acta ethologica最新文献

This case study presents the first documented in situ observation of parturition in the wild camel (Camelus ferus). Despite extensive research on domesticated camelids, virtually nothing is known about parturition and early maternal behaviour in their wild relatives. On 19 April 2025, a female wild camel was observed under semi-natural conditions in the buffer zone of the Great Gobi A Strictly Protected Area (Mongolia). Continuous focal sampling captured the entire birth process, including labour progression, maternal-neonatal interactions, calf standing and suckling milestones, and post-parturition protective behaviour. The dam displayed active assistance during labour, immediate postnatal contact, and strong protective instincts – guarding the calf from conspecifics as well as other species. The calf stood within 25 min and suckled within 37 min, suggesting an adaptive need for rapid mobility in an open, predator-exposed landscape. These findings confirm key reproductive traits observed in domesticated camels but also reveal behaviourally specific adaptations to wild desert environments. Given the species’ slow reproduction rate and environmental vulnerability, detailed behavioural insights from even single-case studies offer critical guidance for both in situ conservation and captive breeding protocols. Observations provide crucial insight into a previously undocumented stage of the wild camel’s life history. By comparing observed behaviour to existing domestic data, we begin to fill a key gap in the reproductive ethology of this endangered species.

Applying widely used tasks to test the problem solving of species with distinct ecological and social structures facilitates a comprehensive understanding of selective pressures for cognitive traits, such as insight, innovation, and causal reasoning. A southern ground hornbill (Bucorvus leadbeateri) was presented with a version of the Aesop’s Fable task to extend explorations of problem solving in this paradigm to a species that has heretofore been understudied. After learning to perform the task, our subject was presented with a version in which heavy stones were more efficient than light stones in displacing a water column to bring food rewards within reach. Although she successfully retrieved rewards more quickly across sessions and learned to select, lift, and drop stones into the tube, she did not preferentially select heavy stones to complete the task, performing similarly to previously tested species. Despite the single subject not demonstrating any causal understanding of the property of weight in this task, the results demonstrate that hornbills will engage with novel object manipulation tasks and do not preclude the possibility that hornbills could evidence such understanding. Gaining a better understanding of the cognitive abilities of southern ground hornbills may ultimately contribute to improving husbandry and conservation efforts in this vulnerable species.

Animal personality, defined as consistent individual differences in behaviour across time and contexts, can significantly influence fitness and survival. However, the expression and stability of personality traits across ontogeny remain poorly understood, particularly in species undergoing complex life history transitions. Here, we examined behavioural consistency in juvenile two-spotted goby (Pomatoschistus flavescens) during the critical shift from a pelagic to a benthic lifestyle. Using two standardised assays—the emergence test (boldness) and open field test (exploration)—we assessed behavioural repeatability across repeated trials in a laboratory setting. Across most behavioural measures, we found low repeatability, with within-individual variance exceeding among-individual variance. Correlation analyses revealed consistent behavioural responses within contexts (e.g., among boldness measures), but no significant cross-context correlations, indicating that boldness and exploration do not form a behavioural syndrome in juveniles. These results contrast with findings in adult gobies and suggest that stable personality traits may not be present at this developmental stage. We propose that the observed behavioural flexibility may be adaptive, allowing juveniles to respond rapidly to the variable environmental and social conditions encountered during post-settlement. This ontogenetic plasticity may confer survival advantages in dynamic reef environments. Our findings underscore the importance of incorporating life stage and developmental context when investigating animal personality and behavioural organisation.

Bioacoustics is essential to understand patterns of vocalization in anuran amphibians, including their advertisement, aggressive, and distress calls. Aggressive and distress calls occur when the individuals are threatened and present a strong phylogenetic signal, being potential taxonomic markers, especially for cryptic species. The genus Pithecopus includes 12 species of arboreal frogs, including the cryptic species P. nordestinus and P. gonzagai, two sympatric species that can be differentiated based on genetic, morphological, and acoustic features. This study describes and compares the distress calls of P. gonzagai and P. nordestinus, analyzing acoustic differences and the relationship with their advertisement call. We conducted field work at the Tapacurá Ecological Station, Pernambuco, Brazil, where the distress calls of three males of P. gonzagai were recorded. We compared with data on P. nordestinus, obtained from the Fonoteca Netotropical Jacques Vielliard. The results show that distress calls are longer, with higher frequency, and are more complex than advertisement calls, for both species. Moreover, there is a marked contrast for both calls between the two species, especially when considering distress call duration, with P. nordestinus emitting longer calls. Distress calls are still an understudied type of vocalization, despite being observed in many species. These results suggest that both ecological and evolutionary factors may have a role in shaping the vocalization of anurans, reinforcing the importance of bioacoustics for the systematics and conservation of Neotropical amphibians.

Living in complex social environments presents behavioural and cognitive challenges. A key challenge is the regulation of aggression, which may be facilitated by response inhibition, the ability to suppress inappropriate actions. In more complex social environments, greater variability in interactions may increase demands for aggression regulation, promoting the development of response inhibition. However, social instability, a form of complexity characterised by frequent changes in group composition, can elevate aggression and may instead impair inhibition. To test these competing predictions, we raised 144 chickens (Gallus gallus domesticus) in either stable or unstable social groups for five weeks. We observed the aggression within their enclosures following the final manipulation and assessed their response inhibition using a thwarting task and a cylinder task. Unstable groups initially showed more aggression than stable groups following regrouping, but this declined rapidly to the same lower level of aggression as the stable groups. Contrary to our predictions, there were no differences between birds raised in stable and unstable groups for any measure of response inhibition, and individual variation in aggression did not correlate with inhibitory performance. These findings suggest that social instability influences aggression but does not affect the development of response inhibition in chickens, highlighting the potential context- and species-specific nature of social effects on cognition.

The Japanese giant flying squirrel is an arboreal mammal that mainly eats tree leaves. Some individuals first fold the leaf in half along the midvein using the mouth and next fold it vertically with the snout while holding the leaf with the forepaw. After partial eating of the corner of the folded leaf, they drop it on the ground. This leaf debris has an eaten hole in the center. We examined such leaf debris from six areas in Japan and found that the hole was usually located on the widest part of the leaf: near the tip of apically broad leaves, the middle of centrally broad leaves, and the base of basally broad leaves. This feeding behavior can be compared to the paper craft origami. We generated a paper leaf model with a clip that resembled the flying squirrel’s forepaw and found that the paper model is folded most compactly when clipped at the widest point along midvein. The compactly folded paper facilitates the next vertical folding. Thus, the flying squirrels learn the physical properties of leaves and make a fold at the widest part of the leaf, just like in origami.

The genus Dopasia (Anguidae), native to Southeast Asia, remains poorly studied due to its elusive and secretive lifestyle; therefore, any information on its ecology and behaviour is particularly valuable. Here we present the first detailed observations of male-male combat in the genus, specifically documented in Dopasia harti (Boulenger, 1899) from Taiwan, based on unique photographic and video evidence. While male-male combat is well documented across various squamates, records from the family Anguidae are scarce and virtually absent for Dopasia. We therefore compare the ritualized behaviours observed in D. harti with those previously described in Anguis and Pseudopus. Finally, our study highlights the role of citizen science platforms in advancing field observations, biodiversity documentation, and herpetological knowledge.

Interactions between predators and prey have direct effects on the fitness of both parties. Particularly, lizards are predated by a wide variety of taxa, where birds have been proposed to exert a minor predation pressure than other vertebrates, like squamates. In general, cases among the literature report predation events where a single individual has been consumed. Here, we report the finding of seven lizards in the stomach content of a variable hawk (Geranoaetus polyosoma) road-killed in Arid Patagonia. The remains found included three adult individuals and two juveniles of Liolaemus morandae, and one adult of L. kingii, along with an additional tail. All remains showed a similar degree of digestion, which may indicate that lizards were consumed within a short timeframe. This novel finding represents the first confirmed evidence of a raptor preying simultaneously upon multiple lizard species and highlights the potential importance of lizards as dietary items of the variable hawk during the warm season in arid environments of Patagonia. Additionally, it is the first confirmed record of predation upon the Liolaemus lineomaculatus section, a group restricted to Patagonia. This predation event, including several individuals, suggests that predation pressure exerted by birds upon lizards may be underestimated, particularly in regions where other predators are scarce. We provide new information with implications for both lizard population dynamics and raptor foraging ecology, enhancing our knowledge on predator-prey interactions in Arid Patagonia.

Play behaviour in adult animals is often overlooked, particularly in free-ranging populations where it occurs less frequently than in juveniles. We investigated play behaviour and its associated behavioural sequences in urban-dwelling colonies of adult yellow mongooses (Cynictis penicillata), a species in which play has not previously been described. Using direct observations and continuous video footage, we quantified the occurrence and types of play, identified accompanying play signals and analysed the behaviours preceding and following play bouts. Play was consistently present across colonies, with social play being more frequent than either locomotor or object play. Play sessions typically began with identifiable play invitations, including play bows, which were often followed by nape bites. Behavioural sequences were analysed to describe the typical flow of actions in play events and revealed consistent patterns within and across colonies. Vigilance behaviour was more commonly observed following play bouts, suggesting a potential shift in attentional state. Our study provides one of the first detailed accounts of play in this species and contributes to a growing body of descriptive work on adult play in carnivores. These findings expand our understanding of the social behaviour of yellow mongooses and offer a baseline for future comparative studies.