Biology subjects

Carvalho, S.

Publications and source records attributed to Carvalho, S..

At least 19 recordsLinked to original sources

bioRxiv2026

Self-generated oxygen limitation drives coral outcomes during marine heatwaves

Marine heatwaves cause massive, but often patchy coral bleaching. Why neighboring colonies often respond differently remains unresolved. Here, we show that interactions between metabolic demand and flow-mediated resupply generate heterogeneous oxygen microenvironments inside branching corals under heat stress. During the 2023 and 2024 Red Sea heatwaves, high-frequency in situ measurements revealed hypoxic to near-anoxic interbranch conditions despite well-oxygenated surrounding seawater. In 2023, neighboring colonies developed divergent oxygen regimes preceding paling and bleaching; in 2024, stronger and earlier thermal stress was associated with recurrent nighttime near-anoxia before tissue disintegration and mortality. A physics-based three-dimensional fluid-metabolism model reproduced these patterns. Oxygen depletion and coral impacts emerged when metabolic oxygen demand exceeded flow-mediated resupply. Organism-scale variability in oxygen regimes may explain divergent coral fate under shared heatwave exposure.

ecology↗

bioRxiv2026

Leaf and root microbiome signatures of gray mangrove trees in the Red Sea

Mangroves persist under strong environmental constraints with support from microbes. Although microbial communities differ among mangrove compartments, their assembly mechanisms and compartment-specific functional signatures remain poorly resolved. Here, we combine peptide nucleic acid-clamping coupled with 16S rRNA gene amplicon sequencing and genome-resolved metagenomics to investigate the microbial communities associated with the leaves and roots of gray mangrove trees in the Red Sea. Our results suggest homogeneous selection and homogenizing dispersal as key processes of microbial community assembly in leaves. This phyllosphere hosts novel prokaryotic lineages, with some of its members probably synthesizing rhodopsins, plant polysaccharide-degrading enzymes, and gamma-aminobutyric acid, a metabolite that increase tolerance to salinity stress. Genomes affiliated with Desulfobacterales and Sedimenticolaceae taxa are abundant belowground, suggesting complementary sulfur- and nitrogen-cycling capacities similar as occur in other blue-carbon ecosystems. Comparison with root-derived genomes from cordgrass revealed a host-driven selection of Sedimenticolaceae species with convergent metabolic profiles. Overall, this study provides an integrative view about the microbial biology of gray mangrove trees, offering foundational insights into the diversity, ecology, and predictive functionality of their aboveground-belowground microbiomes.

microbiology↗

bioRxiv2026

Context-Dependent Reactive Antipredator Behavior of Chacma Baboons (Papio ursinus) Amidst Predator Recovery

Predation is a driving force in the ecology and evolution of prey, and primates exhibit diverse anti-predator strategies for minimizing risk. Because these behaviors can be costly, individuals must balance costs and benefits when responding to perceived threats. The cognitive capacity and behavioral plasticity of baboons make them an ideal taxon for studying the context-dependent variation in anti-predator strategies. Here, we used an autonomous, motion-activated playback experiment to study the behavioral responses of chacma baboons (Papio ursinus griseipes) to simulated predator encounters in Gorongosa National Park, Mozambique. We compared responses in 2021, when predator densities were relatively low, to responses in 2024, after predation increased due to lion (Panthera leo) population recovery and African wild dog (Lycaon pictus) reintroduction. We compared flight and vigilance responses to vocalizations of these common predators with responses to leopard (Panthera pardus), historically a key predator; spotted hyena (Crocuta crocuta), a rare predator; and cheetah (Acinonyx jubatus), absent historically and currently. We also assessed how responses varied with habitat, age-sex class, presence of offspring, and group size. Across 916 predator playbacks, baboons fled in 19% and displayed vigilance in 71% of trials. When predator density was higher, baboons displayed weakened antipredator responses, consistent with the risk allocation hypothesis. Baboons were more likely to flee in response to lion and wild dog cues. Juveniles fled more frequently than other demographic classes, while adult females with offspring were more vigilant. Overall, responses were highly heterogeneous, reflecting the substantial intraspecific variation and behavioral flexibility characteristic of baboons.

animal behavior and cognition↗

bioRxiv2026

Coral Probiotics Buffer Adjacent Ecosystem-Level Responses to Extreme Marine Heatwave

Probiotics can enhance coral thermal tolerance, yet their ecosystem-level effects remain unknown. Here, we present the first long-term in-situ test of whether coral-targeted probiotics influence adjacent cryptobenthic reef communities during a record marine heatwave. Probiotics were applied to Pocillopora favosa and Acropora spp. coral colonies for 18 months, spanning the fourth global bleaching event. Cryptobenthic communities were assessed using biomimetic monitoring structures integrating biodiversity surveys, molecular profiling, microbial network analyses, and metabolic assays. Before the heatwave, probiotic and control patches were comparable across structural, microbial, and functional metrics. Following thermal stress, control patches exhibited pronounced losses of cryptobenthic invertebrate abundance and taxonomic breadth, microbial network fragmentation, and net carbonate dissolution. In contrast, probiotic-treated patches retained higher biodiversity, cohesive microbial interaction architectures, and positive calcification. These findings demonstrate that coral-targeted probiotics can scale from host-level intervention to buffer adjacent ecosystem-level responses to extreme marine heatwaves under accelerating climate change. TeaserA coral-targeted probiotic strategy enhances multi-trophic resilience under heat stress.

microbiology↗

bioRxiv2026

Environmental DNA reveals hidden eukaryotic diversity and fine-scale community patterns across seascape areas in the Northern Red Sea

Understanding how reef-associated biodiversity responds to seascape features is essential for monitoring and conserving coral reef ecosystems. Environmental DNA (eDNA) from seawater provides access to benthopelagic eukaryotic diversity but its relationship with benthic structure remains poorly understood. We conducted simultaneous assessment of benthopelagic eDNA derived from near-reef seawater and benthic photoquadrat surveys across 12 coral reef sites in the northern Red Sea, spanning three seascape regions: the Gulf of Aqaba, nearshore Northern Red Sea (NRS), and offshore NRS. We examined whether spatial patterns in benthopelagic eDNA communities were structured across regions and whether variation in benthic cover explained differences in eDNA-derived assemblages obtained from water samples. Benthopelagic eDNA revealed fine-scale spatial structuring across regions but showed non-significant whole-community correlation with benthic composition. When examined by major taxonomic groups, taxon-specific relationships emerged, with some taxa (i.e., Micromonas sp.) showing increasing relative abundances in reefs characterized by lower benthic complexity. While traditional photoquadrat surveys captured 72 benthic sessile taxa including dominant benthic groups (e.g. hard corals and algae) across four eukaryotic phyla, benthopelagic eDNA documented a broader range of eukaryotic diversity, including planktonic, cryptic, and low abundant taxa spanning 35 phyla. Notably, eDNA detected cryptic organisms overlooked by visual surveys, such as the giant clam Tridacna sp., even where present but not recorded in photoquadrats. Our results demonstrate that benthopelagic eDNA and visual surveys provide complementary perspectives on reef biodiversity. Rather than serving as a direct proxy for benthic structure, benthopelagic eDNA captures spatial and taxonomic patterns that may be overlooked by visual transects, supporting its use in seascape-scale biodiversity assessments and conservation planning efforts in dynamic and understudied reef systems.

ecology↗

bioRxiv2025

Girdin controls the pace of 3D tracheal cell intercalation by coupling adherens junctions to the actin cytoskeleton in Drosophila

Morphogenesis is orchestrated through coordinated cell movements, including cell intercalation, which drives extensive changes in cell shape and position. This process requires precise regulation of interactions between Adherens Junctions (AJs) and the cortical actin network to generate the necessary mechanical forces. Although the Myosin molecular motor II plays a central role in generating morphogenetic forces, it is dispensable for processes such as dorsal branch (DB) morphogenesis in the Drosophila tracheal system, where coordinated cell migration and three-dimensional intercalation rely on alternative, yet poorly characterised mechanisms of force generation. Here, we show that Vinculin and Ajuba LIM protein, two key regulators of mechano-transduction and cell adhesion, do not localise to AJs of DBs, while the cytoskeletal adaptor Girdin does. We demonstrate that Girdins function relies on AJ components -Catenin and E-Cadherin and is specifically required in tracheal cells to ensure the proper pace of cell intercalation. In addition, Girdin contributes to the actin network enrichment at AJs. Its role as an integral AJ component is further elucidated through the development of a novel genetic tool enabling in vivo cell-specific actin depolymerisation. Summary StatementDrosophila Girdin contributes to the pace of tracheal cell intercalation by linking adherens junctions to actin. A genetic tool for actin depolymerisation reveals Girdin as a key adherens junction component.

developmental biology↗

bioRxiv2025

Specialised super-enhancer networks in stem cells and neurons

Super-enhancers (SEs) are clusters of enhancers with high transcriptional activity that play essential roles in defining cell identity through regulation of nearby genes. SEs preferentially form multiway chromatin interactions with other SEs and highly transcribed regions in embryonic stem cells. However, the properties of the interacting SEs and their specific contributions to complex regulatory interactions in differentiated cell types remain poorly understood. Here, we compare the structural and functional properties of SEs between embryonic stem cells (ESCs) and dopaminergic neurons (DNs) by combining Genome Architecture Mapping (GAM), chromatin accessibility, histone modification, and transcriptome data. Most SEs are cell-type specific and establish extensive pairwise and multiway chromatin interactions with other SEs and genes with cell-type specific expression. SE interactions span megabase genomic distances and frequently connect distant topologically associating domains. By applying network centrality analyses, we detected SEs with different hierarchical importance. Highest network centrality SEs contain binding motifs for cell-type specific transcription factors, and are candidate regulatory hubs. The functional heterogeneity of SEs is also highlighted by their organisation into modular sub-networks that differ in structure and spatial scale between ESCs and DNs, with more specific and strongly connected SE modules in post-mitotic neurons. Our results uncover both the high complexity and specificity of SE-based 3D regulatory networks and provide a resource for prioritizing SEs with potential roles in transcriptional regulation and disease.

genomics↗

bioRxiv2025

Increased RAMP3 expression enhances GLP-1 mediated Glucose Stimulated Insulin Secretion in a Manner Dependent on Ca2+ Mobilisation

The targeting of the Glucagon-like peptide-1 receptor (GLP-1R) for diabetes and obesity is not a novel strategy, with recent therapeutics showing efficacy in weight loss and glycaemic control. However, they are also associated with side effects, including gastrointestinal disruptions and pancreatitis. Developing agonists with different signalling profiles, or that exert some tissue selectivity can circumvent these on-target, unwanted effects. Receptor activity-modifying proteins (RAMPs) offer the potential to do both, through modulation of agonist binding and signalling, as well as surface expression. The GLP-1R was found to interact with RAMP3, with the heterodimer able to bind agonist at the cell surface. RAMP3 expression biased the receptor towards Ca2+ mobilisation, away from the canonical cAMP-driven signalling. When examining G protein coupling, the interaction with RAMP3 reduced activation of the cognate Gs but increased secondary couplings to Gq and Gi. These increased couplings led to an elevation in glucose-stimulated insulin secretion when cells overexpressing RAMP3 were stimulated with GLP-1. A reciprocal effect was observed when looking at reduced expression of endogenous RAMP3, with a loss of sensitivity to GLP-1 in both glucose and insulin tolerance tests in a Ramp3 knockout mouse. The effects of this interaction can then inform selection of models and peptide design when targeting this receptor for therapeutic intervention. Significance StatementG Protein-Coupled Receptors, such as the Glucagon-Like Peptide-1 (GLP-1) Receptor are common drug targets, although not without side effects due to on-target, unwanted signalling outputs. This study identifies an interacting protein which alters its signalling to promote insulin secretion. This may improve the therapeutic potential of GLP-1 mimetics, enhancing effectual signalling over that associated with unwanted effects by directly targeting this receptor complex.

pharmacology and toxicology↗

bioRxiv2024

Old age variably impacts chimpanzee engagement and efficiency in stone tool use

We know vanishingly little about how long-lived apes experience senescence in the wild, particularly with respect to their foraging behaviors, which are essential for survival. Some wild apes use tools during foraging and, given the additional cognitive and physical challenges presented by tool use, we predict that such behaviors are at a heightened risk of senescence. However, until the present, longitudinal analysis of the effects of progressive aging on wild ape tool-use behaviors has not been possible due to a lack of available data. In response to this research gap, we sampled data from a longitudinal video archive that contained footage of wild chimpanzees engaging in one of their most complex forms of tool use - the cracking of hard-shelled nuts with hammers and anvil stones, termed nut cracking - at an outdoor laboratory at Bossou, Guinea. By sampling data over a 17-year period, we describe how the extent to which wild chimpanzees engage in - and efficiently perform - nut cracking changes between the ages of approximately 39-44 to 56-61 years of age. Over this extended sampling period, chimpanzees began attending experimental nut cracking sites less frequently than younger individuals. Several elderly chimpanzees exhibited reductions in efficiency across multiple components of nut cracking, including taking more time to select stone tools prior to use, and taking longer to crack open nuts and consume the associated pieces of kernel. Two chimpanzees also began using less streamlined behavioral sequences to crack nuts, including a greater number of actions (such as more numerous strikes of the hammer stone). Most notably, we report interindividual variability in the extent to which elderly chimpanzees tool-use behaviors changed during our sample period - ranging from small to profound reductions in tool engagement and efficiency - as well as differences in the specific aspects of nut cracking behaviors that changed for each individual as they aged. We discuss the possible causes of these changes with reference to research into senescence in captive primates, and provide future directions for research of primate aging in both captive and wild settings.

animal behavior and cognition↗

bioRxiv2024

Molecular hydrogen can minimize negative effects of heat stress on the hard coral genus Acropora

Coral reefs are increasingly threatened by mass bleaching events due to global ocean warming. Novel management strategies are urgently needed to support coral survival until global efforts can mitigate ocean warming. Given the strong antioxidant, anti-inflammatory and anti-apoptotic properties of molecular hydrogen, our study explores its potential to alleviate the negative effects of heat stress on corals. We investigated the ecophysiological responses of two common hard corals (Acropora spp. and Pocillopora verrucosa) from the Central Red Sea under ambient (26 {degrees}C) and elevated seawater temperatures (32 {degrees}C), with and without hydrogen addition ([~] 150 {micro}M H2) over 48 h. Our results showed that at 32 {degrees}C without hydrogen addition, P. verrucosa exhibited high temperature tolerance, whereas Acropora spp. showed significant reductions in photosynthetic efficiency and maximum electron transport rate compared to the ambient condition (26 {degrees}C). The addition of hydrogen at 32 {degrees}C increased the maximum electron transport rate of Acropora spp. by 28 %, maintaining it at levels compared to those at 26 {degrees} C. This suggests that molecular hydrogen benefits specific coral species under heat stress in the short-term. This study provides the foundation for future long-term and in-situ studies, potentially guiding the development of new management strategies aiming at enhancing coral resilience to ocean warming.

ecology↗

bioRxiv2024

The ontogeny of chimpanzee technological efficiency

Primate extractive foraging requires years of dedicated learning. Throughout this period, learners peer at conspecifics engaging in the behaviour ("models"), interacting with the model and their tools, and sometimes stealing the freshly extracted resource. This also corresponds to an extended period of tolerance from the models. Yet the long-term effect of variation in experiences during this period on the technological efficiency of individuals is unknown for primate tool use, and no research has assessed the role of both the learner and the model(s) in generating individual differences. Using >680 hours of video spanning 25 years, we assessed whether experiences during the stone tool use social learning period ("early learning period"; ages 0-5) predicted the post-early learning period (ages 6+) technological efficiency in wild chimpanzees in Bossou, Guinea. We found that learners varied in how frequently they peered at the models whole nut-cracking bouts, how many learning opportunities their mothers presented, and the amount of tolerance and intolerance they experienced from all selected models. Learners who experienced more intolerance became less efficient tool users, whereas learners who were exposed to more social learning opportunities and tolerance became more efficient. Peering at the whole nut-cracking bout decreased subsequent efficiency, hinting at learners acquiring less efficient cultural components of the behaviour. Our findings highlight the role of social learning in the acquisition of stone tool use and support the view that social learning opportunities within a tolerant environment are key in explaining the emergence and maintenance of complex forms of primate technology. Significance StatementThe capacity and inclination to learn from others, along with social learning opportunities provided by tolerant groupmates, are thought to have enabled the evolution of technology in primates, including hominins. The influence of the learning period on long-term individual variation in technological efficiency remains unknown for non-human primates but has significant implications for cultural transmission and evolution. We provide longitudinal support for the hypothesis that exposure to social learning opportunities during development predicts subsequent technological efficiency. Moreover, we show that low amounts of intolerance, not just general tolerance, is key in the ontogeny of technological efficiency. Finally, we find aspects of behavioural acquisition relating to accurate transmission of cultural traits rather than to learning to use tools efficiently.

animal behavior and cognition↗

bioRxiv2024

Tool skill impacts the archaeological evidence across technological primates

The archaeological record offers insights into our evolutionary past by revealing ancient behaviour through stone and fossil remains. Percussive foraging is suggested to be particularly relevant for the emergence of tool-use in our lineage, yet early hominin percussive behaviours remain largely understudied compared to flaked technology. Stone tool-use of extant primates allows the simultaneous investigation of their artefacts and the associated behaviours. This is important for understanding the development of tool surface modification, and crucial for interpreting damage patterns in the archaeological record. Here, we compare the behaviour and the resulting material record across stone tool-using primates. We investigate the relationship of nut-cracking technique and stone tool modification across chimpanzees, capuchins, and long-tailed macaques by conducting standardized field experiments with comparable raw materials. We show that different techniques likely emerged in response to diverse nut hardness, leading to variation in foraging success across species. Our experiments further demonstrate a correlation between techniques and the intensity of visible percussive damage on the tools. Tools used with more precision and efficiency as demonstrated by macaques, show fewer use wear traces. This suggests that some percussive techniques may be less readily identified in the archaeological record.

animal behavior and cognition↗

bioRxiv2023

SRRM2 splicing factor modulates cell fate in early development

Embryo development is an orchestrated process that relies on tight regulation of gene expression to guide cell differentiation and fate decisions. Alternative splicing is modulated during development as an additional layer of regulation to reprogram gene expression patterns. The Srrm2 splicing factor has recently been implicated in developmental disorders and diseases, but its role in early mammalian development remains unexplored. Here, we show that Srrm2 dosage is critical for maintaining embryonic stem cell pluripotency and cell identity. Srrm2 heterozygosity promotes loss of stemness, characterized by the coexistence of cells expressing naive and formative pluripotency markers, together with extensive changes in gene expression, including genes regulated by serum- response transcription factor and differentiation-related genes. Depletion of Srrm2 by RNA interference in embryonic stem cells shows that the earliest effects of Srrm2 half-dosage are specific alternative splicing events on a small number of genes, followed by expression changes in metabolism and differentiation-related genes. Our findings unveil molecular and cellular roles of Srrm2 in stemness and lineage commitment, shedding light on the roles of splicing regulators in early embryogenesis, developmental diseases and tumorigenesis. Summary statementThis article emphasizes the importance of splicing regulators in early mammalian development by uncovering roles of SRRM2 splicing factor dosage in pluripotency, providing novel insights for a better understanding of Srrm2-related diseases.

developmental biology↗

bioRxiv2023

Stable long-term individual variation in chimpanzee technological efficiency

Using tools to access hard-to-reach and high-quality resources, such as termites, honey, and nuts, initiated a fundamental adaptive shift in human and nonhuman primate cognitive and behavioural evolution. Variation in the efficiency of extracting calorie-rich and nutrient-dense resources directly impacts energy expenditure, and potentially has significant repercussions for cultural transmission where model selection biases are employed during skill acquisition. Assessing variation in efficiency is key to understanding the evolution of complex behavioural traits in primates. Yet, individual-level differences beyond age- and sex-class in primate extractive foraging efficiency have never been investigated. Here, we used 25 years (1992- 2017) of video data of the Bossou chimpanzee community (Guinea), to investigate whether individual differences in nut-cracking efficiency exist across the life span of chimpanzees aged [≥] 6 years. Data from 3,882 oil-palm nut-cracking bouts from over 800 hours of observation were collected. We found long-term stable and reliable individual differences in four (out of five) measures of efficiency. We found no sex effect, challenging previous research on a female bias in chimpanzee tool use. These life-long differences in extractive foraging impacts daily energy budgets, which potentially have significant individual fitness and life history consequences. Additionally, the establishment of long-term individual variation in chimpanzee stone tool use has implications for interpreting archaeological records of hominins. Our findings highlight the importance of longitudinal data from long-term field sites when investigating underlying cognitive and behavioural diversity across individual lifespans and between populations.

animal behavior and cognition↗

bioRxiv2023

Population interconnectivity shapes the distribution and complexity of chimpanzee cumulative culture

While cumulative culture is a hallmark of hominin evolution, its origins can be traced back to our common ancestor with chimpanzees. Here we investigate the evolutionary origins of chimpanzee cumulative culture, and why it remained incipient. To trace cultural transmission among the four chimpanzee subspecies, we compared between-population networks based on genetic markers of recent migration and shared cultural traits. We show that limited levels of interconnectivity favored the emergence of a few instances of cumulative culture in chimpanzees. As in humans, cultural complexification likely happened in steps, with between-community transmission promoting incremental changes and repurposing of technologies. We propose that divergence in social patterns led to increased between-group mobility in Homo, propelling our lineage towards a trajectory of irreversible dependence on cultural exchange and complexification. One-Sentence SummaryPopulation interconnectivity through migration explains the origins of chimpanzee cumulative culture and why it remained incipient

evolutionary biology↗

bioRxiv2023

A network-based analysis of signal use during approach interactions across sexes in chacma baboons (Papio ursinus griseipes)

Greetings in primates fulfil important functions including navigation of rank, maintenance of social relationships, and potentially establishing coalition partnerships. Papio makes a particularly valuable study genus as baboons show variation in greeting, male-male cooperation, philopatry, and social system. However, baboon greeting research has largely focused on male-male interactions, with female approach behaviour neglected except in relation to friendships and grunting. Most if not all signals seen in male-male greetings are also present in approaches between other sex combinations. To understand these signals further, their use in all sex combinations should be explored. We investigated approaches between male and female adult chacma baboons (Papio ursinus griseipes), the only savannah baboon reportedly lacking male-male cooperation, recorded in Gorongosa National Park, Mozambique. We compared male-male greetings with those of other baboon species, identified network clusters of co-occurring signals, and compared male and female approaches more broadly. Male-male approaches were similar to those in other baboon species. We identified several predictable signal combinations, ear-flattening with lip-smacking being a particularly strong signal of benign intent across sexes. Further research comparing greeting across sex combinations and species will help disentangle links between risk, cooperation, and greeting behaviour.

animal behavior and cognition↗

bioRxiv2022

3D genome topologies distinguish pluripotent epiblast and primitive endoderm cells in the mouse blastocyst

The development of embryonic cell lineages is tightly controlled by transcription factors that regulate gene expression and chromatin organisation. To investigate the specialisation of 3D genome structure in pluripotent or extra-embryonic endoderm lineages, we applied Genome Architecture Mapping (GAM) in embryonic stem (ES) cells, extra-embryonic endoderm (XEN) stem cells, and in their in vivo counterparts, the epiblast (Epi) and primitive endoderm (PrE) cells, respectively. We discover extensive differences in 3D genome topology including the formation domain boundaries that differ between Epi and PrE lineages, both in vivo and in vitro, at lineage commitment genes. In ES cells, Sox2 contacts other active regions enriched for NANOG and SOX2 binding sites. PrE-specific genes, such as Lama1 and Gata6, form repressive chromatin hubs in ES cells. Lama1 activation in XEN or PrE cells coincides with its extensive decondensation. Putative binding sites for OCT4 and SNAIL, or GATA4/6, distinguish chromatin contacts unique to embryonic or extra-embryonic lineages, respectively. Overall, 3D genome folding is highly specialised in early development, especially at genes encoding factors driving lineage identity. HighlightsO_LIES and XEN cells have specialised 3D genome structures C_LIO_LIGAM applied in the blastocyst distinguishes Epi and PrE genome structures C_LIO_LILineage specific genes establish cell-type specific chromatin contacts C_LIO_LISpecific chromatin contacts feature putative bindings sites for GATA4/6 in XEN cells and SNAIL in ES cells C_LI

developmental biology↗

bioRxiv2022

Chimpanzee play sequences are structured hierarchically as games

Social play is ubiquitous in the development of many animal species and involves players adapting actions flexibly to their own previous actions and partner responses. Play differs from other behavioural contexts for which fine-scale analyses of action sequences are available, such as tool use and communication, in that its form is not defined by its functions, making it potentially more unpredictable. In humans, play is often organised in games, where players know context-appropriate actions but string them together unpredictably. Here, we use the sequential nature of play elements to explore whether play elements in chimpanzees are structured hierarchically and follow predictable game-like patterns. Based on 5711 play elements from 143 bouts, we extracted individual-level play sequences of 11 Western chimpanzees (Pan troglodytes verus) of different ages from the Bossou community. We detected transition probabilities between play elements that exceeded expected levels and show that play elements form hierarchically clustered and interchangeable groups, indicative of at least six games that can be identified from transition networks, some with different roles for different players. We also show that increased information about preceding play elements improved predictability of subsequent elements, further indicating that play elements are not strung together randomly but that flexible action rules underlie their usage. Thus, chimpanzee play is hierarchically structured in short games which limit acceptable play elements and allow players to predict and adapt to partners actions. This grammar of action approach to social interactions can be valuable in understanding cognitive and communicative abilities within and across species.

animal behavior and cognition↗