Elodie F. Briefer

University of Copenhagen · Department of Biology

To group-living animals, such as most ungulates, being able to recognise the members of one’s social groups is crucial. While vocalisations often carry cues to identity, they are also impacted by the affective state of the caller, with signals often becoming more chaotic in contexts of negative valence or high arousal. How might this influence voca...

Bioacoustics and artificial intelligence facilitate ecological studies of animal populations

Acoustic signals are vital in animal communication, and quantifying them is fundamental for understanding animal behaviour and ecology. Vocalizations can be classified into acoustically and functionally or contextually distinct categories, but establishing these categories can be challenging. Newly developed methods, such as machine learning, can p...

Positive welfare is a relatively modern concept based on the idea that on the whole, an animal’s positive experiences should outweigh their negative ones. Intuitively, we therefore require indicators to measure when animals are experiencing positive and negative emotional states, as well as providing opportunities for animals to create positive exp...

Accurately estimating population sizes for free-ranging animals through noninvasive methods, such as camera trap images, remains particularly limited by small datasets. To overcome this, we developed a flexible model for estimating upper limit populations and exemplified it by studying a group-living synanthrope, the long-tailed macaque ( Macaca fa...

Acoustic signalling is a key mode of communication owing to its instantaneousness and rapid turnover, its saliency and flexibility and its ability to function strategically in both short- and long-range contexts. Acoustic communication is closely intertwined with both collective behaviour and social network structure, as it can facilitate the coord...

Because of the diverging needs of individuals, group life can lead to disputes and competition, but it also has many advantages, such as reduced predation risk, information sharing and increased hunting success. Social animals have to maintain group cohesion and need to synchronize activities, such as foraging, resting, social interactions and move...

Automated acoustic analysis is increasingly used in animal communication studies, and determining caller identity is a key element for many investigations. However, variability in feature extraction and classification methods limits the comparability of results across species and studies, constraining conclusions we can draw about the ecology and e...

How well does the information contained in vocal signals travel through the environment? To assess the efficiency of information transfer in little auk calls over distance, we selected two social call types with the highest potential for individuality coding among the social call types of the species. Using available recordings of known individuals...

For species maintaining long-term social bonds, particularly in complex networks such as dense colonies, vocal cues to identity can be crucial. Here, we investigated the vocal individuality within and across five call types of the little auk: a monogamous, colonial bird with a strong nest fidelity. Calls produced inside the nest over the incubation...

Animal vocalisations can often inform conspecifics about the behavioural context of production and the underlying affective states, hence revealing whether a situation should be approached or avoided. While this is particularly important for socially complex species, little is known about affective expression in wild colonial animals, and even less...

Simple Summary The European hedgehog is a generally welcomed but nowadays less common guest in residential gardens, as the species is in decline. Sharing habitats with humans comes at a cost: a residential garden holds many potential dangers for hedgehogs. Previous research has shown that certain models of robotic lawn mowers may harm hedgehogs. Th...

Source–filter theory posits that an individual's size and vocal tract length are reflected in the parameters of their calls. In species that mate assortatively, this could result in vocal similarity. In the context of mate selection, this would mean that animals could listen in to find a partner that sounds—and therefore is—similar to them. We inve...

Many seabird species breed in colonies counting up to hundreds of thousands of individuals. Life in such crowded colonies might require special coding–decoding systems to reliably convey information through acoustic cues. This can include, for example, developing complex vocal repertoires and adjusting the properties of their vocal signals to commu...

Dominance hierarchies help to reduce unnecessary fights and associated costs during the mating season. Fallow deer, Dama dama, typically have high levels of maleemale competition and strong reproductive skew. Nevertheless, how male dominance and daily fight rates affect mating success is still uncertain. We used a 2-year data set from a large popul...

Vocalizations constitute an effective way to communicate both emotional arousal (bodily activation) and valence (negative/positive). There is strong evidence suggesting that the convergence of vocal expression of emotional arousal among animal species occurs, hence enabling cross-species perception of arousal, but it is not clear if the same is tru...

Features varying more between than within individuals are considered as potential cues for individual recognition. According to the source‐filter theory of vocal production, the fundamental frequency of mammals' vocalizations depends on the characteristics of vocal folds, while Formants are determined by the characteristics of the vocal tract. Goat...

Background Discrimination and perception of emotion expression regulate interactions between conspecifics and can lead to emotional contagion (state matching between producer and receiver) or to more complex forms of empathy (e.g., sympathetic concern). Empathy processes are enhanced by familiarity and physical similarity between partners. Since he...

Features varying more between than within individuals are usually considered as potential cues for individual recognition. According to the source-filter theory of vocal production, the fundamental frequency of mammal's vocalisations depends on the characteristics of the vocal folds, while formants are determined by the characteristics of the vocal...

Dominance hierarchies help to reduce unnecessary fights and associated costs during the mating season. Fallow deer ( Dama dama ) typically have high levels of male-male competition and strong reproductive skew. Nevertheless, how male dominance and daily fight rates affect mating success remains unknown. We used a two-year dataset from a large popul...

Vocal expression of emotions has been observed across species and could provide a non-invasive and reliable means to assess animal emotions. We investigated if pig vocal indicators of emotions revealed in previous studies are valid across call types and contexts, and could potentially be used to develop an automated emotion monitoring tool. We perf...

Non-human primates (primates) are regarded as key research subjects for pre-clinical trials of several drugs aimed to alleviate human suffering. It has long been suggested that the predominant species in the international trade in live primates for use in research is the long-tailed macaque (Macaca fascicularis). However, little is still known abou...

The temporal structure of animals' acoustic signals can inform about context, urgency, species, individual identity, or geographical origin. We present three independent ideas to further expand the applicability of rhythm analysis for isochronous, that is, metronome-like, rhythms. A description of a rhythm or beat needs to include a description of...

Public concern for farm animal welfare is increasing. Animal welfare is defined as the balance of positive and negative emotions, where positive emotions are key to a good animal life. Emotion is defined as an experience that varies in valence and arousal. Many methods developed to identify positive emotions in animals involve disadvantages, for ex...

Stereotypies are common in captive animals, but it remains unclear if they are pathological by-products of captive conditions or if they have an adaptive function. Here, we address this question using crib-biting, a common type of stereotypic behaviour in domestic horses, thought to result from stressful or frustrating environments. Since chronic s...

Emotions guide behavioural decisions in response to events or stimuli of importance for the organism, and thus, are an important component of an animal’s life. Communicating emotions to conspecifics allows, in turn, the regulation of social interactions (e.g. approach and avoidance). The existence of common rules governing vocal expression of affec...

Animals are likely to appraise events as positive or negative based on their subjective perception, current state and past experiences. We tested the effects of anticipating positive (food anticipation), negative (inaccessible food) and neutral (clicker sound) events on behavioural and physiological responses of 30 goats. The experimental paradigm...

Emotions, unlike mood, are short-lived reactions associated with specific events. They can be characterized by two main dimensions, their arousal (bodily activation) and valence (negative versus positive). Knowledge of the valence of emotions experienced by domestic and captive animals is crucial for assessing and improving their welfare, as it ena...

Emotions, unlike mood, are short-lived reactions associated with specific events. They can be characterized by two main dimensions, their arousal (bodily activation) and valence (negative versus positive). Knowledge of the valence of emotions experienced by domestic and captive animals is crucial for assessing and improving their welfare, as it ena...

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...

Although stereotypic behaviors are a common problem in captive animals, why certain individuals are more prone to develop them remains elusive. In horses, individuals show considerable differences in how they perceive and react to external events, suggesting that this may partially account for the emergence of stereotypies in this species. In this...

Emotion expression plays a crucial role for regulating social interactions. One efficient channel for emotion communication is the vocal-auditory channel, which enables a fast transmission of information. Filter-related parameters (formants) have been suggested as a key to the vocal differentiation of emotional valence (positive versus negative) ac...

Functional asymmetries, e.g. the preferential involvement of one 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 vocalisati...

Stereotypies in animals are thought to arise from an interaction between genetic predisposition and sub-optimal housing conditions. In domestic horses, a well-studied stereotypy is crib-biting, an abnormal behaviour that appears to help individuals to cope with stressful situations. One prominent hypothesis states that animals affected by stereotyp...

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 contag...

Measuring emotions in nonhuman mammals is challenging. As animals are not able to verbally report how they feel, we need to find reliable indicators to assess their emotional state. Emotions can be described using two key dimensions: valence (negative or positive) and arousal (bodily activation or excitation). In this study, we investigated vocal e...

This corrects the article DOI: 10.1038/srep09989.

Communicating emotions to conspecifics (emotion expression) allows the regulation of social interactions (e.g. approach and avoidance). Moreover, when emotions are transmitted from one individual to the next, leading to state matching (emotional contagion), information transfer and coordination between group members are facilitated. Despite the hig...

Vocal expression of emotions has been suggested to be conserved throughout evolution. However, since vocal indicators of emotions have never been compared between closely related species using similar methods, it remains unclear whether this is the case. Here, we investigated vocal indicators of emotional valence (negative versus positive) in Przew...

Background Non-human animals often produce different types of vocalisations in negative and positive contexts (i.e. different valence), similar to humans, in which crying is associated with negative emotions and laughter is associated with positive ones. However, some types of vocalisations (e.g. contact calls, human speech) can be produced in both...

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...

In ewes, the ovulatory response of females exposed to familiar rams is lower than the response of those exposed to novel ones. In goats, males rendered sexually active by exposure to long days are more efficient to induce ovulation in seasonal anestrous females than untreated males. Two experiments were conducted to determine 1) whether male goats...

Individual recognition in gregarious species is fundamental in order to avoid misdirected parental investment. In ungulates, two very different parental care strategies have been identified: “hider” offspring usually lie concealed in vegetation whereas offspring of “follower” species remain with their mothers while they forage. These two strategies...

Individual recognition in gregarious species is fundamental in order to avoid misdirected parental investment. In ungulates, two very different parental care strategies have been identified: “hider” offspring usually lie concealed in vegetation whereas offspring of “follower” species remain with their mothers while they forage. These two strategies...

This study aimed to conduct a preliminary survey to investigate basic ownership factors, frequency of microchipping and insurance and views of pet rabbit owners on these areas and general rabbit management. More specifically, we aimed to investigate whether owners possess insurance, whether their rabbits are microchipped, and owners’ views on the r...

Modulation of the autonomic nervous system activity (ANS) allows animals to effectively respond to internal and external stimuli in everyday challenges via changes in for example, heart and respiration rate. Various factors, ranging from social such as dominance rank, to internal such as personality or affective states can impact on animal physiolo...

Background Mammal vocal parameters such as fundamental frequency (or pitch; fo) and formant dispersion often provide information about quality traits of the producer (e.g. dominance and body size), suggesting that they are sexually selected. However, little experimental evidence exists demonstrating the importance of these cues in intrasexual compe...

Studying vocal correlates of emotions is important to provide a better understanding of the evolution of emotion expression through cross-species comparisons. Emotions are composed of two main dimensions: emotional arousal (calm versus excited) and valence (negative versus positive). These two dimensions could be encoded in different vocal paramete...

Emotions are important because they enable the selection of appropriate behavioural decisions in response to external or internal events. Techniques for understanding and assessing animal emotions, and particularly positive ones, are lacking. Emotions can be characterized by two dimensions: their arousal (bodily excitation) and their valence (negat...

Machine learning techniques are becoming an important tool for studying animal vocal communication. The goat (Capra hircus) is a very social species, in which vocal communication and recognition are important. We tested the reliability of a Multi-Layer Perceptron (feed-forward Artificial Neural Network, ANN) to automate the process of classificatio...

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 preval...

Vocalizations encode a range of information about the caller, and variation in calling behavior and vocal structure may provide listeners with information about the motivation and condition of the caller. Fallow bucks only vocalize during the breeding season and can produce more than 3000 groans per hour. Males modulate their calling rates, calling...

Parallels between birdsong and human language are numerous and include particular temporal arrangements of acoustic units and the existence of dialects. In animal communication, modifications of the temporal ordering of existing acoustic units have rarely been clearly linked with changes in information content, particularly in a natural environment...

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 info...

http://onlinelibrary.wiley.com/doi/10.1111/jzo.12083/abstract We conducted a study of the male rut vocalizations (groans) of two closely related species, Persian and European fallow deer. Persian fallow deer are endangered, restricted to Iran and Israel, and their rut vocalizations have never been studied. By contrast, European fallow deer are one...

Research on animal temperament has increased significantly over recent years. Animal temperament is very similar to human personality, and is defined as individual differences that are consistent over time and between situations (Réale et al., 2007). There is some evidence suggesting that dogs physically resemble their owners (Roy and Christenfeld,...

Moods influence cognitive processes in that people in positive moods expect more positive events to occur and less negative ones (“optimistic bias”), whereas the opposite happens for people in negative moods (“pessimistic bias”). The evidence for an effect of mood on cognitive bias is also increasing in animals, suggesting that measures of optimism...

Polyandry is widespread, but its adaptive significance is not fully understood. The hypotheses used to explain its persistence have rarely been tested in the wild and particularly for large, long-lived mammals. We investigated polyandry in fallow deer, using female mating and reproduction data gathered over 10 years. Females of this species produce...

Number of matings by females and males and number of individuals involved in matings for each age class, over the 10 year study

Horses are often kept in individual stables, rather than in outdoor groups, despite such housing system fulfilling many of their welfare needs, such as the access to social partners. Keeping domestic stallions in outdoor groups would mimic bachelor bands that are found in the wild. Unfortunately, the high level of aggression that unfamiliar stallio...