Cyril Grueter

Cyril Grueter
University of Western Australia | UWA

About

139
Publications
31,822
Reads
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Introduction
My primary research interests include the evolution of primate/human sociality and the behavioral mechanisms responsible for the maintenance of social cohesion. My particular interests revolve around the evolution and functional significance of meta-group social organization which describes cases in which individuals of different social units interact and collaborate to varying degrees and in some cases form higher-level groupings such as multilevel societies.
Additional affiliations
October 2014 - present
University of Western Australia
Position
  • Associate Professor (Senior Lecturer)
April 2012 - present
University of Western Australia
Position
  • Professor (Assistant)
January 2012 - April 2012
Chinese Academy of Sciences
Position
  • Researcher

Publications

Publications (139)
Article
Full-text available
Allomaternal care of infants is widely observed among non-human primates. This behavior can take diverse forms and functions and involve various types of caregivers. Here we focus on a multimale-multifemale group of Taihangshan macaque (Macaca mulatta tcheliensis) in a climatically harsh, high-latitude environment in northern China. We reported a c...
Article
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Traditionally, the genus Rhinopithecus (Milne‐Edwards, 1872, Primates, Colobinae) included four allopatric species, restricted in their distributions to China and Vietnam. In 2010, a fifth species, the black snub‐nosed monkey (Rhinopithecus strykeri) was discovered in the Gaoligong Mountains located on the border between China and Myanmar. Despite...
Article
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Water plays a vital role in many aspects of sustaining life, including thermoregulation. Given that increasing temperatures and more extreme weather events due to climate change are predicted to influence water availability, understanding how species obtain and use water is critical. This is especially true for endangered species in small isolated...
Chapter
The Colobines are a group of Afroeurasian monkeys that exhibit extraordinary behavioural and ecological diversity. With long tails and diverse colourations, they are medium-sized primates, mostly arboreal, that are found in many different habitats, from rain forests and mountain forests to mangroves and savannah. Over the last two decades, our unde...
Article
Full-text available
Simple Summary: The size of primate 'harems' varies considerably, both inter-and intra-specifically. Previous studies have shown that females prefer high-quality males and that high-quality males are superior in inter-male competition, leading to them having a larger harem size. Based on eleven years of observations of Yunnan snub-nosed monkeys (Rh...
Article
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Group-contingent prosociality pervades human societies but the payoffs associated with inter-group tolerance and cooperation act as counterforces. Kinship terms (e.g. 'brother') and affiliative terms (e.g. 'mate') have been proposed to function to create strong bonds among in-group members but it is unknown if they play a role in establishing or st...
Article
Decades of research have led to a solid understanding of the social systems of gregarious apes: chimpanzees, bonobos, gorillas, and gibbons. As field studies have increasingly collected data from multiple neighboring habituated groups, genetic and social interconnections have been revealed. These findings provide a more nuanced picture of intergrou...
Article
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Animal communication has long been thought to be subject to pressures and constraints associated with social relationships. However, our understanding of how the nature and quality of social relationships relates to the use and evolution of communication is limited by a lack of directly comparable methods across multiple levels of analysis. Here, w...
Article
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Understanding variation in host-associated microbial communities is important given the relevance of microbiomes to host physiology and health. Using 560 fecal samples collected from wild chimpanzees (Pan troglodytes) across their range, we assessed how geography, genetics, climate, vegetation, and diet relate to gut microbial community structure (...
Article
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Two mechanisms have been proposed to explain why scramble competition can increase the travel requirements of individuals within larger groups. Firstly, individuals in larger groups may be more likely to encounter food sites where other group members have already eaten, leading to greater asynchronous “individual” travel to find fresh sites. Second...
Article
Objectives Although fermented food use is ubiquitous in humans, the ecological and evolutionary factors contributing to its emergence are unclear. Here we investigated the ecological contexts surrounding the consumption of fruits in the late stages of fermentation by wild primates to provide insight into its adaptive function. We hypothesized that...
Article
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In species with flexible grouping dynamics (i.e., fission-fusion), party (or subgroup) size is often shaped by available resources. Food resources are thought to limit party size in a range of mammalian species, reflecting a strategy of reducing feeding competition. In montane habitats, where food is highly seasonal, we may expect to see strong eff...
Article
While the ability of naturally ranging animals to recall the location of food resources and use straight-line routes between them has been demonstrated in several studies [1, 2], it is not known whether animals can use knowledge of their landscape to walk least-cost routes [3]. This ability is likely to be particularly important for animals living...
Article
Objectives: Social animals often have dominance hierarchies, with high rank conferring preferential access to resources. In primates, competition among males is often assumed to occur predominantly over reproductive opportunities. However, competition for food may occur during food shortages, such as in temperate species during winter. Higher-rank...
Article
Full-text available
Threats to biodiversity are well documented. However, to effectively conserve species and their habitats, we need to know which conservation interventions do (or do not) work. Evidence-based conservation evaluates interventions within a scientific framework. The Conservation Evidence project has summarized thousands of studies testing conservation...
Article
Competition for food is often a cost associated with living in a group, and can occur in an indirect (scramble) or direct (contest) form. We investigated feeding competition in a supergroup of Rwenzori black-and-white colobus monkeys ( Colobus angolensis ruwenzorii ) in Rwanda, with the aim of establishing whether freedom from scramble competition...
Article
Full-text available
When preferred foods are scarce, one strategy employed by primates is to switch to an alternative food item of lower quality or preferability, i.e., a fallback food. In the montane rainforest of Nyungwe National Park in southwestern Rwanda, Rwenzori black-and-white colobus (Colobus angolensis ruwenzorii) (hereafter Rwenzori colobus) form a supergro...
Article
Recent improvements in tracking technologies have resulted in a growing number of fine-scale animal movement studies in a variety of fields, from wildlife management to animal cognition. Most studies assume that an animal's ‘optimal’ foraging route is linear, ignoring the role the energy landscape can play in influencing movement efficiency. Our ob...
Article
Multilevel societies (MLSs), stable nuclear social units within a larger collective encompassing multiple nested social levels, occur in several mammalian lineages. Their architectural complexity and size impose specific demands on their members requiring adaptive solutions in multiple domains. The functional significance of MLSs lies in their memb...
Article
Primates display broad diversity in their social organization. The social groups of a few primate species are organized in a multilevel fashion, with large groups composed of multiple, core one‐male units (OMUs). A characteristic of multilevel societies is that the higher levels can include hundreds of individuals. The Rwenzori black‐and‐white colo...
Article
Full-text available
Group-living animals face a number of threats from extragroup conspecifics: from individuals seeking mating opportunities to rival groups attempting to access limited resources. The consequences of intergroup interactions can therefore include loss of mates, increased energy expenditure, and injury or death. There is increasing evidence that aggres...
Article
Full-text available
Urban living is often thought to promote incivility, but the existing sociological evidence paints a mixed picture. We aimed to examine the urban incivility phenomenon from an evolutionist’s perspective. Small communities are expected to show a higher incidence of helping because the applicability of theories such as kin selection, direct reciproci...
Article
Full-text available
In mammals characterized by a mating system in which a single male monopolizes reproduction, infanticide is reported to occur following a male take-over, often resulting in females returning to oestrus more rapidly than if their infant has survived. However, over the course of a 17-year study of golden snub-nosed monkeys, Rhinopithecus roxellana, a...
Article
Most primates experience seasonal fluctuations in the availability of food resources and face the challenge of balancing energy expenditure with energy gain during periods of resource scarcity. This is likely to be particularly challenging in rugged, montane environments, where available energy is relatively low and travel costs are high. Chimpanze...
Article
Full-text available
Anthropogenic changes and fragmentation of natural habitats often exert a negative effect on resource availability and distribution, and the nutritional ecology and feeding behavior of nonhuman primates. The goals of this study are to examine food choice and to identify the nutritional profile of foods consumed by the Critically Endangered black sn...
Article
Full-text available
Educational attainment is associated with unconditional helping behaviour - Volume 1 - Grace Westlake, David Coall, Cyril C. Grueter
Article
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Both observational and indirect evidence are widely used to determine the diets of wild animals. Direct observations are often assumed to provide the most comprehensive reflection of diet, but many wild animals are logistically challenging to observe. Despite the regular use of observational and indirect methods for inferring diet in wild animals,...
Article
Full-text available
The conservation of endangered species can benefit from a clear understanding of the quantity and distribution of their main foods. The population of mountain gorillas (Gorilla beringei beringei) living in the Virunga Massif of Rwanda, Uganda, and Democratic Republic of Congo has doubled in size since the 1980s, due to success in conservation effor...
Preprint
Recent improvements in tracking technologies have resulted in a growing number of fine-scale animal movement studies in a variety of fields from wildlife management to animal cognition. Most studies assume that an animal's optimal foraging route is linear, ignoring the role the energy landscape can play in influencing movement efficiency. Our objec...
Preprint
While the ability of naturally ranging animals to recall the location of food resources and use straight-line routes between them has been demonstrated in several studies, it is not known whether animals can use knowledge of their physical landscape to plan least-cost routes. This ability is likely to be particularly important for animals living in...
Article
High densities of large herbivores can have detrimental effects on plant biomass. Understanding the relationship between animal densities and plant distribution and abundance is essential for the conservation of endangered species and ecosystems. Mountain gorilla censuses conducted for different periods in the last three decades have revealed a ste...
Article
Males must partition their limited reproductive investments between traits that promote access to females (sexual ornaments and weapons) and traits that enhance fertilization success, such as testes and ejaculates. Recent studies show that if the most weaponized males can monopolize access to females through contest competition, thereby reducing th...
Article
Full-text available
Almost all primates experience seasonal fluctuations in the availability of key food sources. However, the degree to which this fluctuation impacts foraging behavior varies considerably. Eastern chimpanzees (Pan troglodytes schweinfurthii) in Nyungwe National Park, Rwanda, live in a montane forest environment characterized by lower primary producti...
Article
Correlational models are widely used to predict changes in species' distribution, but generally have failed to address the comprehensive effects of anthropogenic activities, climate change, habitat connectivity and gene flow on wildlife sustainability. Here, we used integrated approaches (MAXENT model, circuit model and genetic analysis) to assess...
Article
Full-text available
Recent advances in niche theory have stressed the importance of understanding dietary generalism at multiple levels, including the range of habitat and foods exploited by a species, foods exploited within populations, and patterns of nutrient intake. Here we apply this framework to examine the dietary strategy of the Macaca mulatta, a primate speci...
Article
Full-text available
While regular allomaternal nursing (suckling) has been documented in a number of rodent and carnivore species, as well as in some prosimians, New World monkeys, and humans, it is not common in Old World monkeys and apes. Here, we present a detailed field study of allomaternal nursing in golden snub-nosed monkeys ( Rhinopithecus roxellana , Colobina...
Article
Objectives Infant handling describes cases in which youngsters are temporarily removed from the care of their mothers and “taken care of” (held, carried, etc.) by other conspecifics. Handlers may gain indirect fitness benefits from these actions and can practice mothering skills, thereby improving the odds of survival of their own infants. Great ap...
Article
Full-text available
Vocal individuality is a prerequisite for individual recognition, especially when visual and chemical cues are not available or effective. Vocalizations encoding information of individual identity have been reported in many social animals and should be particularly adaptive for species living in large and complexly organized societies. Here, we exa...
Article
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Abstract The effect of feeding competition on foraging efficiency is an important link between ecological factors and the social organization of gregarious species. We examined the effects of group size on daily travel distances, activity budgets, and energy intake of mountain gorillas in Rwanda. We measured daily travel distances of five groups, a...
Article
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China is facing an unprecedented set of challenges in balancing the effects of economic development and global climate change with environmental protection and maintaining biodiversity. Although positive steps have been undertaken to remedy this situation, currently 80% of China’s 25 extant primate species are threatened, 15–18 species have populat...
Article
Full-text available
Intergroup interactions in social animals can vary from hostile to affiliative and may be influenced by factors such as competitive ability, resource values and existing intergroup relationships. Despite the potential for intergroup interactions to affect individual fitness and group stability, few studies have comprehensively tested how social, de...
Article
Male–male interactions in mixed‐sex groups of social mammals are typically characterized by a mix of hostility and affiliation, as a result of inherent conflicts over mating opportunities, and the costs and benefits of social alliances, co‐operative behaviors, and coalitionary defense. In species of nonhuman primates that form all‐male groups, it i...
Article
In group-living species, encounters with extragroup rivals can be one of the riskiest actions in which individuals participate. Different group members often have different incentives to participate during intergroup interactions, and individuals with fewer payoffs of competition, including those of the smaller sex and/or lower rank, may ‘free-ride...
Article
Space use in mammals may be influenced not only by their primary foods, but also by localized sources of physiologically critical resources such as sodium‐rich plants. We examined how sodium acquisition influences habitat use in mountain gorillas (Gorilla beringei) in Rwanda which have increased the amount of time they forage on community land outs...
Article
The social organization of natural groups of Rhinopithecus bieti (Yunnan snub-nosed monkey) is virtually unknown. We studied the demography and social structure of a free-ranging group at Samage Forest, China, for nearly 2 years. This study confirmed that R. bieti exhibits a multilevel social organization of core 1-male units (OMUs) that congregate...
Article
Full-text available
A small number of primate species including snub-nosed monkeys (colo-bines), geladas (papionins) and humans live in multilevel societies (MLSs), in which multiple one-male polygamous units (OMUs) coexist to form a band, and non-breeding males associate in bachelor groups. Phylogenetic reconstructions indicate that the papionin MLS appears to have e...
Article
Grueter et al. introduce complex animal societies with different grouping levels.
Chapter
Environmental seasonality refers to variation in climate patterns (precipitation levels and temperature), solar radiation, and day length that prompt plant phenological changes and thus changes in food supply (most notably fruit and young leaves). This has direct repercussions on primate behavior and ecology, such as diet, ranging behavior, activit...
Article
Full-text available
Many species of primates are considered seasonal breeders, but the set of factors, such as food availability, day length and temperature, that influence the timing of reproductive events for both wild and captive individuals remains unclear. Here, we examine the role of factors in shaping breeding patterns in Rhinopithecus roxellana , a temperate c...
Data
Dataset All the observed birthdates for captive groups in zoos and wildlife parks; Dataset used for the Figs. 1, 2 and 3.
Article
Full-text available
Altruism toward strangers is considered a defining feature of humans. However, manifestation of this behaviour is contingent on the costliness of the selfless act. The extent of altruistic tendencies also varies cross-culturally, being more common in societies with higher levels of market integration. However, the existence of local variation in se...
Article
Full-text available
The question of whether any species except humans exhibits culture has generated much debate, partially due to the difficulty of providing conclusive evidence from observational studies in the wild. A starting point for demonstrating the existence of culture that has been used for many species including chimpanzees and orangutans is to show that th...
Article
Eastern gorillas (Gorilla beringei) are among the few mammal species that seasonally consume large quantities of young bamboo shoots, which are a rich source of energy. Here, we document how the consumption of bamboo shoots coincides with changes in behavior of adult mountain gorillas (Gorilla beringei beringei) monitored by the Dian Fossey Gorilla...
Article
Full-text available
Although the evolutionary history of primates in China dates to the Eocene, and includes major radiations of lorisids, hominoids, cercopithecines, and colobines during the Miocene, Pliocene, and Pleistocene, extensive human-induced habitat change and deforestation over the past few centuries has resulted in 22 of 25 extant species listed as threate...
Article
In many primate species that form one-male breeding units (OMUs), the threat of a takeover by a bachelor male represents a major challenge to group stability and individual reproductive success. In the case of snub-nosed monkeys, which live in large multilevel or modular societies (MLS) comprising several OMUs that travel, feed and rest together an...