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Gaze cues play a vital role in conveying critical information about objects and locations necessary for survival, such as food sources, predators, and the attentional states of conspecific and heterospecific individuals. During referential intentional communication, the continuous alternation of gaze between a communicative partner and a specific object or point of interest attracts the partner's attention towards the target. This behaviour is considered by many as essential for understanding intentions and is thought to involve mental planning. Here, we investigated the behavioural responses of seven bottlenose dolphins ( Tursiops truncatus ) that were given an impossible task in the presence of two experimenters (a 'commanding experimenter' and a 'non-commanding experimenter'), whose attentional state towards the dolphins varied. We found that the dolphins spontaneously displayed gaze alternation, specifically triadic referential pointing, only when the human commanding experimenter was facing them. However, they ceased to alternate their gaze between the impossible object and the commanding experimenter when the experimenter had their back turned. Notably, the dolphins' behaviour differed from general pointing and gaze, as their triadic sequence occurred within a narrow time window. These findings suggest that the dolphins were sensitive to human attentional cues and utilized their own gaze cue (pointing) as a salient signal to attract the attention of the commanding experimenter towards a specific location., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2024 The Author(s).)

Animal vocalisations encode a wide range of biological information about the age, sex, body size, and social status of the emitter. Moreover, vocalisations play a significant role in signalling the identity of the emitter to conspecifics. Recent studies have shown that, in the African penguin (Spheniscus demersus), acoustic cues to individual identity are encoded in the fundamental frequency (F 0 ) and resonance frequencies (formants) of the vocal tract. However, although penguins are known to produce vocalisations where F 0 and formants vary among individuals, it remains to be tested whether the receivers can perceive and use such information in the individual recognition process. In this study, using the Habituation-Dishabituation (HD) paradigm, we tested the hypothesis that penguins perceive and respond to a shift of ± 20% (corresponding to the natural inter-individual variation observed in ex-situ colonies) of F 0 and formant dispersion (ΔF) of species-specific calls. We found that penguins were more likely to look rapidly and for longer at the source of the sound when F 0 and formants of the calls were manipulated, indicating that they could perceive variations of these parameters in the vocal signals. Our findings provide the first experimental evidence that, in the African penguin, listeners can perceive changes in F 0 and formants, which can be used by the receiver as potential cues for the individual discrimination of the emitter., (© 2023. The Author(s).)

Mirror exposure elicits a wide range of behavioral responses, some of which have been considered as part of possible evidence of mirror self-recognition (MSR). These responses can range from social behaviors, indicating that an animal considers its own reflection as a conspecific, to mirror-guided and self-directed actions. Evidence of MSR has been found categorically in only a few species, such as in magpies, chimpanzees, horses, and elephants. Evidence in corvids is currently debated due to inconsistent findings. In this study, we investigated the reaction of Eurasian jays when presenting them with three mirror-stimulation tasks. Based on the overall behavioral patterns across these three tasks, conclusions about birds' understanding of a reflective surface, and their perception of the reflection as either themselves or as a conspecific, appear premature. We highlight how the high neophobia of corvids and other methodological constraints might have hindered the likelihood to approach and explore a mirror, preventing the emergence of behaviors typically associated with MSR. Furthermore, we discuss how motivational factors, methodological constraints and species differences should be considered when interpreting behavioral responses to mirrors., Competing Interests: The authors declare there are no competing interests., (©2023 Baciadonna et al.)

Episodic memory involves the conscious recollection of personally experienced events, which has often been argued to be a uniquely human ability. 1-5 However, evidence for conscious episodic recall in humans is centered around language-based reports. With no agreed upon non-linguistic behavioral makers of consciousness, 6 episodic-like memory 7 therefore represents the behavioral characteristics of human episodic memory, in the absence of evidence for subjective experience during recall. Here, we provide compelling evidence for episodic-like memory in common bottlenose dolphins (Tursiops truncatus), based on the incidental encoding and unexpected question paradigm. 8 This methodology aims to capture the incidental encoding characteristic of human episodic memory, in that when we recall an experience, we remember information that was trivial at the time of encoding, but was encoded automatically. 9 We show that dolphins are able to use incidentally encoded spatial ("where") and social ("who") information to solve an unexpected memory task, using only a single test trial per test type, which ensured that the dolphins did not have the opportunity to semantically learn "rules" to pass the test. All participating dolphins made correct choices in both the "where" and "who" tests. These results suggest that dolphins are capable of encoding, recalling, and accessing incidental information within remembered events, which is an ability indicative of episodic memory in humans. We argue that the complex socio-ecological background of dolphins may have selected for the ability to recall both spatial and social information in an episodic-like manner., Competing Interests: Declaration of interests The authors declare no competing interests., (Copyright © 2022 The Author(s). Published by Elsevier Inc. All rights reserved.)

Large-brained birds, such as corvids and parrots, tend to fail tests for self-recognition (mirror self-recognition [MSR]), but the limited positive evidence for MSR in these species has been questioned due to methodological limitations. In the present study, we aimed to investigate MSR in ravens by performing three mirror tests: a mirror exposure test, a mirror preference test, and a mark test. Across all three tests, the ravens' behavior was not consistent with MSR. Three out of six ravens infrequently interacted with the mirror and the nonmirror surfaces. Two birds explored the mirror and occasionally displayed contingent behaviors. Finally, the ravens made very few social displays toward the mirror, suggesting that at this stage they did not treat their reflection as a conspecific. These findings, along with the current evidence available, raise further questions on the validity of relying on one test to establish self-recognition and call for the development of methods beyond mirror tests to explore self-recognition in nonhuman animals. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

The ability to vary the characteristics of one's voice is a critical feature of human communication. Understanding whether and how animals change their calls will provide insights into the evolution of language. We asked to what extent the vocalizations of penguins, a phylogenetically distant species from those capable of explicit vocal learning, are flexible and responsive to their social environment. Using a principal components (PCs) analysis, we reduced 14 vocal parameters of penguin's contact calls to four PCs, each comprising highly correlated parameters and which can be categorized as fundamental frequency, formant frequency, frequency modulation, and amplitude modulation rate and duration. We compared how these differed between individuals with varying degrees of social interactions: same-colony versus different-colony, same colony over 3 years and partners versus non-partners. Our analyses indicate that the more penguins experience each other's calls, the more similar their calls become over time, that vocal convergence requires a long time and relative stability in colony membership, and that partners' unique social bond may affect vocal convergence differently than non-partners. Our results suggest that this implicit form of vocal plasticity is perhaps more widespread across the animal kingdom than previously thought and may be a fundamental capacity of vertebrate vocalization.

Mirror tasks can be used to investigate whether animals can instrumentally use a mirror to solve problems and can understand the correspondence between reflections and the real objects they represent. Two bird species, a corvid (New Caledonian crow) and a parrot (African grey parrot), have demonstrated the ability to use mirrors instrumentally in mirror-mediated spatial locating tasks. However, they have not been challenged with a mirror-guided reaching task, which involves a more complex understanding of the mirror's properties. In the present study, a task approximating the mirror-guided reaching task used in primate studies was adapted for, and given to, a corvid species (Eurasian jay) using a horizontal string-pulling paradigm. Four birds learned to pull the correct string to retrieve a food reward when they could see the food directly, whereas none used the reflected information to accomplish the same objective. Based on these results, it cannot be concluded whether these birds understand the correspondence between the location of the reward and its reflected information, or if the relative lack of visual-perceptual motor feedback given by the setup interfered with their performance. This novel task is posited to be conceptually more difficult compared to mirror-mediated spatial locating tasks, and should be used in avian species that have previously been successful at using the mirror instrumentally. This would establish whether these species can still succeed at it, and thus whether the task does indeed pose additional cognitive demands., (© 2021. The Author(s).)

Brain lateralization is generally considered adaptive for an individual and it can be ascertained, for example, by measuring the preferential use of limbs. Avian models have been extensively used to investigate the evolution and the advantages of brain lateralization. Birds of prey are a good model to study motor laterality, however to date they have been studied almost exclusively in the context of predatory behaviour. In this study, we tested lateralization in Gyrfalcon ( Falco rusticolus ) across multiple contexts, and collected the following measures:(1) standing leg preference when sleeping, (2) wing preference to position the head while sleeping and (3) leg preference to grasp food. At the population level, we found left-leg lateralization while sleeping and no preference for placing the head under the left or the right wing. In the context of the predatory behaviour, we found a trend towards using the left leg to grasp food. Across the behaviours observed, we did not find evidence of lateralization at an individual level, as most of the subjects were ambidextrous. This study highlights the importance of the behavioural context when investigating side-bias and hemispheric laterality.

The stability of individual acoustic features is fundamental in social species, and more importantly in monogamous and territorial species, showing long-term fidelity both to the partner and the breeding site. In this study, the stability over time of two discrete vocal types was investigated in the African penguin (Spheniscus demersus), a monogamous and territorial seabird. Contact calls and ecstatic display songs were recorded from an ex situ colony in 2017 and in 2020. For each vocalisation, we measured 14 spectral and temporal acoustic parameters related to both source and filter components. Two separate leave-one-out cross-validated Discriminant Function Analyses (DFA) were then performed, generating the discriminant functions from the vocalisations collected in 2017 to classify those recorded in 2020. The DFA correctly classified 62% of the contact calls (10 subjects) and 80.9% of the ecstatic display songs (seven subjects) according to the correct emitter, showing that acoustic cues to individuality encoded in both vocal types remained unchanged over four consecutive breeding seasons. We suggest that, in this monogamous and territorial bird species, individual acoustic stability could be selected for to identify groupmates and neighbours over the years and to help couples to reunite in consecutive breeding seasons, increasing individual fitness., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

An animal's ability to recognize another individual by matching their image to their voice suggests they form internal representations of other individuals. To what extent this ability, termed cross-modal individual recognition, extends to birds other than corvids is unknown. Here, we used an expectancy violation paradigm to determine whether a monogamous territorial seabird ( Spheniscus demersus ) can cross-modally recognize familiar conspecifics (partners or colony-mates). After pairs of penguins spent time together in an isolated area, one of the penguins was released from the area leaving the focal penguin alone. Subsequently, we played contact calls of the released penguin (congruent condition) or a different penguin (incongruent condition). After being paired with a colony-mate, focal penguins' response latency to the auditory stimulus was faster in the incongruent compared to congruent condition, indicating the mismatch violated their expectations. This behavioural pattern was not observed in focal penguins after being paired with their partner. We discuss these different results in the light of penguins' natural behaviour and the evolution of social communication strategies. Our results suggest that cross-modal individual recognition extends to penguins and reveals, in contrast with previously thought, that social communication between members of this endangered species can also use visual cues.

Pioneering research on avian behaviour and cognitive neuroscience have highlighted that avian species, mainly corvids and parrots, have a cognitive tool kit comparable with apes and other large-brained mammals, despite conspicuous differences in their neuroarchitecture. This cognitive tool kit is driven by convergent evolution, and consists of complex processes such as casual reasoning, behavioural flexibility, imagination, and prospection. Here, we review experimental studies in corvids and parrots that tested complex cognitive processes within this tool kit. We then provide experimental examples for the potential involvement of metacognitive skills in the expression of the cognitive tool kit. We further expand the discussion of cognitive and metacognitive abilities in avian species, suggesting that an integrated assessment of these processes, together with revised and multiple tasks of mirror self-recognition, might shed light on one of the most highly debated topics in the literature-self-awareness in animals. Comparing the use of multiple assessments of self-awareness within species and across taxa will provide a more informative, richer picture of the level of consciousness in different organisms.

Obesity is associated with difficulties due to stigma and loneliness. These impact negatively on individuals' quality of life and behaviour change efforts. Increased sensitivity to others' negative feedback might play a role in the maintenance of these difficulties and could be addressed in psychological interventions. We conducted a systematic review of interpersonal difficulties in individuals with obesity, across the lifespan. We investigated early interpersonal adversity (i.e. frequency of teasing/bullying), perceived interpersonal stress and quality of social life, based on a rejection sensitivity model. The databases PubMed, Web of Knowledge and AGRIS, Embase, Medline and PsychINFO were searched for published peer-reviewed journal articles (1980-June 2018). Thirty-two studies met inclusion criteria. Results from the meta-analyses (n = 16 studies) indicated that overweight/obese individuals reported more frequent experiences of teasing/bullying, greater interpersonal stress and poorer quality of social life than healthy weight individuals. Findings in the systematic review aligned to this evidence. Psychological interventions targeting increased sensitivity to negative interpersonal feedback could improve interpersonal functioning and, in turn, eating behaviours in individuals with obesity., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Background: Evidence from humans suggests that the expression of emotions can regulate social interactions and promote coordination within a group. Despite its evolutionary importance, social communication of emotions in non-human animals is still not well understood. Here, we combine behavioural and physiological measures, to determine if animals can distinguish between vocalisations linked to different emotional valences (positive and negative). Using a playback paradigm, goats were habituated to listen to a conspecific call associated with positive or negative valence (habituation phase) and were subsequently exposed to a variant of the same call type (contact call) associated with the opposite valence (dishabituation phase), followed by a final call randomly selected from the habituation phase as control (rehabituation phase). The effects of the calls on the occurrence of looking and cardiac responses in these phases were recorded and compared., Results: We found that when the valence of the call variant changed, goats were more likely to look at the source of the sound, indicating that they could distinguish calls based on their valence. Heart rate was not affected by the valence of the calls played, whereas heart-rate variability tended to be higher in the habituation and rehabituation phases, when positive calls were played compared to negative ones. Together, the behavioural and physiological measures provide evidence suggesting, first, that goats are able to distinguish call variants based on their valence, and second, that goat behaviour and cardiac responses are affected by call valence., Conclusion: This study indicates that auditory modalities are a potent means to communicate emotions in non-human animals. These findings can contribute to our understanding of the evolution of emotion perception in non-human animals., Competing Interests: Competing interestsThe authors declare that they have no competing interests.

Functional asymmetries, for example, the preferential involvement of 1 brain hemisphere to process stimuli, may increase brain efficiency and the capacity to carry out tasks simultaneously. We investigated which hemisphere was primarily involved in processing acoustic stimuli in goats using a head-orienting paradigm. Three playbacks using goat vocalizations recorded in different contexts: food anticipation (positive), isolation (negative), food frustration (negative), as well as 1 playback involving dog barks (negative) were presented on the left and right sides of the test subjects simultaneously. The head-orienting response (left or right) and latency to resume feeding were recorded. The direction of the head-orienting response did not differ between the various playbacks. However, when the head-orienting response was tested against chance level, goats showed a right bias regardless of the stimuli presented. Goats responded more to dog barks than to food frustration calls, whereas responses to food anticipation and isolation calls were intermediate. In addition, the latency to resume feeding, an indicator of fear reaction, was not affected by the kind of vocalization presented. These results provide evidence for asymmetries in goat vocal perception of emotional-linked conspecific and heterospecific calls. They also suggest involvement of the left brain hemisphere for processing acoustic stimuli, which might have been perceived as familiar and non-threatening.

Emotions can be defined as an individual's affective reaction to an external and/or internal event that, in turn, generates a simultaneous cascade of behavioral, physiological, and cognitive changes. Those changes that can be perceived by conspecifics have the potential to also affect other's emotional states, a process labeled as "emotional contagion." Especially in the case of gregarious species, such as livestock, emotional contagion can have an impact on the whole group by, for instance, improving group coordination and strengthening social bonds. We noticed that the current trend of research on emotions in livestock, i.e., investigating affective states as a tool to assess and improve animal welfare, appears to be unbalanced. A majority of studies focuses on the individual rather than the social component of emotions. In this paper, we highlight current limitations in the latter line of research and suggest a stronger emphasis on the mechanisms of how emotions in livestock are transmitted and shared, which could serve as a promising tool to synergistically enhance the welfare of all individuals within a group.

Behavioural lateralization consists of perceptual and motor lateralization and provides adaptive advantages such as a general increase in brain efficiency. Motor laterality refers to the preferred use of either left or right limbs or organs to perform a specific task. We investigated motor laterality in goats (Capra hircus), using the First-stepping Task. During this task, the first foreleg used to step off a board after standing with both forelimbs was recorded. Subjects varied individually in their expression of motor lateralization with 36.6% of subjects showing individual-level asymmetries. However, goats as a group did not show a preference for a specific foreleg or lateralization in general. Our results support the hypothesis that the need to coordinate behaviour among conspecifics might be important for determining the presence of lateralization at the population level. We suggest that future research investigates how social complexity might affect population-level asymmetries, and whether stimuli with high emotional valence impact on lateralization presence and level (i.e., individual or population).

Until recently, whether invertebrates might exhibit emotions was unknown. This possibility has traditionally been dismissed by many as emotions are frequently defined with reference to human subjective experience, and invertebrates are often not considered to have the neural requirements for such sophisticated abilities. However, emotions are understood in humans and other vertebrates to be multifaceted brain states, comprising dissociable subjective, cognitive, behavioural and physiological components. In addition, accumulating literature is providing evidence of the impressive cognitive capacities and behavioural flexibility of invertebrates. Alongside these, within the past few years, a number of studies have adapted methods for assessing emotions in humans and other animals, to invertebrates, with intriguing results. Sea slugs, bees, crayfish, snails, crabs, flies and ants have all been shown to display various cognitive, behavioural and/or physiological phenomena that indicate internal states reminiscent of what we consider to be emotions. Given the limited neural architecture of many invertebrates, and the powerful tools available within invertebrate research, these results provide new opportunities for unveiling the neural mechanisms behind emotions and open new avenues towards the pharmacological manipulation of emotion and its genetic dissection, with advantages for disease research and therapeutic drug discovery. Here, we review the increasing evidence that invertebrates display some form of emotion, discuss the various methods used for assessing emotions in invertebrates and consider what can be garnered from further emotion research on invertebrates in terms of the evolution and underlying neural basis of emotion in a comparative context., Competing Interests: Competing interestsThe authors declare no competing or financial interests., (© 2017. Published by The Company of Biologists Ltd.)

When identifying other individuals, animals may match current cues with stored information about that individual from the same sensory modality. Animals may also be able to combine current information with previously acquired information from other sensory modalities, indicating that they possess complex cognitive templates of individuals that are independent of modality. We investigated whether goats ( Capra hircus ) possess cross-modal representations (auditory-visual) of conspecifics. We presented subjects with recorded conspecific calls broadcast equidistant between two individuals, one of which was the caller. We found that, when presented with a stablemate and another herd member, goats looked towards the caller sooner and for longer than the non-caller, regardless of caller identity. By contrast, when choosing between two herd members, other than their stablemate, goats did not show a preference to look towards the caller. Goats show cross-modal recognition of close social partners, but not of less familiar herd members. Goats may employ inferential reasoning when identifying conspecifics, potentially facilitating individual identification based on incomplete information. Understanding the prevalence of cross-modal recognition and the degree to which different sensory modalities are integrated provides insight into how animals learn about other individuals, and the evolution of animal communication.

Animal emotional states can be investigated by evaluating their impact on cognitive processes. In this study, we used a judgement bias paradigm to determine if short-term positive human-animal interaction (grooming) induced a positive affective state in goats. We tested two groups of goats and trained them to discriminate between a rewarded and a non-rewarded location over nine training days. During training, the experimental group ( n = 9) was gently groomed by brushing their heads and backs for five min over 11 days (nine training days, plus two testing days, total time 55 min). During training, the control group ( n = 10) did not experience any direct interaction with the experimenter, but was kept unconstrained next to him for the same period of time. After successful completion of the training, the responses (latency time) of the two groups to reach ambiguous locations situated between the two reference locations (i.e., rewarded/non-rewarded) were compared over two days of testing. There was not a positive bias effect after the animals had been groomed. In a second experiment, 10 goats were tested to investigate whether grooming induced changes in physiological activation (i.e., heart rate and heart rate variability). Heart rate increased when goats were groomed compared to the baseline condition, when the same goats did not receive any contact with the experimenter. Also, subjects did not move away from the experimenter, suggesting that the grooming was positively accepted. The very good care and the regular positive contacts that goats received from humans at the study site could potentially account for the results obtained. Good husbandry outcomes are influenced by animals' perception of the events and this is based on current circumstances, past experiences and individual variables. Taking into account animals' individual characteristics and identifying effective strategies to induce positive emotions could increase the understanding and reliability of using cognitive biases paradigms to investigate and promote animal welfare., Competing Interests: The authors declare there are no competing interests.

Whether invertebrates exhibit positive emotion-like states and what mechanisms underlie such states remain poorly understood. We demonstrate that bumblebees exhibit dopamine-dependent positive emotion-like states across behavioral contexts. After training with one rewarding and one unrewarding cue, bees that received pretest sucrose responded in a positive manner toward ambiguous cues. In a second experiment, pretest consumption of sucrose solution resulted in a shorter time to reinitiate foraging after a simulated predator attack. These behavioral changes were abolished with topical application of the dopamine antagonist fluphenazine. Further experiments established that pretest sucrose does not simply cause bees to become more exploratory. Our findings present a new opportunity for understanding the fundamental neural elements of emotions and may alter the view of how emotion states affect decision-making in animals., (Copyright © 2016, American Association for the Advancement of Science.)

Introduction: The computational demands of sociality (maintaining group cohesion, reducing conflict) and ecological problems (extractive foraging, memorizing resource locations) are the main drivers proposed to explain the evolution cognition. Different predictions follow, about whether animals would preferentially learn new tasks socially or not, but the prevalent view today is that intelligent species should excel at social learning. However, the predictions were originally used to explain primate cognition, and studies of species with relatively smaller brains are rare. By contrast, domestication has often led to a decrease in brain size, which could affect cognition. In domestic animals, the relaxed selection pressures compared to a wild environment could have led to reduced social and physical cognition. Goats possess several features commonly associated with advanced cognition, such as successful colonization of new environments and complex fission-fusion societies. Here, we assessed goat social and physical cognition as well as long-term memory of a complex two-step foraging task (food box cognitive challenge), in order to investigate some of the main selection pressures thought to affect the evolution of ungulate cognition., Results: The majority of trained goats (9/12) successfully learned the task quickly; on average, within 12 trials. After intervals of up to 10 months, they solved the task within two minutes, indicating excellent long-term memory. The goats did not learn the task faster after observing a demonstrator than if they did not have that opportunity. This indicates that they learned through individual rather than social learning., Conclusions: The individual learning abilities and long-term memory of goats highlighted in our study suggest that domestication has not affected goat physical cognition. However, these cognitive abilities contrast with the apparent lack of social learning, suggesting that relatively intelligent species do not always preferentially learn socially. We propose that goat cognition, and maybe more generally ungulate cognition, is mainly driven by the need to forage efficiently in harsh environments and feed on plants that are difficult to access and to process, more than by the computational demands of sociality. Our results could also explain why goats are so successful at colonizing new environments.

Animals can use their environments more efficiently by selecting particular sources of information (personal or social), according to specific situations. Group-living animals may benefit from gaining information based on the behaviour of other individuals. Indeed, social information is assumed to be faster and less costly to use than personal information, thus increasing foraging efficiency. However, when food sources change seasonally or are randomly distributed, individual information may become more reliable than social information. The aim of this study was to test the use of conflicting personal versus social information in goats (Capra hircus), in a foraging task. We found that goats relied more on personal than social information, when both types of information were available and in conflict. No effect of social rank was found on the occasions when goats followed other demonstrator goats. Goats are selective browsers/grazers and therefore relying on personal rather than social information could be the most efficient way to find patchily distributed resources in highly variable environments. Studies testing specific assumptions regarding the use of different sources of information can extend our understanding of decision making, including observed patterns of social learning.

Cerebral lateralization is the portioning of the cognitive functions between the two cerebral hemispheres. Several factors, like embryological manipulations, light exposure, health conditions, sex and age can influence the left-right brain asymmetries and contribute to increasing the variability in the strength and direction of laterality within most species. We investigated the influence of an environmental constraint, namely space availability, as a new source of variation on laterality in an adult vertebrate model, the donkey. In a baseline condition we tested whether donkeys show a motor lateralization bias at population level, while in an experimental condition we manipulated space availability to verify if a reduction in this parameter could represent a new source of variation in laterality. Results show that donkeys are lateralized at population level with a strong bias to standing with the right forelimb advanced over the left and that a reduction of space availability is an important source of variation in the laterality strength and direction within this species. The comparative analysis of the environmental and developmental factors that give origin to neural and behavioural laterality in animal models will be very important for a better understanding of the evolutionary origin of such multifaceted phenomenon., (Copyright © 2011 Elsevier B.V. All rights reserved.)

Brain asymmetry--i.e. the specialisation of each cerebral hemisphere for sensorimotor processing mechanisms and for specific cognitive functions-is widely distributed among vertebrates. Several factors, such as embryological manipulations, sex, age, and breeds, can influence the maintenance, strength, and direction of laterality within a certain vertebrate species. Brain lateralisation is a universal phenomenon characterising not only cerebral control of cognitive or emotion-related functions but also cerebral regulation of somatic processes, and its evolution is strongly influenced by social selection pressure. Diseases are well known to be a cost of sociality but their role in influencing behaviour has received very little attention. The present study investigates the influence of illness conditions as a source of variation on laterality in a social keystone vertebrate predator model, the lion. In a preliminary stage, the clinical conditions of 24 adult lions were assessed. The same animals were scored for forelimb preference when in the quadrupedal standing position. Lions show a marked forelimb preference with a population bias towards the use of the right forelimb. Illness conditions strongly influenced the strength of laterality bias, with a significant difference between clinically healthy and sick lions. According to these results, health conditions should be recognised as an important source of variation in brain lateralisation.

Bats, in terms of variety of species and their absolute numbers, are the most successful mammals on earth. The anatomical and functional peculiarities of Microchiroptera are not confined only to the auditory system; the wings (hands) of bats are unique both from an anatomical point of view as from a sensorial one. They are much thinner than those of birds and their bony structure is much more similar to a primate hand than to the forelimb of other mammals of the bat's size; the thumb, is very small and on its distal end there is a little claw that bats use for crawling and manipulating food. However, despite this very frequent use of the hands for food catching and for walking, nothing is known about the existence of a preferential use of the hands in Microchiroptera. The present study investigates the existence of handedness in the Schreiber's Long-Fingered Bat by recording the preferential use of the hand while climbing the walls of a plastic cylinder. This bat species is lateralized at population level and shows a left forelimb bias when using hands for climbing/grasping. This result is the first evidence of population-level handedness in an echolocating bat species., (Copyright (c) 2010 Elsevier B.V. All rights reserved.)

Two categories of behaviour involving lateralized posture were observed in semi-natural conditions in ostriches (Struthio camelus). Observing preferences for left or right foot, both in the forward foot posture (the foot standing in front at rest) and the starting foot used to initiate locomotion, a population-level right-foot preference was shown for the whole group and for each of the three age ranges considered (chick, young and adult). Ostriches are known to rely upon a lateralized behaviour during hatching (using their right foot to break the egg shell) suggesting the hypothesis that the precocious motor laterality observed at hatching might stand as a precursor of limb preference later in development, as already observed in other avian species., (2009 Elsevier B.V. All rights reserved.)