Animal Behaviour

Communication allows organisms to quickly convey information vital for survival or fitness. Chemical communication and speed-accuracy trade-offs are ubiquitous in animal decision making. Most studies have used species which forage mainly above-ground species, tested in an epigean setting, but it remains unclear whether below-ground species behave similarly. Here, we use the below-ground ant Tetramorium alpestre to assess the efficacy of above- vs. below-ground mazes, the accuracy of decisions when using natural vs. artificial pheromones, the presence of a speed-accuracy trade-off, and the pheromones effect on aggression. Ants decided more quickly under below-ground than above-ground conditions, indicating they may be distracted by above-ground stimuli. Ants followed both natural and artificial trails but in direct competition preferred artificial trails, likely due to a higher pheromone concentration. Surprisingly, no speed-accuracy trade off was observed during path decision-making. Lastly, population origin but not pheromones affected if and how aggression occurred in presence of trail and home-range marking pheromones. We argue that the design of behavioural tests should match the lifestyle of the focal organism. We further speculate that speed-accuracy trade-offs likely are highly species- and context-specific and other factors besides chemicals seem important to trigger aggression, at least in this species.

BackgroundVolubility, the number of vocalizations per unit of time, is a relatively understudied aspect of animal communication, potentially crucial in highly social systems like cooperative breeders that depend on coordinated behavior. Callitrichid monkeys, including common marmosets (Callithrix jacchus), are often characterized as highly vocal, yet the variation in their calling rates due to context or individual differences remains poorly quantified. In this study, we systematically examined captive marmoset volubility across different social and informational contexts, call types, and individual characteristics. ResultsWe tested marmosets in dyads in different experimental conditions and recorded a total of 70,260 vocalizations. Overall, calling rates were not influenced by sex or status. Instead, volubility varied mainly with condition: rates increased when visually separated from the partner and individually encountering ecologically salient stimuli such as ambiguous objects or food, consistent with context-sensitive signaling and information asymmetry. Contact calls were more frequent in food-related contexts, indicating a recruiting function. Arousal calls were strongly predicted by age, with younger individuals calling more, especially when confronted with an ambiguous object. Food calls occurred almost exclusively during direct interactions with food, particularly during feeding. Dyadic analyses revealed covariation between callers and partners arousal calls, consistent with vocal contagion. In contrast, we found no contagion effects for food calls. Instead, food calls by a breeder encountering food increased contact calling in their naive dyad partners. ConclusionsOverall, marmoset volubility is flexible and call-type-specific, shows signatures of information sharing under information asymmetry, and highlights their nuanced communication strategies.

The ability of animals to innovate - solve novel problems - can shape their ecology and evolution. Here we investigate how individual traits and environmental complexity relate to successful solving of a novel problem. We presented foraging bumble bees (Bombus impatiens) with artificial flowers of not-previously-encountered shapes and recorded the bees latency to access nectar. We measured individual foraging traits across multiple trips with simple flowers that did not require innovation, and bees were foraging either in a simple or complex environment (cluttered flight arena). Bees in complex environments took longer to find and were less likely to land on novel flowers, indicating that environmental complexity may take up cognitive resources and make search more difficult. However, we did not find an effect of environmental treatment on the ability or time to access reward in novel flowers once bees had landed on them. In contrast, behavioral traits significantly predicted how quickly bees solved novel flowers. In particular, overall foraging tempo as well as routine formation, i.e. how much bees followed a fixed route on known flowers, predicted innovation - faster bees innovated faster, and bees with more repetitive foraging sequences were slower to solve the novel tasks. Overall, while the degree of evolutionary novelty in tasks or solutions is always hard to evaluate, our findings demonstrate that environment and individual traits may affect innovation in different ways. Individuals in simple environments may be more likely to detect, and individuals that are generally faster and have a lower tendency to develop fixed routines may be more likely to solve, novel tasks.

Predation is a driving force in the ecology and evolution of prey, and primates exhibit diverse anti-predator strategies for minimizing risk. Because these behaviors can be costly, individuals must balance costs and benefits when responding to perceived threats. The cognitive capacity and behavioral plasticity of baboons make them an ideal taxon for studying the context-dependent variation in anti-predator strategies. Here, we used an autonomous, motion-activated playback experiment to study the behavioral responses of chacma baboons (Papio ursinus griseipes) to simulated predator encounters in Gorongosa National Park, Mozambique. We compared responses in 2021, when predator densities were relatively low, to responses in 2024, after predation increased due to lion (Panthera leo) population recovery and African wild dog (Lycaon pictus) reintroduction. We compared flight and vigilance responses to vocalizations of these common predators with responses to leopard (Panthera pardus), historically a key predator; spotted hyena (Crocuta crocuta), a rare predator; and cheetah (Acinonyx jubatus), absent historically and currently. We also assessed how responses varied with habitat, age-sex class, presence of offspring, and group size. Across 916 predator playbacks, baboons fled in 19% and displayed vigilance in 71% of trials. When predator density was higher, baboons displayed weakened antipredator responses, consistent with the risk allocation hypothesis. Baboons were more likely to flee in response to lion and wild dog cues. Juveniles fled more frequently than other demographic classes, while adult females with offspring were more vigilant. Overall, responses were highly heterogeneous, reflecting the substantial intraspecific variation and behavioral flexibility characteristic of baboons.

Traditionally, primates have been considered primarily visual animals. However, studies across a variety of taxa suggest that, in the context of food evaluation, the reliance on this sense might be more nuanced that previously thought, with dietary specialization and food item properties leading to differences in sensory prioritization. We performed a field-based study assessing the use of sensory cues during food evaluation as well as food-related behaviours such as muzzle contact in two mixed-sex groups of wild vervet monkeys including three age classes over a period of five months (nmonkeys = 44). Using a total of 18868 food evaluation observations collected over 44 hours of focal follows, we found that vervets mainly relied on their sense of vision when evaluating food (96.8% of all instances). Sensory usage varied according to food category and sex differences were only observed in the use of smell for a subset of these. Juveniles initiated muzzle contact and used tactile inspection more often than adults whereas females received muzzle contact more often than males. In addition, the low rejection rates suggest that most food items were familiar to the vervets regardless of age and sex. These findings are in line with optimal foraging theory according to which the food evaluation process should be adapted to the familiarity of food items and allows individuals to maximize their intake of energy and critical nutrients, while minimizing the time and effort in food evaluation.

Urbanisation is one of the most important forms of human-driven landscape change, altering wildlife populations in unprecedented ways. In terms of behaviour, for example, urbanisation is hypothesised to increase the likelihood of observing urban populations touching, exploring, and solving novel food-related tasks compared to rural areas. However, little is known about the impact of spatiotemporal patterns of urbanisation, particularly historical patterns of change, on these behaviours. We tested this in the worlds most urbanised carnivore, the red fox (Vulpes vulpes), by introducing novel food-related tasks (puzzle feeders) to 284 sites throughout Great Britain. We compared tactile and problem-solving behaviours in rural populations, recently colonised urban populations, and long-established urban populations (>40 years). Foxes from 27.4% of locations touched the tasks, foxes from 12.4% of locations solved them. Urban foxes were more likely to touch tasks compared to rural populations. Exploration time, exploratory diversity, and latency to touch tasks did not significantly differ across urban and rural locations. Urbanisation rate from 1994 to 2020 (26 years) did not significantly predict the likelihood of foxes touching or solving tasks across locations. Older urban populations - particularly from London - spent more time exploring tasks and displayed greater exploratory diversity and higher problem-solving success, despite more recent urban populations being equally likely to touch them. Collectively, our findings suggest that certain population characteristics, such as the likelihood of touching/engaging with novelty, potentially emerge early in urbanisation while other characteristics, such as greater exploratory and innovative behaviours, may emerge after long-term urban exposure across many decades. HighlightsO_LIHistorical impacts of urbanisation on wild animal behaviour are unclear. C_LIO_LIWe tested this with wild red foxes responses to novel food objects. C_LIO_LIUrban foxes were more likely to touch and exploit objects, especially from London. C_LIO_LIOlder urban foxes displayed more exploratory and innovative behaviours. C_LIO_LILength of urban exposure may help predict behavioural responses to novelty. C_LI

Parental care can shape post-fledging behaviour through provisioning, guidance and social information, yet its absence may alter how young birds establish space use and habitat preferences. We tested the consequences of absent parental care by comparing, hand-reared juvenile herring gulls released without parents with wild, parent-reared conspecifics, focusing on the first two months after fledging. Wild juveniles frequently revisited their natal nest during the first month, whereas hand-reared birds rarely returned to the release site; revisits declined in both groups by the second month but remained more common in wild birds. Wild juveniles used smaller ranges that subsequently expanded, while hand-reared birds began with larger ranges that later contracted, leading to convergence. Contrary to expectation, wild juveniles occurred in areas with higher human population density than hand-reared birds. Habitat use also differed between groups and changed over time. Early on, wild juveniles concentrated activity in anthropogenic and marine habitats, whereas hand-reared birds used rural green habitats more. Later, both groups shifted away from marine areas towards rural green habitats, reducing but not eliminating between-group differences. Short-term survival, did not differ between hand-reared and wild juveniles, indicating that parental care primarily reshaped early space use and habitat choice rather than immediate survival.

Finding resources for the colony is one of the most difficult and risky tasks for a social insect worker. A worker on a foraging trip can face a number of challenges, including interference from other individuals, her own errors, and environmental disturbances. Collectively, colonies may use a variety of strategies to minimize the impact of such perturbations on the foraging process. Here, we investigated how individual Solenopsis xyloni ant workers react to perturbation of an established pheromone trail. We trained foragers from colonies in the field to either a low or high concentration sucrose solution in a feeder on a T-maze setup, then replaced a section of floor covering, removing a section of the pheromone trail previously laid. We found that while ants made correct choices on the T-maze when the trail was intact, their choices did not differ from chance when the trail was absent, indicating strong reliance on a pheromone trail (and not, for example, memory) to return to the resource. Moreover, when the trail was absent, we found that a majority of ants abandoned the resource, and that even the ants that were able to reach the resource did not repair the perturbed trail. However, with a high-quality resource, more ants persisted in attempting to reach it (instead of abandoning). We interpret these responses in the framework of robustness mechanisms discussed in systems biology. Our study thus links individual and collective responses to perturbations, and provides an empirical example of how information use interacts with system robustness. Statements and declarationsThe authors have no competing interests to declare that are relevant to the content of this article.

Foraging bee decision-making research has focused on choice determinants, and the variability and underlying causes of pre-choice latency remain understudied. Here, individual bumblebees (Bombus impatiens) were trained to associate one colored stimulus with a medium-value reward and another with a novel, higher-value reward. The experimental design consists of seven blocks, each containing four consecutive single-stimulus presentations followed by a forced binary choice. The latency to choose a stimulus and the type of choice during dual-choice trials were analysed. In dual-choice trials, bees in the yellow-high reward group showed a slower increase in high-reward selection than those in the blue-high group, suggesting persistent innate color bias. Response latencies for the low-reward stimulus systematically increased across blocks, indicating progressive devaluation. Early learning phases showed a temporary increase in response latency, extending previous findings on experience-dependent adjustments in acceptance thresholds. Latency in single-stimulus trials correlated with binary choice results, though choice proved a stronger indicator of preference than latency. Certain options elicited faster responses when presented with an alternative than when presented alone. Together, these findings support a deliberative model of bumblebee decision-making, in which pre-choice latency is modulated by innate preferences, associative learning, and immediate context.

From facial expressions to gestures, animals use multiple signal modalities to express emotions and communicate. In dogs, tail movements are conspicuous behaviours associated with emotional states, but this link remains debated. We investigated canine emotional states underlying tail wagging by systematically analysing differences in tail movements in a computer-controlled task encompassing two non-social Conditions - Rewarded (positive) and Unrewarded (negative), and two Epochs (pre-response and outcome anticipation). Using pose-tracking we found that 11 out of 23 dogs did not wag their tails in at least 75% of trials, suggesting that some dogs may inherently wag less or that tail wagging is primarily a social signal. Our results showed that dogs were more likely to wag during positive anticipation; whereas in the negative condition, despite tail amplitude being more prominent, increased speeds reflected arousal rather than valence. Further work should assess tail kinematics in social contexts to test and extend these findings.

Corvids - members of the crow family - exhibit some of the most sophisticated cognitive abilities outside the primate lineage, yet the developmental origins of many of these abilities remain poorly understood. Here, we present a systematic review of the past 20 years (from 2005) of empirical research on corvid cognitive development, synthesising evidence across core/ foundational, social and physical cognitive domains. Using a structured search strategy and detailed coding framework, we identified 47 relevant studies spanning 16 corvid species. We evaluate and discuss developmental trajectories, species/ taxa-level variation and methodological robustness across studies. For within and between-taxa comparisons, we particularly focus on the best represented abilities in the coded sample: 1) object permanence and caching; 2) tool-use/ manufacture; 3) object manipulation and play; and 4) gaze following. Corvid developmental patterns show both parallels and divergences from those documented in primates and other taxa. However, the existing corvid evidence base is constrained by small samples, captive biases, limited longitudinal data and under-representation of key cognitive abilities, such as executive function, causal reasoning, self-control, metacognition, spatial memory and social learning. We outline critical gaps and future directions, emphasising the need for comparative, longitudinal and ecologically grounded approaches, including the science of magic and Theory of Mind, to better understand how early-life cognition shapes later behaviour, cognition and fitness in this model avian family.

Sentinel behaviour occurs when individuals use raised positions to scan for predators while the rest of the group forages. Here, we investigated whether a colonial cooperatively breeding species that forages in large groups, the sociable weaver, Philetairus socius, displays sentinel behaviour. This behaviour has been reported in species with similar ecology, behaviour and foraging habits, (e.g. ground foraging in open habitats where aerial predators are common) and, hence, we expected that it could occur in sociable weavers. On the other hand, sentinel behaviour appears to be less common in species that live in very large groups. We used an experimental set-up consisting of an artificial feeding station and perches to assess occurrence of sentinel related behaviours: (i) perching events > 30s on an elevated position, (ii) head-movements and (iii) alarm calling. Birds were seldom observed perching while others fed, and those that did, perched for periods that were too short to be considered as sentinel behaviour (less than 5s on average). Our results suggest that this behaviour is uncommon or even absent in sociable weavers. We discuss whether other factors such as foraging in very large groups, or interspecific foraging associations might make sentinel behaviour less important in this species.

Object play - seemingly non-functional interactions with objects - can promote the development of foraging skills, tool use, and behavioral innovation. Among Catarrhine monkeys, it was described in macaques and baboons. Wild geladas, although closely related to baboons, have been described as lacking object play (observed only in captivity) linked to their specialized grazing ecology. Here, we provide the first evidence of both social and solitary object play in a wild gelada population (NOMUs=13) at Debre Libanos (Ethiopia) and compare it with object play in sympatric olive baboons (Nindividuals=42). Notably, immature geladas engaged in object play both socially and solitarily, but the latter case was most frequent also with novel objects introduced by researchers. Solitary object play occurred at levels comparable to those of baboons, challenging previous reports of limited object interest in geladas. This finding aligns with the occurrence of object play in phylogenetically related species and with the retention in wild geladas of arboreal behavior and fruit consumption and hand morphology enhancing fine manipulation. Hence, object play in geladas under certain environmental conditions may reflect a biologically rooted capacity and underscores the importance of ecological variability, as distinct behavioral ecotypes can emerge across different populations of the same species.

When novel nutrient-rich food sources become available to species sharing the same natural habitat, interspecies competition may arise, yielding insights into the ecological and social dynamics of the observed species. Here, we investigated food consumption patterns, and consequent social interactions, by two sympatric species of mice in response to a novel nutrient-rich food source. By deploying, in the mices natural habitat, baited video-monitored chambers, we collected, over a 5-month period, 1805 observations of food visiting by Apodemus agrarius and Apodemus flavicollis. We also documented interspecific encounters, with 86.7% of the cases showing agonism. In these interspecies agonistic encounters, A. flavicollis was always the initiator of agonism, attacking within 2 sec in 92.3% of the cases, and being dominant over A. agrarius in 84.6%. Analysis of food visiting behavior revealed that, initially, both species preferred nocturnality. However, after the interspecies fights, A. agrarius switched its temporal preference to diurnality, leading to temporal niche segregation between the two species and a significant reduction of interspecies encounters. Moreover, A. agrarius demonstrated hour-specific avoidance of A. flavicollis, visiting significantly less in hours with A. flavicollis compared to hours without. Through temporal niche switching, A. agrarius managed to access the food source safely, without fights. In contrast, A. flavicollis remained consistently nocturnal across the entire study. Notably, our study presents the first 24h foraging actogram for free-living rodents. Moreover, while rodent interspecific competition is a well-known phenomenon, most of what we know about it comes from indirect observations. Direct observations of rodent interspecific interactions in nature are rare. Our work is the first direct (video-monitored) observation of temporal switch-inducing interspecies interactions in nature. As free-living rodents are currently considered a major model system for the study of interspecific competition, these results may offer precious insights for a better understanding of social dynamics, especially in asymmetric relationships. Furthermore, our findings highlight the significance of considering temporal dynamics in studies of interspecific interactions.

Group living often improves decision accuracy in animals, yet whether increasing group size buffers against context-dependent biases remains unexplored. One such bias is the decoy effect, where the presence of a third option shifts preferences between two alternatives. Here, we tested whether introducing a decoy shoal influences collective preference for the larger female shoal in adult male zebrafish (Danio rerio), and whether the strength of this effect depends on group size. Groups of two, three, or four males were presented with female shoals under two choice contexts: a dichotomous contrast (four vs. two fish) and a trichotomous contrast including an additional alternative of one, three, or five fish. The order of presentation (dichotomous-first or trichotomous-first) was counterbalanced, and multi-animal tracking was used to quantify group-level shoal-size preference (time spent near shoals), inter-individual distance (IID), polarization, and swimming speed. In the dichotomous-first order, across all group sizes, subject shoals consistently showed a baseline preference for the larger shoal. Adding a third decoy option altered this preference only when the decoy was extreme (one or five fish relative to the 4 vs. 2 alternatives), reducing relative preference toward indifference. Group IIDs were associated with context-dependent shifts in relative preference in the dichotomous-first order, whereas polarization and swimming speed were not. In the trichotomous-first order, groups showed no preference for the larger shoal, with or without a decoy shoal. Our results demonstrate that context-dependent biases, shape collective shoal choice, with effects driven by choice structure and order of presentation of options than by group size.

1.Many group-living mammals and birds groom the fur (or preen the feathers) of their close associates, and this social grooming (or social preening) seems to build and maintain affiliative relationships. Female common vampire bats (Desmodus rotundus) lick each other in ways that appear to be responsive to cues of need, which suggests that this social grooming could be a low-cost form of helping in addition to being a social signal. If social grooming is a form of helping, then vampire bats should preferentially groom others in locations that are difficult to self-groom. We show that social grooming (n = 1586 events) did indeed occur most often on parts of the recipients body where self-grooming (n = 1515 events) was least likely, often in locations where the recipient could not lick itself, like the back of the head. The finding that vampire bats preferentially groom each other in hard-to-reach locations provides further support for the hypothesis that social grooming is a low-cost form of help in vampire bats.

Group-living animals often coordinate their behavior using "contact calls". Identifying the function of these calls requires testing whether they are intended for any group member or targeted to specific preferred associates. If contact calling is used to coordinate with preferred associates, then higher rates of contact calling are expected between group members with a history of more frequent affiliation and cooperation. To test this hypothesis, we constructed a contact-calling network using synchronized recordings of vocal interactions between all 28 possible pairs of 8 female common vampire bats with well-sampled histories of social grooming and regurgitated food sharing. Bayesian multilevel models show that pairwise rates of contact calling were clearly predicted by social grooming and cooperative allofeeding rates in ways not explained by kinship. These findings show that common vampire bats use contact calls to coordinate with specific same-sex associates, unlike other studied bat species where individuals produce contact calls at similar rates towards different group members. We also found that, compared to white-winged vampire bats, common vampire bats are ten times less likely to rapidly respond to a contact call; this suggests yet-to-be-discovered differences in social behavior between vampire bat species. Finally, we discuss implications for the vocal grooming hypothesis.

Social living is widely considered a key driver of cognitive evolution, yet individuals within a species and even within the same group can differ substantially in their sociability (i.e., an individuals propensity to form and maintain social bonds), which can ultimately shape the social environment they experience by influencing how they interact with, respond to, and engage in it. How such individual variation in this personality trait affects social cognition, however, remains poorly understood. To address this question, we used two selectively bred lines of Japanese quail (Coturnix japonica) that consistently differ in social motivation, a key component of sociability, which we used as a proxy for this broader trait. In these lines, S+ individuals show high social motivation, whereas S- individuals show low social motivation. We compared their sociocognitive performance across three tasks: a gaze following task, a social buffering task, and a social discrimination learning task. Our findings revealed that Japanese quail reliably followed the gaze of conspecifics, providing the first evidence of this ability in this species. However, there was no difference between lines, suggesting that basic gaze following into the distance is independent of social motivation. In contrast, line differences emerged in the other tasks. S+ quail were more sensitive and less adaptable in response to environmental changes, particularly under social isolation, although the presence of a conspecific strongly buffered these effects. S- quail, on the other hand, outperformed S+ individuals in the social discrimination learning task, rapidly exploiting available social cues to guide foraging decisions. Overall, this study demonstrates that social motivation modulates sociocognitive performance in a context-dependent manner. Rather than conferring a general cognitive advantage, divergent selection on social motivation leads to different strategies of social information use across tasks and contexts, highlighting the complex interplay between personality, social environment, and cognition.

Reports of honeybees demonstrating abstract concepts like sameness and difference marked a pivotal development in comparative psychology. Subsequent studies expanded the scope of concept learning in honeybee cognition, yet most evidence relies on a single method: the delayed-matching-to-sample task using a Y-maze. Whether this setup is uniquely effective or if alternative approaches could yield similar results remains unresolved. Additionally, the failure of bumblebees (Bombus spp.) to complete this task, despite honeybees demonstrating success, remains unexplained. This study compared the performance of honeybees (Apis mellifera) and bumblebees (Bombus terrestris) across matching-to-sample tasks with varying degrees of physical continuity between sample and target stimuli. The objectives were twofold: to evaluate an alternative method for assessing concept learning in both species and to investigate potential species differences in such tasks. Contrary to prior findings, neither species succeeded at the reported proficiency levels in simultaneous matching-to-sample tasks. Moreover, bumblebees outperformed honeybees in one task. These results are consistent with an explanation based on species-specific differences in visual attention mechanisms, and underscore the need for further research on concept learning in social bees.

Protogynous sex change, where individuals first function as females and later as males, is a key life-history strategy among polygynous reef fishes. In haremic systems, sex change is typically socially regulated, with dominants suppressing subordinates sex change through aggression. Females within a harem form a size-based hierarchy that can remain stable in most species through the threat of eviction. We studied a different situation in the cleaner wrasse Labroides dimidiatus, where larger females have incomplete control, as they spend most of their time alone at their own cleaning territory. We tracked over 400 individuals for 12 months, recording growth, behavior, social organization, and sex change. We confirmed earlier reports that both sexes direct aggression primarily at those ranked immediately below them. However, we observed 30 cases where smaller females outgrew larger ones, revealing hierarchy instability. Of 42 sex change events, 43% occurred in presence of the male, and half of these early sex changers were not the largest female, but individuals overlooked by the male. Fast growth relative to harem-mates and harem switching increased the likelihood of sex change. Local population densities also influenced growth and sex change, with individuals in high-density demes growing faster and changing sex at larger sizes. Our findings reveal flexible sex change dynamics in a system with incomplete social dominance. Such incomplete control and observations that becoming male confers both higher reproductive success and survival highlight the need to expand game-theoretical and life-history frameworks to encompass such strategic flexibility. Lay summaryDominant cleaner wrasse cannot fully control subordinates as individuals occupy distinct core areas. Tracking 400 fish for a year, we found that smaller females could outgrow initially larger ones, and early sex change despite a larger male. Fast growth and harem switching increased the chances of becoming male. Population density also shaped these strategies. Our findings reveal flexible sex change dynamics in a system where becoming male confers both higher reproductive success and survival.