Animal Cognition最新文献

The biological market task – also known as the ephemeral reward task – models the mutualistic cleaning interactions between bluestreak cleaner wrasses and their client fish on coral reefs. In this dichotomous choice paradigm, selecting an “ephemeral” food option first grants access to a “permanent” food option, while choosing the permanent option first makes the ephemeral one unavailable. Cleaner fish have previously outperformed other vertebrates on this task, presumably because the cues to solve it are more ecologically salient for cleaner fish. In this study, we tested whether this advantage extends to non-cleaner fish by assessing the learning and reversal learning performance of three dottyback species (Pseudochromis spp.) – mesopredator reef fish that do not engage in cleaning mutualisms – on the original task and two derived versions that varied in the cue required for solving it. Dottybacks performed poorly in all versions of the task. Notably, they did worse in the original task than cleaner wrasses tested previously, suggesting that cleaner fish’ success is tied to specific ecological conditions not shared by other species. Further analyses revealed subtle differences in performance between tasks and faster learning in the initial test compared to the reversal test, an indicator of limited cognitive flexibility. Together, these findings help fill a gap in the biological market literature and underscore how species-specific ecological traits and task structure shape cognitive performance.

Grooming procedures are often stressful for dogs due to exposure to loud noises, unfamiliar individuals, and the absence of their owners. This study aimed to assess whether classical music could reduce stress-related behaviours in dogs during grooming. Fifteen companion dogs of various breeds, aged 2 to 8 years, were observed during three grooming sessions: a control session without music, and two experimental sessions featuring classical piano compositions–Beethoven’s Moonlight Sonata and Chopin’s Nocturne. Music was played at 75 dB to mask ambient salon noise. Stress-related behaviours were rated on a 5-point scale during bathing, drying, clipping, and nail trimming. Results showed that all dogs, but especially males, exhibited significantly calmer behaviour in the music conditions. Female dogs showed similar trends, though differences were not statistically significant between stages. These findings suggest that classical music is a simple, effective, non-invasive enrichment method that can enhance dog welfare in grooming environments.

Animals use vocal signals to provide information across a wide range of contexts. However, it is more complex to identify the information content when the same vocalizations are produced in different contexts, such as against predators and conspecific competitors. This raises the question whether information about the caller or context can be coded in relatively subtle variation within the call type and whether receivers respond differentially to such variation. Using playbacks of the general ‘chatter’ alarm call of Eurasian magpies (Pica pica), we tested whether or not territorial magpies respond differently to variation in call duration and rate. We show that magpies responded acoustically faster to chatters of longer duration, which may signal a greater motivation or urgency of territorial intruders. Alternatively, a delay in chatter response to shorter calls may reflect a period of hesitation and risk avoidance. Interestingly, magpies did not approach the loudspeaker more closely in response to longer calls and the total chatter response did not differ either. This suggests that after the short initial response, the persistence of the signal over time as well as visual information on the level or type of danger become essential for more differentiated response behaviours. Taken together, our results show that magpies perceive and respond differentially to variation in alarm call duration, suggesting that such variation encodes meaningful information.

An important element in understanding the evolution of human sociality is to understand the factors that governed the evolution of social organisation in our closest living relatives. The ‘social brain hypothesis’ proposes that the complex social world of primates is especially cognitively demanding, and that this imposed intense selection pressure for increasingly large brains. Group size in primates is strongly correlated with brain size but exactly what makes larger groups more ‘socially complex’ than smaller groups is still poorly understood. Chimpanzees and Gorillas are among our closest living relatives and they exhibit remarkable diversity in various aspects of their social organisation both within and across species. They are thus excellent species in which to investigate patterns of sociality and social complexity in primates, and to inform models of human social evolution. We propose a program of research that will provide the first systematic insight into how social structure differs in small, medium and large groups of Chimpanzees and Gorillas, to explore what makes larger groups more socially complex than smaller groups. Further, we propose to investigate how these variations in social structure in different size groups are affected by the social organisation of the species. Chimpanzees live in a fluid fission-fusion social system, whereas Gorillas have more stable, cohesive groups. To carry out both the within and between species comparisons, we advocate use of social network analysis, which provides a novel way to describe and compare social structure. This program of research will therefore lead to a new, systematic way of comparing social complexity across species, something that is lacking in current comparative studies of social structure. Considering that hominins were likely characterized by a fission-fusion social structure, comparing the social complexity of such systems with that of more stable groups may yield valuable insights into the evolution of human sociality.

Evidence increasingly reveals that non-human animals in monotonous situations can show boredom-like states, distinctively manifesting as increases in both arousal-seeking, restless behaviour and low arousal, drowsy behaviour. However, task related boredom has been little investigated in animals, but could have implications for animal training efficacy, for animal welfare, and for modelling human task fatigue. We investigated whether varied sensory stimuli helped prevent boredom-like behaviour in a repetitive foraging scenario, compared with a monotonous equivalent. In a cross-over design, 20 rats searched pairs of containers for a small reward hidden within a digging material, with a new pair of containers presented every 2 min during a 20 min session. Multisensory cues distinguished the rewarded vs. non-rewarded containers. We hypothesized that, if rats became bored by sensory monotony, rats in a monotonous version of the scenario would show more arousal-seeking (e.g. exit-directed behaviour, jumping) and drowsy behaviour (e.g. standing still, yawning, task disengagement) than in a varied version. In the Monotony treatment, the digging material, reward flavour, and features of the cues remained constant in each presentation, whereas these changed throughout the Variety treatment. Behaviour was observed blind to treatment in a randomised order. Monotony significantly increased exit-directed behaviour compared with Variety, but no other treatment effects reached significance. Possible reasons for the relative lack of findings are discussed, including suggestions for future research. Here, sensory monotony during the task did not induce the full range of behaviours characterizing boredom, but it is of interest that it did increase exit-directed behaviour.

Dogs and wolves communicate effectively with humans, yet differences in their human-directed facial expressions and the role of relationship strength in shaping these behaviours remain poorly understood. This study explored the facial expressions of human-socialized wolves and dogs when greeting a bonded or familiar human through a fence. We hypothesised that differences would arise due to the domestication process, shaped further by the strength of their relationship. Additionally considering the bidirectionality integral to greeting interactions, we explored whether humans show different facial displays toward dogs versus wolves, expecting stronger differences in less bonded human partners due to unconscious biases. There was little overall difference between wolves’ and dogs’ facial expressions. However, wolves mainly displayed attentive, forward-directed ears, whereas dogs exhibited more ear positions associated with ambivalence or submission, such as rotated and downward-pushed ears. Dogs spent more time in proximity, gazing and tail wagging towards the human than wolves while both species showed more displacement behaviours (paw lift, whining, yawn) with bonded than familiar human partners. Interestingly, humans displayed more frequent, intense, and positive facial expressions toward dogs than wolves, suggesting implicit biases in human attitudes that were only partially influenced by familiarity. These results highlight the complexity of (studying) human-animal interactions. To what extent dogs’ submissive yet human-seeking behaviour is indeed species-specific, or rather results from biased human treatment during their life, and which specific mechanisms drove the likely bidirectional influence remains to be explored.

The ability to respond appropriately to predators is essential for survival. Because response options vary with predation context, anti-predator behavior is often flexible, context dependent and shaped by learning. Corvids engage in predator mobbing, which contains a vocal component (scolding) and predator-directed behaviors (approaches, attacks). Individuals typically gang up for mobbing and pass on information about predators; yet their expression of antipredator behavior is influenced by factors such as social status, age, and rearing conditions. Here we investigated the development of antipredator behavior in ravens, specifically the onset of mobbing and the extent to which these responses are affected by parental agitation. We exposed 12 captive families to a potentially dangerous human (DH) at two stages of offspring development: shortly after fledging and near independence. We tested the hypotheses that (i) parents are more protective when the offspring are young and that (ii) offspring show more predator-directed behaviors with increasing age. We found that (i) adults mobbed significantly more during the early test period and (ii) offspring were less likely to ignore the DH and showed increased engagement during the late test period. These findings suggest that parental anti-predator investment diminishes as offspring develop greater motoric and cognitive abilities. This reduced investment may encourage offspring to independently assess and respond to threats. Yet, they hardly engage in mobbing while they are with their parents. Future studies may clarify if the increase in offsprings’ interindividual variance in both mobbing components are indicative for the emergence of individuality.

Cognitive abilities can promote acclimation to life in cities. However, the genetic versus environmental drivers of cognition have rarely been studied in the wild and there exists a major knowledge gap concerning the role of cognition in adaptation to urban contexts. We evaluate cognitive variation in wild great tits (Parus major; N = 393) along an urban gradient, and estimate the genetic basis of this variation using a combination of a common garden experiment, quantitative genetic analysis, and genome-wide association study. Specifically, we measure inhibitory control abilities which affect how animals respond to novel challenges. We find that wild urban and forest tits do not clearly differ in inhibitory control performance (number of errors or the latency to escape) during a motor detour task; a result that was consistent in birds from urban and forest origins reared in a common garden (N = 73) despite average performance differing between wild and captive birds. Cognitive performance was repeatable (R = 0.35–0.38) and showed low to moderate heritability in the wild (h² = 0.16–0.28, but both estimates had high uncertainty). We identified five SNPs that were associated with the number of errors during the task, with two of these SNPs linked to genes related to serotonergic and dopaminergic systems that are known to play important roles in cognition. Altogether, our study finds limited evidence that inhibitory control abilities have evolved under novel urban contexts, yet reveals some evidence for a genetic basis of this cognitive trait in great tits.