sleep sites, but it is less clear-particularly at the landscape scale-how predation risk interacts with other ecological and seasonal variables to drive terrestriality. This camera trapping study investigates patterns in terrestrial behavior both spatially and temporally across neighboring populations of chacma baboons. We use camera trap data from two terrestrial grids, one established within and one outside the boundaries of Gorongosa National Park, Mozambique. We model how baboon terrestrial activity varies with woody cover, proximity to water, season, anthropogenic variables, as well as predation risk. We also model how terrestrial activity varies across the diel cycle and use overlap analyses to explore differences in the baboon populations' activity patterns. We find no significant predictors of geospatial variation in the terrestrial activity of baboons across each grid but do find evidence of higher terrestrial activity in the late dry season. We also find significantly different diel patterns of baboon activity detected across each grid. Baboons likely use the ground more in the dry season for accessing water and resources when arboreal foods are less abundant. Diel variation between the two populations suggests that baboons might utilize the ground more during "riskier" crepuscular and nocturnal hours where leopards are not present.

IntroductionRoute-based navigation is a common movement strategy for a variety of taxa, wherein animals repeatedly re-use familiar paths during travel. However, this type of navigation is understudied in wild animals that experience regular displacement, raising questions about the robustness and longevity of such routes and route memories. The seasonal flooding of Gorongosa National Park, Mozambique, provides an opportunity to test multiple facets of route-based navigation in wild primates, due to its high seasonality and annual flooding.MethodsData was collected from GPS collars placed on four chacma baboons in two troops in Gorongosa National Park. Using GPS points taken every 15 minutes, we use nearest-neighbour analysis to compare daily paths across the year, to identify high-use paths. We then look at the identified high-use paths to see if they are used across the entire study period, with a focus on areas that were vacated for more than two months of the study period.ResultsWe find that the baboons do have vacated areas, but return to the same areas after displacement. We did not find high-use routes in these areas used both before and after displacement, although high-use routes did exist that were used across the study period in different areas.DiscussionOur results indicate that routes may not be maintained in long-term memory spanning several months, or that route reuse is in part dependant on seasonal resources or navigational aids. Although the study period did not span a full year, this study presents a replicable method of analysing route reuse and identifying high-use routes without traditional methods of manually overlaying and analysing daily paths.

OBJECTIVES:This research aimed to understand how sleep site selection compared to other study sites in baboons living in a low-predator density, highly seasonal environment. We compared baboon troops in two distinct habitat types with different seasonal influences within the park, one that flooded annually and one that did not. We compared their sleep site use, reuse, and location relative to home range boundaries and areas of interest (AOIs) with each other and baboons in other areas to understand whether season, habitat familiarity, or position in the home range influenced sleep site choice. METHODS:Using GPS collar data taken at 15-min intervals from four gray-footed chacma baboons (Papio ursinus griseipes) in Gorongosa National Park, Mozambique, we established the location of sleep sites, home range boundaries, and AOIs, or places where the baboons repeatedly stopped for more than 15 min. Study subjects ranged either in dense woodland or in a seasonally flooded alluvial floodplain. We used a linear mixed-effects model to predict sleep site reuse based on distance to the habitat edge and AOIs, and Wilcoxon signed-rank tests to determine if morning or evening AOIs influenced sleep site location. We counted the number of reuses of each sleep site before and after the flooding period and compared this data to data in other baboon study sites. RESULTS:We found that, as in other study sites with less seasonality and higher predation risk, baboons in Gorongosa change sleep site frequently and utilize multiple sleep sites throughout their home range, although they more often use sleep sites closer to the center of their home ranges. However, unlike other studies, we found that the location of the last AOI of the day more strongly predicted sleep site location than the first AOI of the next day in one troop, with baboons traveling further from their sleep site to their first AOI in the morning than from their last evening AOI to the sleep site. CONCLUSIONS:Despite high seasonality and low predator density, baboons in Gorongosa National Park changed sleep sites frequently, as do other studied baboon troops in areas with high nocturnal predation rates. In addition, their propensity to sleep closer to the last AOI of the day may imply that they plan their daily paths toward their chosen sleep site, or that they sleep opportunistically at the end of the day. This study provides a baseline of behavioral data for comparison to other sites and future work in Gorongosa, where predator density continues to rise since the time of the study.

OBJECTIVES:Baboons possess sophisticated physical and social cognitive abilities; hence, the lack of evidence to date of large-scale behavioral variation in these primates is puzzling. Here we studied a candidate for such variation-the stripping of bark from Acacia robusta trees for consumption of the sap and soft tissue underneath-in Gorongosa National Park, Mozambique. MATERIALS AND METHODS:We surveyed an area inhabited by ~60 troops of chacma baboons, recording the availability and characteristics of the target trees, as well as the presence or absence of bark-stripping at 45 habitat plots distributed across a grid covering an area of ~300 km2. RESULTS:Camera traps confirmed the presence of baboons at all habitat plots, and we identified regional clumping in the distribution of the behavior, a pattern consistent across two consecutive years. Proportion and mean height/width of A. robusta did not predict whether bark-stripping behavior was present at a given site, nor did broader ecological variables such as habitat type and distance to the nearest water source. However, stripping sites had significantly higher numbers of A. robusta than non-stripping sites, and within a given bark-stripping site, baboons preferred to strip taller and wider trees among those available. DISCUSSION:The prominent geographical clustering we uncovered may have been driven by opportunity (i.e., the prevalence of A. robusta at a given site), but is also consistent with a possible (non-mutually exclusive) cultural interpretation. We propose avenues for future research on Gorongosa's baboons to better quantify the relative contributions of ecology, genetics, and social learning to the prevalence of bark stripping. We also briefly consider the potential relevance of baboon bark stripping to elucidating early hominin foraging strategies.

The ability to scan visual scenes to gather information is a critical adaptive skill across primates. The common marmoset, a small-bodied New World monkey and emerging model of social and visual neuroscience, relies heavily on rapid head movements in addition to eye movements to orient (Pandey et al., 2020; Singh et al., 2025). Previous studies have found a relatively restricted oculomotor range extending out about 10 visual degrees from the central position of rest (Mitchell et al., 2014; Singh et al., 2025). However, previous studies have either used empty arenas for exploration (Singh et al., 2025), or in head-fixed animals used exploration of images potentially biased centrally with posed stimuli (Mitchell et al., 2014). This leaves open questions about whether this restricted oculomotor range is due to physical constraints or a lack of attention-drawing stimuli in the periphery. Understanding marmosets' oculomotor range is important for applying modern methods that use marker-less pose tracking of the head as a proxy for gaze direction, under the assumption eye gaze is relatively restricted and can be ignored (Meisner et al., 2025). Using high-precision eye tracking and free-viewing of a natural image and video with objects of interest placed in the periphery, we quantified the oculomotor range of head-fixed marmosets. Our results show limited changes in the range reported from previous studies, even with naturalistic stimuli including moving animals that were optimized to encourage peripheral viewing.

Animals vary consistently in traits such as boldness and stress reactivity, which influence fitness, movement, and social dynamics. Identifying genetic variants linked to these behaviours can clarify proximate mechanisms and evolutionary trade-offs. Dopaminergic (DRD4) and serotonergic (TPH2) pathways are known to modulate exploration and emotionality, while LDHA contributes to neuroenergetics and endurance, yet their combined role in shaping behavioural diversity remains unclear. Here we show, in 137 homing pigeons, that a SNP at position C382T in DRD4 and T185A in TPH2 are significantly associated with boldness. Birds with DRD4 T/T and TPH2 T/A genotypes emerged more quickly from the shelter. We also found that DRD4 C/C and TPH2 T/A genotypes were associated with slower recovery from acute social isolation stress, quantified by eye infrared thermography. In addition, a microsatellite polymorphism in LDHA intron 6 interacted with the presence of a mirror companion, suggesting a genotype-dependent effect of social buffering. These findings provide evidence that common genetic variants in neuromodulatory and metabolic genes contribute jointly to behavioural and physiological syndromes in birds, and social context can interact with genotype to influence stress resilience. We demonstrate how candidate markers are useful in exploring the ecological and evolutionary consequences of personality variation.

We know vanishingly little about how long-lived apes experience senescence in the wild, particularly with respect to their foraging behaviors. Chimpanzees use tools during foraging, and given the cognitive and physical challenges presented by tool use, tool-use behaviors are potentially at a heightened risk of senescence, though this has never been investigated in wild individuals. Accordingly, we sampled data from a longitudinal video archive that contained footage of wild chimpanzees using stone hammers and anvils to crack hard-shelled nuts (nut cracking) at an ‘outdoor laboratory’ over a 17-year period (with focal chimpanzees aging from approximately 39–44 to 56–61 years across this period). Over time, elderly chimpanzees began attending experimental nut-cracking sites less frequently than younger individuals. Several elderly chimpanzees exhibited reductions in efficiency across multiple stages of nut cracking, including taking longer to both select stone tools prior to use and use tools to crack open nuts and consume the associated pieces of kernel. Two chimpanzees began using less streamlined behavioral sequences to crack nuts, including a greater number of actions (such as more numerous hammer strikes). Notably, we report interindividual variability in the extent to which elderly chimpanzees’ tool-use behaviors changed during our sample period – ranging from small to profound reductions in engagement and efficiency – as well as differences in the specific aspects of nut cracking that changed for each individual. We discuss the possible causes of these changes – and recommendations for future research – with reference to literature surrounding the senescence of captive and wild primates.

Dispersal behavior influences gene flow and the spatial distribution of genetic diversity, which is crucial for a species' evolutionary trajectory and population persistence under environmental changes. We used gene flow as a proxy to investigate dispersal patterns in the grayfoot chacma baboon (Papio ursinus griseipes) in Gorongosa National Park (GNP), central Mozambique. The baboons inhabit a mosaic landscape with a seasonally variable environment. Thirty-two years ago, GNP was the epicenter of a major war that severely reduced apex predators, resulting in limited mammalian predation on baboons. We aimed to characterize genetic diversity, examine the extent and direction of sex-biased gene flow at different time frames and investigate changes in population size and recent migration events. We collected 121 non-invasive DNA samples and analyzed uni- and bi-parentally inherited markers, comprising mitochondrial DNA, autosomal and Y-linked microsatellites, at two geographic locations (GNP and Catapú Forest Reserve) 150 km apart. We observed high genetic diversity and no evidence of a recent population decline. We identified six mitochondrial haplotypes, including a genetically distinct one in Catapu Forest Reserve. We found molecular evidence for historical and current male-mediated gene flow and female philopatry. Our results highlight the resilience of dispersal patterns in Papio sp. in diverse and seasonally variable ecosystems which have been disturbed by anthropogenic activities.

The ability to navigate through both familiar and unfamiliar environments is of critical importance for foraging efficiency, safety, and energy budgeting in wild animals. For animals that remain in the same home range annually, such as grey-footed chacma baboons (Papio ursinus griseipes), movement efficiency is expected to reflect familiarity with the home range as well as the nature of the resources within it. For example, resources that are patchy, transient, or seasonal present a greater spatial cognitive challenge, and travel between them may be less efficient than for more widespread or permanent resources. Here, we analyse daily route efficiency in adult female grey-footed chacma baboons at Gorongosa National Park, Mozambique. We use GPS data taken at 15 min intervals from collars deployed on two baboons in each of two study troops (four total) to identify areas of interest used during daily ranging periods (sleep site to sleep site). We then compare the length of the route taken between a given day’s patches to routes calculated by two alternate optimisation heuristics as follows: the nearest neighbour method, in which the subject repeatedly travels to the next most proximate patch and does not necessarily return to the same place, and the Concorde algorithm, which calculates the shortest possible route connecting the day’s patches. We show that baboons travel more efficient routes than those yielded by the nearest-neighbour heuristic but less efficient routes than the Concorde method, implying some degree of route planning. We discuss our novel method of area of interest identification using only remote GPS data, as well as the implications of our findings for primate movement and cognition.

Why do collectives outperform individuals when solving some problems? Fundamentally, collectives have greater computational resources with more sensory information, more memory, more processing capacity, and more ways to act. While greater resources present opportunities, there are also challenges in coordination and cooperation inherent in collectives with distributed, modular structures. Despite these challenges, we show how collective resource advantages lead directly to well-known forms of collective intelligence including the wisdom of the crowd, collective sensing, division of labour, and cultural learning. Our framework also generates testable predictions about collective capabilities in distributed reasoning and context-dependent behavioural switching. Through case studies of animal navigation and decision-making, we demonstrate how collectives leverage their computational resources to solve problems not only more effectively than individuals, but by using qualitatively different problem-solving strategies.