Nonhuman Research Articles

Dogs understand the role of a human partner in a cooperative task

Humans are exceptionally flexible in cooperation, partly due to our ability to recognize the roles of cooperative partners. While some non-human animals understand the need for a partner in such interactions, it is unclear whether they grasp the consequences of their partner’s actions and adjust accordingly. Previous studies utilizing economic games with non-human animals yielded mixed results. We investigated dogs, known for their close cooperation with humans, in a stag hunt game. Dogs could cooperate for better rewards or defect for lower ones, while their human partners would either cooperate, never cooperate, or act randomly. We control for attraction to food, side bias, and local enhancement. Dogs were more likely to coordinate with their partners when it led to better rewards, suggesting that they understood their partner’s actions. By highlighting this cognitive skill in dogs, we advance our knowledge of the intricate mechanisms driving cooperative behavior in non-human animals.

Exploring the prospects, advancements, and challenges of in vitro modeling of the heart-brain axis

Research on bidirectional communication between the heart and brain has often relied on studies involving nonhuman animals. Dependance on animal models offer limited applicability to humans and a lack of high-throughput screening. Recently, the field of 3D cell biology, specifically organoid technology, has rapidly emerged as a valuable tool for studying interactions across organ systems, i.e., gut-brain axis. The initial success of organoid models indicates the usefulness of 3D cultures for elucidating the intricate interactivity of the autonomic nervous system and overall health. This perspective aims to explore the potential of advancing in vitro modeling of the heart-brain axis by discussing the benefits, applications, and adaptability of organoid technologies. We closely examine the current state of brain organoids in conjunction with the advancements of cardiac organoids. Moreover, we explore the use of combined organoid systems to investigate pathophysiology and provide a platform for treatment discovery. Finally, we address the challenges that accompany the use of 3D models for studying the heart-brain axis with an emphasis on generating tailored engineering strategies for further refinement of dynamic organ system modeling in vitro.

Active self-treatment of a facial wound with a biologically active plant by a male Sumatran orangutan

Although self-medication in non-human animals is often difficult to document systematically due to the difficulty of predicting its occurrence, there is widespread evidence of such behaviors as whole leaf swallowing, bitter pith chewing, and fur rubbing in African great apes, orangutans, white handed gibbons, and several other species of monkeys in Africa, Central and South America and Madagascar. To the best of our knowledge, there is only one report of active wound treatment in non-human animals, namely in chimpanzees. We observed a male Sumatran orangutan (Pongo abelii) who sustained a facial wound. Three days after the injury he selectively ripped off leaves of a liana with the common name Akar Kuning (Fibraurea tinctoria), chewed on them, and then repeatedly applied the resulting juice onto the facial wound. As a last step, he fully covered the wound with the chewed leaves. Found in tropical forests of Southeast Asia, this and related liana species are known for their analgesic, antipyretic, and diuretic effects and are used in traditional medicine to treat various diseases, such as dysentery, diabetes, and malaria. Previous analyses of plant chemical compounds show the presence of furanoditerpenoids and protoberberine alkaloids, which are known to have antibacterial, anti-inflammatory, anti-fungal, antioxidant, and other biological activities of relevance to wound healing. This possibly innovative behavior presents the first systematically documented case of active wound treatment with a plant species know to contain biologically active substances by a wild animal and provides new insights into the origins of human wound care.

Unconscious prioritization for face-to-face people.

One central question in the scientific and philosophical study of consciousness is regarding the scope of human consciousness. There is a lively debate as to whether high-level information integration is necessarily dependent on consciousness. This study presents a new form of unconscious integration based on the facingness between two individuals. Using a breaking continuous flash suppression paradigm, Experiments 1-3 found that two facing human heads got a privilege in breaking into awareness compared to nonfacing pairs. Experiments 4 and 5 demonstrated that the breakthrough difference between facing and nonfacing pairs could not be attributed to low-level or mid-level factors. Experiments 6, 7a, and 7b showed that the unconscious priority of facing pairs was significantly diminished when the holistic processing of the two agents was disrupted. Experiments 8-11 demonstrated that the advantage of facing pairs was only observable for human agents and not for daily objects, directional arrows, or nonhuman animals. These findings have critical implications for better understanding the scope of human consciousness and the origins of social vision. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Sense and Symbolic Sensibility: The Rise of Amphibians and the Roots of Language in Whiteheadian Perspective

Abstract Perspectives on the difficult topic of the evolution of language can be differentiated to a large extent based on how much relevant continuity or discontinuity they see between humans and nonhuman animals. In general, biologists and psychologists tend to have a broad definition of “language” that highlights significant continuities, whereas linguists tend to define “language” more narrowly, in accord with their emphasis on the uniqueness of human capacities. This article examines the value of Whitehead's innovative theory of language, which is grounded in his account of the fundamental symbolic element in basic perceptual processes, mainly for understanding the continuities between animal and human perceptual and symbolic activity but also for accommodating the discontinuity, or at least the pivotal difference, evident in the full flowering of human language. It will focus particularly on applying Whitehead's approach to gain a new understanding of the emergence, with the rise of amphibians, of the first vocalization in the history of life.

Singular thought without temporal representation?

What is required for an individual to entertain a singular thought about an object they have encountered before but that is currently no longer within their perceptual range? More specifically, does the individual have to think about the object as having been encountered in the past? I consider this question against the background of the assumption that non-human animals are cognitively ‘stuck in the present’. Does this mean that, for them, ‘out of sight is out of mind’, as, e.g., Schopenhauer seems to have thought? I suggest an alternative answer, also drawing on some empirical work on animal cognition.

Between social cognition and material engagement: the cooperative body hypothesis

AbstractIn recent years, social cognition approaches to human evolution and Material Engagement Theory have offered new theoretical resources to advance our understanding of the prehistoric hominin mind. To date, however, these two approaches have developed largely in isolation from one another. I argue that there is a gap between social- and material-centred approaches, and that this is precisely the sociomateriality of the appearance of ancestral hominin bodies, which evolved under selective pressure to develop increasingly complex, cooperative sociality. To get this sociomaterial body in focus, I develop an esthesiological framework, appropriated from Merleau-Ponty (2003), for interpreting the expressive body in an evolutionary and comparative context. The guiding hypothesis of esthesiology is that before being rationality (social or material), “humanity is another corporeity” (Merleau-Ponty, 2003, p. 208). Esthesiology studies the appearance of the body and its sense organs as an intertwining locus of a sensing power (the ability to see, to touch, etc.) and a sensible character (the visible, touchable body). It is this dual-aspect character of the body that facilitates the most basic affective and sensorimotor modes of sociality. Examining these features from a comparative perspective, we find that the human body is distinctively suited to prosocial communication and cooperation: a more cooperative eye, an exposed and communicative skin. I thus propose a cooperative body hypothesis, by analogy with the cooperative eye hypothesis (Tomasello et al., 2007). Esthesiology provides a framework for integrating and interpreting a wide range of otherwise disconnected facts concerning human and nonhuman animal bodies, forms of life, cognition, and evolution, thereby bridging the gap between social cognition and material engagement perspectives. In doing so, however, it not only solves problems and proposes new directions of investigation, but also demands theoretical revisions from each.

The macroecology of butyrate-producing bacteria via metagenomic assessment of butyrate production capacity.

Butyrate-producing bacteria are found in many outdoor ecosystems and host organisms, including humans, and are vital to ecosystem functionality and human health. These bacteria ferment organic matter, producing the short-chain fatty acid butyrate. However, the macroecological influences on their biogeographical distribution remain poorly resolved. Here we aimed to characterise their global distribution together with key explanatory climatic, geographical and physicochemical variables. We developed new normalised butyrate production capacity (BPC) indices derived from global metagenomic (n = 13,078) and Australia-wide soil 16S rRNA (n = 1331) data, using Geographic Information System (GIS) and modelling techniques to detail their ecological and biogeographical associations. The highest median BPC scores were found in anoxic and fermentative environments, including the human (BPC = 2.99) and non-human animal gut (BPC = 2.91), and in some plant-soil systems (BPC = 2.33). Within plant-soil systems, roots (BPC = 2.50) and rhizospheres (BPC = 2.34) had the highest median BPC scores. Among soil samples, geographical and climatic variables had the strongest overall effects on BPC scores (variable importance score range = 0.30-0.03), with human population density also making a notable contribution (variable importance score = 0.20). Higher BPC scores were in soils from seasonally productive sandy rangelands, temperate rural residential areas and sites with moderate-to-high soil iron concentrations. Abundances of butyrate-producing bacteria in outdoor soils followed complex ecological patterns influenced by geography, climate, soil chemistry and hydrological fluctuations. These new macroecological insights further our understanding of the ecological patterns of outdoor butyrate-producing bacteria, with implications for emerging microbially focused ecological and human health policies.

Molecular epidemiology and multilocus genotyping of Giardia duodenalis in individuals attending major public hospitals in Shiraz, southwestern Iran: A public health concern

Giardia duodenalis is one of the most common causes of waterborne disease worldwide, and is often associated with outbreaks of diarrhea in areas with poor sanitation and hygiene. This study aimed to assess the prevalence and genetic diversity of G. duodenalis assemblages in individuals attending major public hospitals in Shiraz, southwestern Iran. From August 2022 to May 2023, a total of 614 stool samples from individuals were collected and initially examined for G. duodenalis cysts using parasitological techniques, sucrose flotation, and microscopy. Microscopy-positive samples were validated by SSU-PCR amplification of the parasite DNA. A multilocus genotyping (MLG) scheme, which focused on the triose phosphate isomerase (tpi) and the glutamate dehydrogenase (gdh) genes, was employed for genotyping purposes. G. duodenalis cysts were found in 7.5% (46/614) and 8.5% (52/614) of samples through microscopy and SSU-PCR, respectively. Successful amplification and sequencing results were obtained for 77.3% (17/22) and 45.5% (10/22) of the infected samples at the tpi and gdh loci, respectively. MLG data for the two loci were available for only five samples. Out of the 22 samples genotyped at any loci, 54.5% (12/22) were identified as assemblage A, while 45.5% (10/22) were identified as assemblage B. AII was the most predominant sub-assemblage identified [54.5% (12/22)], followed by BIII [27% (6/22)], discordant BIII/BIV [13.6% (3/22)], and BIV [4.5% (1/22)]. In the present study, no assemblages suited for non-human animal hosts (e.g., CF) were detected. This suggests that the transmission of human giardiasis in Shiraz is primarily anthroponotic. Further molecular-based analyses are necessary to confirm and expand upon these findings. These analyses will also help determine the presence and public health importance of the parasite in environmental samples, such as drinking water.

Human decomposition in the unique context of the Andaman and Nicobar Islands (India): a comparative analysis with reference data

ABSTRACT The understanding of the victim’s decomposition process is crucial in forensic science for establishing accurate time since death, and the overall timelines of criminal investigations. Global research, which primarily relies on non-human animal proxies, highlights a scarcity of facilities using human bodies and a lack of baseline data for some regions and remote locations. In cases such as the Andaman and Nicobar (A&N) Islands (India), forensic practitioners turn to literature-derived patterns developed at the closest locations (mostly mainland India). This study examines 51 human decomposition cases investigated in A&N in comparison with the existing literature, emphasizing distinctions and similarities in their decomposition relative to the current Indian literature. This study advocates for further research and potentially calls for the establishment of the first anthropology research facility in the Indo-Pacific region, encouraging the development of tailored methodologies for more accurate estimations in diverse environments.

Measuring heart rate in captive chimpanzees without anesthesia.

Heart rate measurements can be useful for the monitoring of both physical and mental condition in humans and nonhuman animals. Yet, information about heart rates in chimpanzees, who are phylogenetically the closest species to humans, is scarce. Existing data on chimpanzee heart rates have mainly been collected from chimpanzees under anesthesia. To address this issue, we conducted electrocardiogram recordings in captive chimpanzees under normal conditions without anesthesia based on positive reinforcement training. We obtained a total of 771 recordings from 35 individuals (22 males and 13 females, 14-53years old) with no cardiac problems. The females had a higher heart rate than the male chimpanzees, and heart rate decreased as a function of age. In addition, heart rate was lower in the morning and increased during the day. Overall, the mean heart rate of adult males was 86.5 beats/min, and that of female chimpanzees 106.4 beats/min. Our data could serve as a reference point for future research and health-based monitoring of chimpanzee heart rates.

Weighing the moral status of brain organoids and research animals.

Recent advances in human brain organoid systems have raised serious worries about the possibility that these in vitro 'mini-brains' could develop sentience, and thus, moral status. This article considers the relative moral status of sentient human brain organoids and research animals, examining whether we have moral reasons to prefer using one over the other. It argues that, contrary to common intuitions, the wellbeing of sentient human brain organoids should not be granted greater moral consideration than the wellbeing of nonhuman research animals. It does so not by denying that typical humans have higher moral status than animals, but instead by arguing that none of the leading justifications for granting humans higher moral status than nonhuman animals apply to brain organoids. Additionally, it argues that there are no good reasons to be more concerned about the well-being of human brain organoids compared to those generated from other species.

The forgotten adaptive social benefits of social learning in animals.

Theoretical and empirical scholars of cultural evolution have traditionally studied social learning strategies, such as conformity, as adaptive strategies to obtain accurate information about the environment, whereas within social psychology there has been a greater focus upon the social consequences of such strategies. Although these two approaches are often used in concert when studying human social learning, we believe the potential social benefits of conformity, and of social learning more broadly, have been overlooked in studies of non-humans. We review evidence from studies of homophily, imitation, and rapid facial mimicry that suggests that behaving like others affords social benefits to non-human animals and that behaviour matching may be deployed strategically to increase affiliation. Furthermore, we review studies of conformity in dispersers, and suggest that forgoing personal information or preferences in favour of those of the new group during immigration may be a strategy to facilitate social integration. We therefore propose that the informational and social functions of conformity apply to humans and animals alike. We use this perspective to generate several interesting research questions to inspire work in this field. For example, under what conditions do animals use informational or social conformity and what role does uncertainty play in social learning in immigrant individuals?

Walking with sheep, dancing with dragonflies: moving-with multispecies ecologies

ABSTRACT Based on the authors’ fieldwork with sheep and dragonflies, this article explores multispecies methods as moving-with multispecies ecologies. Apart from being scholars, both authors are performance practitioners engaging with more-than-human environments. As a part of an art exhibition in 2015, Charlotte did a performative walk with a sheep for 5 weeks, intra-acting with the sheep and the other human and non-human animals inhabiting the heath, the weather conditions, the local visitors and media. Linda has been dancing by Utterslev marsh, a nature-culture area in Copenhagen, since 2020, exploring mo(ve)ments of connection with multiple bodies in the surroundings, including dragonflies. Performing multispecies research as a practice of relationality, the article takes shape as a conversation, evolving around three themes: moving-with multispecies ecologies; pace, speed/slowness and letting go; and entangled ethics and vulnerabilities. ‘Moving-with’ invites qualitative researchers to explore movement, speed and temporality in the entangled multispecies ecologies they become a part of.

Un singe compatissant

<p>Through a cross-reading of the fictional epistle Lettre d’un singe aux êtres de son espèce, and the utopia La Découverte australe par un homme volant, this article aims to highlight the originality of the conception of animality expressed by the polygraph Nicolas-Edme Restif de La Bretonne (1734-1806). Indeed, Restif is able in these writings, thanks to an imaginative representation of animality, to go beyond the simple criticism of anthropocentrism, to insert animal literature at the centre of the process of ‘invention’ of the rights of man and woman typical of the Enlightenment. Restif’s pamphlet is indeed focused – from a philosophical point of view – on the imaginative and projective dimension of compassion, mobilised by fiction, which allows the subject to go beyond his usual picture of life, until authentically sympathising with all possible forms of otherness, embodied by the non-human animal – the monkey – and by the half-breed, i.e. the man-beast.</p>

L’animal non humain comme élément constitutif de différents topoï narratifs dans la littérature européenne

<p>The growing interest in non-human animals is driven by advancements in biotechnology and an increased awareness of the importance of preserving biodiversity. This fascination with non-human creatures dates back far in history. Exploring the representation and interpretation of the animal world throughout different epochs helps us better understand our relationship with other forms of life and appreciate the richness of works celebrating the animal kingdom. Animal motifs, laden with symbolic meanings, provide a complex field of study where recurring patterns are less evident. This volume explores these relevant recurrences and identifies the narrative patterns that shape these animal representations, enabling a deeper understanding of the relationship between humans and animals.</p>

The Great Web of Being: Environmental Ethics without Value Hierarchy

Hierarchical views of the world such as the great chain of being have come under sustained critique in recent decades, and rightly so. They have justified not only the domination of non-human creatures but also the devaluation (via animalization/racialization) of many humans. The rejection of hierarchy and the great chain of being, however, does not require the rejection of the Christian Platonic theological vision upon which hierarchy is often based. In this paper, I argue that Christian Platonic theology has always been in tension with the great chain of being and is better suited to a non-hierarchical view of creaturely value. I then develop the ethical implications of this view in dialogue with both environmental and animal ethics and anti-racist and decolonial scholarship.

More than a simple fixed action pattern: Yawning in drills.

In the last decade, increasing attention has been devoted to exploring some aspects of yawning in non-human animals. With their chin red mark, bony paranasal swellings, male large brains and long canines, drills (Mandrillus leucophaeus) offer a robust model for testing hypotheses on the phenomenon. We identified two yawn variants (covered, YCT and uncovered teeth, YUCT) which differ in terms of recruitment of muscular action units (AUs). We tested the effects of several variables (sex, dominance rank, context) on the duration of the yawn and the probability of YCT or YUCT occurrence. We found that males performed longer and more YUCT than females. These findings support the Brain Cooling Hypothesis suggesting that those species showing large brains tend to display larger and longer yawns. We also tested the State Changing Hypothesis predicting the presence of a temporal association of yawning and ongoing behavioral transitions. A sequential analysis revealed that after 30s following a yawn, drills were significantly more likely to change their behavioral state. Through the observation of yawning, conspecifics might gain knowledge of impending state changes. Seeing other's yawns increased the probability of a similar response in the observers, thus suggesting the presence of yawn contagion in drills. Although the dataset needs to be expanded, our findings indicate that yawning is variable in drills, it can be associated with subjects' state changes, and the imminent shifts can be perceived/processed by conspecifics.

Fenced Europe: A more-than-human perspective to border control. The case of Białowieża

Abstract Belarus willingly uses migrants as a tool for political pressure, sending them into forests bordering the EU. This prompted Poland to secure its territory with additional troops and, first, to build a razor wire fence, and, second, to build an entire wall made of steel and concrete. The humanitarian situation of migrants stuck in the Białowieża forest has been dire. An underexposed theme is how not only people were hurt by the border policies, but non-human animals were also affected. As the effects of fencing ‘fortress Europe’ on wildlife are widespread (spatial behaviour, movements and gene flow), this paper uses the Polish–Belarusian border as a case study of a conflict between human border policies and non-human interests. We argue that the plans for the Polish wall are illegal, politically unjust and unethical, also from a more-than-human perspective. The wall is illegal because requirements under EU environmental law, in particular Article 6 of the Habitats Directive, were not met. The wall is unjust because it painfully demonstrates how animals’ communal or even liminal status is far from being recognised. Finally, the wall is unethical because it fails to account for the vulnerability of both humans and non-humans.

The Anvil, the Ascent, and Enoch

First Enoch, a pseudepigraphical work from the Second Temple period, contains visions of the natural and supernatural world that cause the visionary, Enoch, to understand anew the beyond-human world. Written during a time of environmental devastation, 1 Enoch can be a resource for helping today’s readers rewild our religious imaginations, our understanding of worship, and our relationship with nonhuman creation. This essay offers a reflection on how the Book of the Watchers in 1 Enoch and the author’s failed attempts to reach a mountain peak helped the author better understand the unseating of humanity as the center of creation as an experience of grace.