Through the looking glass: how do marked dolphins use mirrors and what does it mean?

Funding: Studienstiftung des Deutschen Volkes; Deutsche Forschungsgemeinschaft (Gu227/16-1).Mirror-guided self-inspection is seen as a cognitive hallmark purportedly indicating the existence of self-recognition. Only a few species of great apes have been reported to pass a standard mark test for mirror self-recognition in which animals attempt to touch a mark. In addition, evidence for passing the mark test was also reported for Asian elephants, two species of corvids, and a species of cleaner fish. Mirror self-recognition has also been claimed for bottlenose dolphins, using exposure of marked areas to a mirror as evidence. However, what counts as self-directed behaviour to see the mark and what does not has been debated. To avoid this problem, we marked the areas around both eyes of the animals at the same time, one with visible and the other with transparent dye to control for haptic cues. This allowed the animal to see the mark easily and us to investigate what side was exposed to the mirror as an indicator for mark observation. We found that the animals actively chose to inspect their visibly marked side while they did not show an increased interest in a marked conspecific in the pool. These results demonstrate that dolphins use the mirror to inspect their marks and, therefore, likely recognise a distinction between self and others.Publisher PDFPeer reviewe

Acoustic estimation of the manatee population and classification of call categories using artificial intelligence

The population sizes of manatees in many regions remain largely unknown, primarily due to the challenging nature of conducting visual counts in turbid and inaccessible aquatic environments. Passive acoustic monitoring has shown promise for monitoring manatees in the wild. In this study, we present an innovative approach that leverages a convolutional neural network (CNN) for the detection, isolation and classification of manatee vocalizations from long-term audio recordings. To improve the effectiveness of manatee call detection and classification, the CNN works in two phases. First, a long-term audio recording is divided into smaller windows of 0.5 seconds and a binary decision is made as to whether or not it contains a manatee call. Subsequently, these vocalizations are classified into distinct vocal classes (4 categories), allowing for the separation and analysis of signature calls (squeaks). Signature calls are further subjected to clustering techniques to distinguish the recorded individuals and estimate the population size. The CNN was trained and validated using audio recordings from three different zoological facilities with varying numbers of manatees. Three different clustering methods (community detection with two different classifiers and HDBSCAN) were tested for their suitability. The results demonstrate the ability of the CNN to accurately detect manatee vocalizations and effectively classify the different call categories. In addition, our study demonstrates the feasibility of reliable population size estimation using HDBSCAN as clustering method. The integration of CNN and clustering methods offers a promising way to assess manatee populations in visually challenging and inaccessible regions using autonomous acoustic recording devices. In addition, the ability to differentiate between call categories will allow for ongoing monitoring of important information such as stress, arousal, and calf presence, which will aid in the conservation and management of manatees in critical habitats

PolarBearVidID: A Video-Based Re-Identification Benchmark Dataset for Polar Bears

Simple Summary Zoos use automated systems to study animal behavior. These systems need to be able to identify animals from different cameras. This can be challenging, as individuals of the same species might look very alike. AI is the best way to automatically perform this task, especially when using videos instead of images because they show the animal’s movement as additional information. To train the AI model, one needs to have data. This study introduces a new dataset called PolarBearVidID that includes video sequences of 13 polar bears in various poses and lighting conditions. Our AI model is able to identify them with 96.6% accuracy. This shows that using the animals’ movements can help identify them. Abstract Automated monitoring systems have become increasingly important for zoological institutions in the study of their animals’ behavior. One crucial processing step for such a system is the re-identification of individuals when using multiple cameras. Deep learning approaches have become the standard methodology for this task. Especially video-based methods promise to achieve a good performance in re-identification, as they can leverage the movement of an animal as an additional feature. This is especially important for applications in zoos, where one has to overcome specific challenges such as changing lighting conditions, occlusions or low image resolutions. However, large amounts of labeled data are needed to train such a deep learning model. We provide an extensively annotated dataset including 13 individual polar bears shown in 1431 sequences, which is an equivalent of 138,363 images. PolarBearVidID is the first video-based re-identification dataset for a non-human species to date. Unlike typical human benchmark re-identification datasets, the polar bears were filmed in a range of unconstrained poses and lighting conditions. Additionally, a video-based re-identification approach is trained and tested on this dataset. The results show that the animals can be identified with a rank-1 accuracy of 96.6%. We thereby show that the movement of individual animals is a characteristic feature and it can be utilized for re-identification

Feather Corticosterone Measurements and Behavioral Observations in the Great White Pelican (Pelecanus onocrotalus) Living under Different Flight Restraint Conditions in German Zoos

The welfare of zoo birds kept under flight restraint is a frequently discussed topic. Therefore, this study was conducted with one of the most regularly kept types of deflighted birds in German zoos, the great white pelican, to find scientific data regarding welfare assessments of deflighted birds. The detection of corticosterone in feathers (CORTf) as a stress indicator for birds is an almost completely noninvasive form of measurement meant to evaluate the effects of deflighting birds in zoos. Three groups of animals were compared: irreversibly deflighted pelicans that were pinioned or extirpated, reversibly deflighted individuals that were feather-clipped, and airworthy pelicans that were able to fly. Combining two independent research methods, behavioral observation and the measurement of CORTf levels of great white pelicans, we aimed to obtain an objective overview of whether deflighted birds showed differences in CORTf or behavior compared to airworthy birds. As a result of the analysis, we found no significant differences in CORTf between flight-restricted and airworthy birds. However, reversibly deflighted pelicans had higher CORTf values than irreversibly deflighted and airworthy pelicans. In addition, pelicans living in groups consisting of more than 10 individuals showed lower CORTf values than pelicans in groups of less than 10 individuals. "Fluttering" behavior was significantly associated with higher CORTf values. In conclusion, the flight restriction of great white pelicans does not seem to impact the welfare indicators assessed in this study, adrenal activity, or behavior. The data show that the living conditions of pelicans (such as group size) may influence the welfare of these birds. To confirm this, further studies on other ground- and water-based birds are needed to provide more scientific data on animal welfare and living conditions in zoos. The pinioning of birds was previously one of the most-accepted forms of mutilation in zoos. Despite a lack of knowledge on the effects of deflighting procedures with regard to the well-being of deflighted birds, pelicans are often reversibly deflighted by feather-clipping to keep them in open enclosures, including those with ponds without netting. In the present study, we focused on the welfare implications of flight restraint on one of the most commonly kept types of birds in German zoos, the great white pelican. A combination of behavioral observations and feather corticosterone concentrations (CORTf) of pelicans with different deflighting statuses (i.e., irreversibly deflighted, reversibly deflighted, and airworthy) was used to evaluate the effects of deflighting status on pelican welfare. We observed 215 individuals in 21 different German zoos. The pelicans lived in differently designed exhibits. An ethogram for these species was developed and their behavior was evaluated by scan sampling. Feather samples from 182 individuals were collected to determine if different deflighting conditions influenced the CORTf and therefore stress levels. The hypothesis was that the CORTf values of airworthy pelicans differ from those of deflighted pelicans. Tendencies with regard to the flight status groups were found. Conversely, reversibly deflighted pelicans had higher CORTf levels than irreversible deflighted and airworthy pelicans. Tendencies with regard to CORTf values and the group size of the kept pelicans were observed. The CORTf values were lower in groups consisting of more than 10 animals. In addition, the frequency of fluttering behavior was positively associated with CORTf values. Pelicans that frequently showed fluttering had higher CORTf values. Therefore, fluttering behavior might be considered a sign of stress levels in pelicans. This study is one of the first important steps in assessing the impact of deflighting procedures on the welfare of great white pelicans kept in zoos

Validation of an Alternative Feather Sampling Method to Measure Corticosterone

The most common feather sampling method for feather corticosterone measurement is by plucking the feathers from the bird’s skin. This procedure performed on living, restrained birds is qualified as an animal experiment according to German/European legislation, which has to be applied for from the competent authorities. The Directive 2010/63/EU requires the full implementation of the 3-R Principle of Russel and Burch in animal experiments, which means not only to replace the use of animals, but also to reduce the number of animals used and to refine procedures whenever possible. In response to this issue, the aim of this study was to validate an alternative, less invasive sampling method by cutting feathers close to the skin in comparison to the gold standard of plucking them. For this proof-of-principle study, a conventional poultry husbandry with trial groups of geese (Anser anser domesticus) and ducks (Anas sterilis) was selected. All birds were kept under the same living conditions to standardize the influencing factors regarding husbandry, and thus, their stress levels. Feather samples were collected between the shoulders from 46 geese and 51 ducks, both by cutting as well as by plucking, directly after slaughter for meat production. Feather corticosterone levels were measured with Enzyme-Linked Immunosorbent Assay (ELISA). Results were compared using Bland–Altman plots and concordance correlation coefficients (CCC). It could be seen that concordance between corticosterone levels in cut and plucked feathers was rather poor: 0.38 for Anser, and 0.57 for Anas. However, comparing the mean corticosterone values in pg/mm of each species with their respective standard deviations, the differences between the methods were negligible. As the results showed that the differences between the individuals were markedly greater than the differences between the methods, the determination of corticosterone levels in cut feathers is valid compared to using plucked feathers. The validation tests of ELISA showed only acceptable repeatability and reliability. Hence, the results should be verified in further studies. In conclusion, it is recommended for future research to use cut instead of plucked feathers for corticosterone measurement

Feather corticosterone measurements of greater flamingos living under different forms of flight restraint

This research was supported by the German Association of Zoological Gardens (Verband der Zoologischen Gärten e.V, VdZ) with 20,000 €.Deflighting zoo birds is a practice that receives increasing criticism due to its presumed incompatibility with animal welfare. To our knowledge, this is the first approach to address this problem in a scientific way. To do this, we compared feather corticosterone (CORTf) from Greater Flamingos (Phoenicopterus roseus, n = 151) of different flight status (i.e., pinioned, feather clipped, airworthy) from twelve different zoological institutions. To complement the hormone measurements, behavioral observations (scan samplings) were conducted prior to feather sampling within the presumed time frame of feather growth. We hypothesized that CORTf of the deflighted flamingos would differ from CORTf of their airworthy conspecifics. No significant difference in CORTf was found between the three groups, and our hypothesis was rejected. However, the impact of the institution itself (i.e., the housing conditions) proved to be the most dominant variable (variance between the institutions = 53.82%). Due to high variability, the behavioral observations were evaluated descriptively but did not give rise to doubt the findings in CORTf. Therefore, we assume that the method of flight restraint of Greater Flamingos does not have a measurable effect on CORTf. We consider this model for evaluating animal welfare of zoo birds a useful tool and provide ideas for further adjustments for consecutive studies

Intra-specific variation in the social behaviour of Barbary macaques (Macaca sylvanus)

Non-human primates show an impressive behavioural diversity, both across and within species. However, the factors explaining intra-specific behavioural variation across groups and individuals are yet understudied. Here, we aimed to assess how group size and living conditions (i.e. captive, semi-free-ranging, wild) are linked to behavioural variation in 5 groups of Barbary macaques (N=137 individuals). In each group, we collected observational data on the time individuals spent in social interactions and on the group dominance style, along with experimental data on social tolerance over food and neophobia. Our results showed that differences in group size predicted differences in the time spent in social interactions, with smaller groups spending a higher proportion of time in close spatial proximity, but a lower proportion of time grooming. Moreover, group size predicted variation in dominance style, with smaller groups being more despotic. Social tolerance was affected by both group size and living conditions, being higher in smaller groups and in groups living in less natural conditions. Finally, individual characteristics also explained variation in social tolerance and neophobia, with socially integrated individuals having higher access to food sources, and higher-ranking ones being more neophobic. Overall, our results support the view that intra-specific variation is a crucial aspect in primate social behaviour, and call for more comparative studies to better understand the sources of within-species variation

El benestar de les aus amb vol restringit

El benestar de les aus de zoològic amb el vol restringit ha estat objecte d'un estudi realitzat per investigadors de la UAB i de la Universitat de Freie en pelicans de diversos recintes d'Alemanya. Els científics han avaluat el benestar d'aquestes aus a través de l'estudi del seu comportament i dels nivells de l'hormona de l'estrès corticosterona. Els resultats mostren que la restricció de vol no influeix en els criteris de benestar avaluats, tot i que sí que ho fan les condicions de l'entorn. Per confirmar-los, però, calen més dades científiques sobre l'impacte en el benestar d'altres espècies d'aus.El bienestar de las aves de zoológico con el vuelo restringido ha sido objeto de un estudio realizado por investigadores de la UAB y la Universidad de Freie en pelícanos de diversos recintos de Alemania. Los científicos han evaluado el bienestar de estas aves a través del estudio de su comportamiento y de los niveles de la hormona del estrés corticosterona. Los resultados muestran que la restricción de vuelo no influye en los criterios de bienestar avaluados, aunque sí que lo hacen las condiciones del entorno. Para confirmarlos, no obstante, son necesarios más datos científicos sobre otras especies de aves.The welfare of zoo birds kept under flight restraint has been studied by researchers of the UAB and the University of Freie with great white pelicans from German zoos. The scientists have evaluated the well-being of the animals through the ethological study and the levels of stress hormone corticosterone. The results show that the flight restriction does not influence the assessed welfare criteria, although the environmental conditions do. To confirm this, further studies are needed to provide more scientific data on other bird animals in captivity

Dolphin-WET—Development of a Welfare Evaluation Tool for Bottlenose Dolphins (Tursiops truncatus) under Human Care

Ensuring high standards of animal welfare is not only an ethical duty for zoos and aquariums, but it is also essential to achieve their conservation, education, and research goals. While for some species, animal welfare assessment frameworks are already in place, little has been done for marine animals under human care. Responding to this demand, the welfare committee of the European Association for Aquatic Mammals (EAAM) set up a group of experts on welfare science, cetacean biology, and zoo animal medicine across Europe. Their objective was to develop a comprehensive tool to evaluate the welfare of bottlenose dolphins (Tursiops truncatus), named Dolphin-WET. The tool encompasses 49 indicators that were either validated through peer review or management-based expertise. The first of its kind, the Dolphin-WET is a species-specific welfare assessment tool that provides a holistic approach to evaluating dolphin welfare. Inspired by Mellor’s Five Domains Model and the Welfare Quality®, its hierarchical structure allows for detailed assessments from overall welfare down to specific indicators. Through combining 37 animal-based and 12 resource-based indicators that are evaluated based on a two- or three-level scoring, the protocol offers a detailed evaluation of individual dolphins. This approach allows for regular internal monitoring and targeted welfare management, enabling caretakers to address specific welfare concerns effectively

Moderne Zoos und die Bedeutung des Tier-Mensch-Kontaktes

Seit Beginn der Menschheitsgeschichte bestand eine sehr enge Beziehung zwischen Mensch und Tier. Diese war jedoch stets von unterschiedlichen Bedürfnissen geprägt. Demnach ist im Laufe der Geschichte ein Wandel der gesellschaftlichen Stellung sowie der Nutzung des Tieres seitens der Menschen zu beobachten. Wurde in den Anfängen das Tier von den Menschen nur als Nahrungs- oder Gefahrenquelle gesehen oder getrieben vom Instinkt der Überlegenheit gar missbraucht, so entwickelte sich über Tausende von Jahren eine Beziehung, die schlussendlich für den Menschen aus dem Tier einen Begleiter, Freund und Helfer entstehen ließ. [...] Die Rolle der Zoos wird erst verständlich, wenn man bedenkt, dass die Hälfte der Weltbevölkerung in Städten lebt und dort keine wirkliche Beziehung zu wilden Tieren und Pflanzen aufgebaut werden kann. [...] Menschen kommen aber nicht nur in den Zoo, um etwas zu lernen, sondern vielmehr weil ihnen Tiere gut tun. Hiermit wird die psychohygienische Funktion des Zoos angesprochen. Der Kontakt zu Tieren ist als ein menschliches Bedürfnis zu verstehen und es ist sicherlich nicht einfach, die Ursache dieses Phänomens wissenschaftlich zu erklären. (DIPF/Orig.