Synergy between behavioural research on beluga whales (Delphinapterus leucas) conducted in zoological and wild settings

Behavioural observations of captive beluga whales have complemented and extended much of what has been learnt about this species in the wild. Aquarium-based research has provided finer-scale specificity for many topics, including the seasonal breeding pattern that is characteristic of this species, as well as socio-sexual behaviour that appears to be an important part of the behavioural repertoire of this species. One example is a strong propensity for male–male social interactions that begin to develop at an early age. In addition, detailed behavioural milestones in calves have been documented in ways that extend that which have been collected from wild populations. These include swim positions with mother, separations/reunions with mother, and other social interactions, and play. Characteristics of beluga maternal care have also been studied more often in captive settings than in the wild, particularly with respect to details pertaining to nursing behaviour, individual differences in maternal style and allomaternal care. Other topics that have received scientific scrutiny in zoological settings include individual differences and behavioural laterality. Thus, a greater understanding of beluga behavioural biology has the potential to emerge as a consequence of synergy between research conducted in the two settings.

Calibration-free 3D reconstruction of firefly trajectories from 360-degree cameras

Over the past few decades, progress in animal tracking techniques, from large migrating mammals to swarming insects, has facilitated significant advances in ecology, behavioural biology, and conservation science. Recently, we developed a technique to record and track flashing fireflies in their natural habitat using pairs of 360-degree cameras. The method, which has the potential to help identify and monitor firefly populations worldwide, was successfully implemented in various natural swarms. However, camera calibration remained tedious and time-consuming. Here, we propose and implement an algorithm that calibrates the cameras directly from the data, requiring minimal user input. We explain the principles of the calibration-free algorithm, and demonstrate the ease and efficiency of its implementation. This method is relatively inexpensive, versatile, and well-suited for automatic processing and the collection of a large dataset of firefly trajectories across species and populations. This calibration-free method paves the way to citizen science efforts for monitoring and conservation of firefly populations.

Mensch – Tier – Gott

The growing academic interest in animals and in their abilities and interactions with humans, along with insights from behavioural biology and philosophical reflections on animals, have led to a reassessment of the relationship between humans and animals—and this has had consequences for theology, which must investigate the philosophical and theological reasons why it largely ‘forgets about’ animals. Scripture and the spirituality of creation have the potential to shape our relationship to animals, and theologians must unlock this potential. We must walk a tightrope here: our task is to overcome the differentialism between humans and animals, but without blurring the specific characteristics of each. This book presents an interdisciplinary approach to a form of Christian animal ethics that is not seen as one isolated ethical field in philosophy or theology, but looks for answers in the debates about the relationship between human beings and animals. These questions concern the whole of society. With contributions by Andreas Aigner, Heike Baranzke, Martina Besler, Julia Blanc, Katharina Ebner, Matthias Eggel, Julia Enxing, Matthias Gauly, Herwig Grimm, Anita Idel, Kurt Kotrschal, Peter Kunzmann, Martin M. Lintner, Susana Monsó, Ute Neumann-Gorsolke, Jakob Ohm, Christina Potschka, Kurt Remele, Michael Rosenberger, Markus Vogt and Markus Wild.

On the Behavioural Biology of the Mainland Serow: A Comparative Study

Comparative behavioural studies help reconstruct the phylogeny of closely related species. In that respect, the serows Capricornis spp. occupy an important position as they have been assumed to be the closest forms to the ancestors of Caprinae. In spite of that, information on the behavioural repertoire of the mainland serow Capricornis sumatraensis is exceedingly poor. In this paper, we report data on the activity rhythms and social behaviour of rutting mainland serows in captivity (Central Thailand, January 1986; January–February 1987). Activity was bimodal with peaks in mid-afternoon and late night. Resting and ruminating peaked at noon and twilight. Four patterns of marking behaviour were observed out of a total of 1900 events. Males and females were found to use different marking sites and frequencies. A total of 33 social behaviour patterns were observed: 18 patterns concerned agonistic behaviour, whereas 15 patterns were relevant to courtship behaviour. A comparison across Caprinae species with unritualised piercing weapons (i.e., Capricornis, Naemorhedus, Rupicapra, Budorcas, and Hemitragus) has shown that inter-sexual direct forms of aggressive behaviour are used significantly more often than indirect ones, but for chamois, confirming Rupicapra spp. as the most advanced genus among them in terms of an early ritualisation of weapons. Conversely, horns of the goral Nemorhaedus spp. and the serow lie on the same plane of the frontal bones, thus making possible the usage of a dominance display through frontal pushing.

The optimal timing of teaching and learning across the life course

The evolutionary biologist W. D. Hamilton (Hamilton 1966 J. Theor. Biol. 12 , 12–45. ( doi:10.1016/0022-5193(66)90184-6 )) famously showed that the force of natural selection declines with age, and reaches zero by the age of reproductive cessation. However, in social species, the transfer of fitness-enhancing resources by postreproductive adults increases the value of survival to late ages. While most research has focused on intergenerational food transfers in social animals, here we consider the potential fitness benefits of information transfer, and investigate the ecological contexts where pedagogy is likely to occur. Although the evolution of teaching is an important topic in behavioural biology and in studies of human cultural evolution, few formal models of teaching exist. Here, we present a modelling framework for predicting the timing of both information transfer and learning across the life course, and find that under a broad range of conditions, optimal patterns of information transfer in a skills-intensive ecology often involve postreproductive aged teachers. We explore several implications among human subsistence populations, evaluating the cost of hunting pedagogy and the relationship between activity skill complexity and the timing of pedagogy for several subsistence activities. Long lifespan and extended juvenility that characterize the human life history likely evolved in the context of a skills-intensive ecological niche with multi-stage pedagogy and multigenerational cooperation. This article is part of the theme issue ‘Life history and learning: how childhood, caregiving and old age shape cognition and culture in humans and other animals’.

Vocal imitation can create acoustic attractors to guide mothers to pups in a crowded colony of Mexican free-tailed bats: A case-study of computational modelling in behavioural biology

How can we understand vocal imitation, the rare ability of certain species to copy vocalizations and other environmental sounds? How can computational modelling assist us? Here we describe a step-by-step process of mutually accommodating biological data to an implemented computational model. We begin with observations of harbour seals and with a putative computational model of their vocalizations in a colony. At each point in the development of the model, we analyse our decisions from the perspective of a materialist theory of knowledge, drawing on its explicit claims regarding abstraction and the concepts of the abstract universal, the concrete universal and the biological totality. We are eventually led to focus on bats, specifically the Mexican free-tailed bat (Tadarida brasiliensis mexicana). A large colony is a pandemonium of visual, olfactory and auditory cues to a pup’s location. Our computational model shows that if each pup’s vocalizations are influenced by its neighbours, robust attractors develop in the soundscape across the colony. Vocal imitation radically simplifies the problem of a returning mother finding a particular pup. She need only ascend the gradient of similarity with her own infant’s vocalization. This strategy outperforms other simple spatial search strategies and yields a parsimonious explanation for the role of vocal imitation in bats. We reach this modelling conclusion in a principled and transparent manner.

Proximity sensors on common noctule bats reveal evidence that mothers guide juveniles to roosts but not food

Female bats of temperate zones often communally rear their young, which creates ideal conditions for naive juveniles to find or learn about resources via informed adults. However, studying social information transfer in elusive and small-bodied animals in the wild is difficult with traditional tracking techniques. We used a novel ‘next-generation’ proximity sensor system (BATS) to investigate if and how juvenile bats use social information in acquiring access to two crucial resources: suitable roosts and food patches. By tracking juvenile–adult associations during roost switching and foraging, we found evidence for mother-to-offspring information transfer while switching roosts but not during foraging. Spatial and temporal patterns of encounters suggested that mothers guided juveniles between the juvenile and the target roost. This roost-switching behaviour provides evidence for maternal guidance in bats, a form of maternal care that has long been assumed, but never documented. We did not find evidence that mothers guide the offspring to foraging sites. Foraging bats reported brief infrequent meetings with other tagged bats that were best explained by local enhancement. Our study illustrates how this recent advance in automated biologging provides researchers with new insights into longstanding questions in behavioural biology.

The role of familiarity in signaller–receiver interactions

In animal communication, individuals of species exhibiting individual recognition of conspecifics with whom they have repeated interactions, receive signals not only from unfamiliar conspecifics, but also from individuals with whom they have prior experience. Empirical evidence suggests that familiarity with a specific signaller aids receivers in interpreting that signaller's signals, but there has been little theoretical work on this effect. Here, we develop a Bayesian decision-making model and apply it to the well-studied systems of primate ovulation signals. We compare the siring probability of learner males versus non-learner males, based on variation in their assessment of the best time to mate and mate-guard females. We compare males of different dominance ranks, and vary the number of females, and their cycle synchrony. We find strong fitness advantages for learners, which manifest very quickly. Receivers do not have to see the full range of a signaller's signals in order to start gaining familiarity benefits. Reproductive asynchrony and increasing the number of females both enhance learning advantages. We provide theoretical evidence for a strong advantage to specific learning of a signaller's range of signals in signalling systems. Our results have broad implications, not only for understanding communication, but in elucidating additional fitness benefits to group-living, the evolution of individual recognition, and other characteristics of animal behavioural biology.

Rethomics: an R framework to analyse high-throughput behavioural data

The recent development of automatised methods to score various behaviours on a large number of animals provides biologists with an unprecedented set of tools to decipher these complex phenotypes. Analysing such data comes with several challenges that are largely shared across acquisition platform and paradigms. Here, we present rethomics, a set of R packages that unifies the analysis of behavioural datasets in an efficient and flexible manner. rethomics offers a computational solution to storing, manipulating and visualising large amounts of behavioural data. We propose it as a tool to bridge the gap between behavioural biology and data sciences, thus connecting computational and behavioural scientists. rethomics comes with a extensive documentation as well as a set of both practical and theoretical tutorials (available at https://rethomics.github.io).