C P Van Schaik
Biographic Data
| ID | 3139 |
|---|---|
| NAME | C P Van Schaik |
| GIVEN NAMES | C P |
| FAMILY NAME | Van Schaik |
| SIGNATURE | VAN SCHAIK C P |
| AFFILIATIONS | University of Zurich |
| ORCID | 0000-0001-5738-4509 |
| VERIFIED | Yes |
| TOTAL WORKS | 104 |
| TOTAL CITATIONS | 1130 |
| AUTHOR COUNT | 104 |
| EDITOR COUNT | 0 |
| FIRST PUBLICATION YEAR | 1983 |
| LATEST PUBLICATION YEAR | 2026 |
| H-INDEX | 19 |
Hair Steroid Signatures of Cooperative Breeding in Male and Female Common Marmosets (Callithrix jacchus)
Slowly but Surely
The high energy costs of brains suggest that a species' current brain size is adaptive. However, although the comparative data for mammals suggest a positive effect on fitness in larger‐brained species because of higher adult survival and thus longer lifespan, it also reveals two negative effects, namely later age at first reproduction owing to slower development and a tendency towards reduced reproductive allocation owing to larger newborns. Her…
Cooperative Breeding as a Likely Early Catalyst of Human Evolution
Unlike any other great ape, humans give birth to large, secondarily altricial babies, show precocial social development, have bigger brains that require a long maturation period, and engage in cooperative breeding (CB). These traits, which characterize the human adaptive complex, are intricately linked and must have mutually reinforced each other over evolutionary time. Here, we use recent evidence from paleontology, developmental psychology, and…
Alternative reproductive tactics of unflanged and flanged male orangutans revisited
In many slowly developing mammal species, males reach sexual maturity well before they develop secondary sexual characteristics. Sexually mature male orangutans have exceptionally long periods of developmental arrest. The two male morphs have been associated with behavioral alternative reproductive tactics, but this interpretation is based on cross‐sectional analyses predominantly of Northwest Sumatran populations. Here we present the first longi…
After the smoke has cleared
As climate change continues to fundamentally alter resource landscapes, the ability to flexibly respond to spatio-temporal changes in the distribution of preferred food sources is increasingly important for the overall health and fitness of animals living in seasonal, variable, and/or changing environments. Here, we investigate the effects of an uncharacteristically long period of fruit scarcity, following widespread thick haze caused by peat and…
Four levers of reciprocity across human societies
This paper surveys five human societal types – mobile foragers, horticulturalists, pre-state agriculturalists, state-based agriculturalists and liberal democracies – from the perspective of three core social problems faced by interacting individuals: coordination problems, social dilemmas and contest problems. We characterise the occurrence of these problems in the different societal types and enquire into the main force keeping societies togethe…
Cooperation in large‐scale human societies — What, if anything, makes it unique, and how did it evolve
To resolve the major controversy about why prosocial behaviors persist in large‐scale human societies, we propose that two questions need to be answered. First, how do social interactions in small‐scale and large‐scale societies differ? By reviewing the exchange and collective‐action dilemmas in both small‐scale and large‐scale societies, we show they are not different. Second, are individual decision‐making mechanisms driven by self‐interest? We…
Why Class Formation Occurs in Humans but Not among Other Primates
Determining overweight and underweight with a new weight‐for‐height index in captive group‐housed macaques
Housing primates in naturalistic groups provides social benefits relative to solitary housing. However, food intake may vary across individuals, possibly resulting in overweight and underweight individuals. Information on relative adiposity (the amount of fat tissue relative to body weight) is needed to monitor overweight and underweight of group‐housed individuals. However, the upper and lower relative adiposity boundaries are currently only kno…
Evaluating the self‐domestication hypothesis of human evolution
"Self-domestication" has been invoked to understand important aspects of human evolution, integrating physiological, behavioral, and morphological information in a novel way. It proposes that selection for reduced aggression on animals undergoing domestication provides a model for selection favoring prosocial behaviors in humans and for a set of seemingly independent features, which arose as a result of developmental correlation. We review the hi…
Animal cultures
For humans we implicitly assume that the way we do things is the product of social learning and thus cultural. For animals, this conclusion requires proof. Here, we first review the most commonly used procedure for documenting animal culture: the method of exclusion, which charts geographic behavioral variation between populations as evidence for culture. Using published data, we show that, whereas it is an adequate proof of principle, the method…
Evolutionary Origins of Morality
The aim of this contribution is to explore the origins of moral behavior and its underlying moral preferences and intuitions from an evolutionary perspective. Such a perspective encompasses both the ultimate, adaptive function of morality in our own species, as well as the phylogenetic distribution of morality and its key elements across primates. First, with regard to the ultimate function, we argue that human moral preferences are best construe…
The slow ape
Validation of a field-friendly extraction and storage method to monitor fecal steroid metabolites in wild orangutans
Resilience of experimentally seeded dietary traditions in wild vervets
Controlled laboratory experiments have delivered extensive and compelling evidence for the diffusion and maintenance of socially learned behavior in primates and other animals. Such evidence is rarer in the wild, but we show that a behavior seeded in a majority of individuals within vervet monkey (Chlorocebus pygerythus) groups may be sustained across several years. Here, we report results of two natural fission events in such groups that offer n…
Explaining the Paradox of Neophobic Explorers
The social organization of Homo ergaster
Life history, cognition and the evolution of complex foraging niches
The Conditions Favoring Between-Community Raiding in Chimpanzees, Bonobos, and Human Foragers
Contrasting responses to novelty by wild and captive orangutans
Several studies have suggested that wild primates tend to behave with caution toward novelty, whereas captive primates are thought to be less neophobic, more exploratory, and more innovative. However, few studies have systematically compared captive and wild individuals of the same species to document this "captivity effect" in greater detail. Here we report the responses of both wild and captive orangutans to the same novel items. Novel objects …
Validation of an acoustic location system to monitor Bornean orangutan ( Pongo pygmaeus wurmbii ) long calls
The long call is an important vocal communication signal in the widely dispersed, semi-solitary orangutan. Long calls affect individuals' ranging behavior and mediate social relationships and regulate encounters between dispersed individuals in a dense rainforest. The aim of this study was to test the utility of an Acoustic Location System (ALS) for recording and triangulating the loud calls of free-living primates. We developed and validated a d…
Why do orangutans leave the trees? Terrestrial behavior among wild Bornean orangutans ( Pongo pygmaeus wurmbii ) at Tuanan, Central Kalimantan
Orangutans (genus Pongo) are the largest arboreal mammals, but Bornean orangutans (P. pygmaeus spp.) also spend time on the ground. Here, we investigate ground use among orangutans using 32,000 hr of direct focal animal observations from a well-habituated wild population of Bornean orangutans (P. p. wurmbii) living in a closed-canopy swamp forest at Tuanan, Central Kalimantan, Indonesia. Ground use did not change with increasing observation time …
Chimpanzees' Bystander Reactions to Infanticide
Zoon Politikon
We provide the most up-to-date evidence available in various behavioral fields in support of the hypothesis that the emergence of bipedalism and cooperative breeding in the hominin line-together with environmental developments that made a diet of meat from large animals adaptive as well as cultural innovation in the form of fire and cooking-created a niche for hominins in which there was a high return for coordinated, cooperative scavenging and h…
Infanticide by Males and its Implications
"In this book, case studies and reviews confirm the adaptive nature of infanticide in males in primates and other animals, and help to predict which species should be vulnerable to it. Much of the book is devoted to exploring the evolutionary consequences of the threat of infanticide by males for social and reproductive behavior and physiology. Written for graduate students and researchers in animal behavior, behavioral ecology, biological anthro…
Intrasexual competition and canine dimorphism in anthropoid primates
A number of factors, including sexual selection, body weight, body-weight dimorphism, predation, diet, and phylogenetic inertia have been proposed as influences on the evolution of canine dimorphism in anthropoid primates. Although these factors are not mutually exclusive, opinions vary as to which is the most important. The role of sexual selection has been questioned because mating system, which should reflect its strength, poorly predicts vari…
Fission-Fusion Dynamics
Renewed interest in fission-fusion dynamics is due to the recognition that such dynamics may create unique challenges for social interaction and distinctive selective pressures acting on underlying communicative and cognitive abilities. New frameworks for integrating current knowledge on fission-fusion dynamics emerge from a fundamental rethinking of the term "fission-fusion" away from its current general use as a label for a particular modal typ…
Evolution of Primate Social Systems
Functional ecology and evolution of hominoid molar enamel thickness
Interpreting hominid behavior on the basis of sexual dimorphism
Life history of wild Sumatran orangutans (Pongo abelii)
Competition, coalitions and canine size in primates
The conditions for tool use in primates
How Our Ancestors Broke through the Gray Ceiling
The “expensive brain” framework proposes that the costs of an increase in brain size can be met by any combination of increasing the total energy turnover or reducing energy allocation to other expensive functions, such as maintenance (digestion), locomotion, or production (growth and reproduction). Here, we explore its implications for human evolution. Using both comparative data on extant mammals and life-table simulations from wild extant apes…
Intra‐and interpopulational differences in orangutan ( Pongo pygmaeus ) activity and diet
Tool manufacture and use have been described for wild orangutans ( Pongo pygmaeus ), with appreciable interpopulational differences in tool complexes. The ecological factors that contribute to these differences require investigation. Significant interpopulational differences in diet suggest that ecological factors contribute to variation in tool‐based insect foraging. Using 4 years of behavioral data from the Suaq Balimbing Research Station (Suma…
Foraging and ranging behavior during a fallback episode
Periodic episodes of food scarcity may highlight the adaptive value of certain anatomical traits, particularly those that facilitate the acquisition and digestion of exigent fallback foods. To better understand the selective pressures that favored the distinctive dental and locomotor morphologies of gibbons and orangutans, we examined the foraging and ranging behavior of sympatric Hylobates albibarbis and Pongo pygmaeus wurmbii during an episode …
Allomaternal care, life history and brain size evolution in mammals
The Expensive Brain
Fallback foods of temperate‐living primates
Only a few primate species thrive in temperate regions characterized by relatively low temperature, low rainfall, low species diversity, high elevation, and especially an extended season of food scarcity during which they suffer from dietary stress. We present data of a case study of dietary strategies and fallback foods in snub‐nosed monkeys ( Rhinopithecus bieti ) in the Samage Forest, Northwest Yunnan, PRC. The snub‐nosed monkeys adjusted inta…
Zoon Politikon
We provide the most up-to-date evidence available in various behavioral fields in support of the hypothesis that the emergence of bipedalism and cooperative breeding in the hominin line-together with environmental developments that made a diet of meat from large animals adaptive as well as cultural innovation in the form of fire and cooking-created a niche for hominins in which there was a high return for coordinated, cooperative scavenging and h…
Orangutan Home Range Size and Its Determinants in a Sumatran Swamp Forest
Development of ecological competence in Sumatran orangutans
Data on orangutans (Pongo pygmaeus abelii) living in a Sumatran swamp forest yield an estimated median interbirth interval of at least 8 years, concurring with findings from other sites. This longest known mammalian interbirth interval appears due to maternal amenorrhea during the long exclusive dependence of the offspring. We describe the development of various components of offspring independence. In this arboreal ape, 3-year-olds had largely r…
Life history costs and benefits of encephalization
Geographic variation in tool use on Neesia fruits in orangutans
Geographic variation in the presence of skilled behavior may reflect geographic variation in genetic predispositions or ecological conditions (accompanied by reliable expression during development), or it may reflect the vagaries of invention and the appropriate social conditions for persistence. In this study, we compare the feeding techniques and tool‐using skills used by orangutans to extract the nutritious seeds from Neesia fruits between Sua…
Variation in brain size and ecology in Pongo
Tolerant food sharing and reciprocity is precluded by despotism among bonobos but not chimpanzees
Tolerant food sharing among human foragers can largely be explained by reciprocity. In contrast, food sharing among chimpanzees and bonobos may not always reflect reciprocity, which could be explained by different dominance styles: in egalitarian societies reciprocity is expressed freely, while in more despotic groups dominants may hinder reciprocity. We tested the degree of reciprocity and the influence of dominance on food sharing among chimpan…
Bimorphism in Male Verreaux’s Sifaka in the Kirindy Forest of Madagascar
The social organization of Homo ergaster
Social organization and the evolution of cumulative technology in apes and hominins
How to explain the unusually late age at skill competence among humans
Party size and early detection of predators in sumatran forest primates
Why Are Diurnal Primates Living in Groups?
There are two main competing theories on the evolution of group living in diurnal nonhuman primates. The first theory claims that predation avoidance favours group living, whereas there are only disadvantages to feeding in a group and feeding competition increases with group size. The second theory claims that there is a feeding advantage to group living deriving from communal defence of high-quality food patches and that predation is not importa…
Interannual variability in fruit abundance and the reproductive seasonality in Sumatran Long‐tailed macaques (Macaca fascicularis)
In an environment with a seasonal food supply, most primate species show birth peaks which precede the peak food period by some two to five months. Sumatran Long‐tailed macaques (Macaca fascicularis), however, showed birth peaks during or after the fruit peak. Years of high birth rates and early birth peaks alternated with years of low birth rates and late peaks. The timing of births was strongly influenced by a female's condition, which depends …
Recognizing the Many Faces of Primate Food Competition
Social rank and sex ratio of captive long‐tailed macaque females ( Macaca fascicularis )
Variation in birth sex ratios in primates can be accounted for by two hypotheses: the local resource competition hypothesis [Silk: American Naturalist 121:56–66, 1983] and the hypothesis of Trivers & Willard [Science 179:90–92, 1973] concerning the maternal effect on the quality of a male. We examined the effects of female dominance rank on aspects of reproduction in three well‐established captive groups of long‐tailed macaques ( Macaca fascicula…
Functional aspects of reconciliation among captive long‐tailed macaques ( Macaca fascicularis )
After an agonistic conflict between two animals, they may exchange affiliative social contacts. The function of this reconciliation behavior is thought to be the repair of the social relationship between the two opponents. We examined the hypothesis that reconciliation is socially effective because it may also lead to a reduction of the victim's acute stress. Reconciliation was studied in a well‐established captive group of long‐tailed macaques (…
Population status of the Simeulue monkey ( Macaca fascicularis fusca )
The oceanic island of Simeulue, west of Sumatra, is inhabited by a distinct subspecies of the long‐tailed macaque ( Macaca fascicularis fusca ) [Miller, 1903]. In January 1982 and March 1984, a survey was conducted to establish its population status. The monkey is morphologically different from other Sunda shelf M. fascicularis populations. In productive habitats, it lives in small groups (10–15 individuals) and reaches a density of more than one…
The Evolution of Monogamy in Large Primates
Monogamy among the large primates is not accompanied by high levels of male care for infants. The selective pressures that have led to its evolution in this case are far from clear. In this paper, we evaluate and test four different hypotheses. Monogamy in these species did not evolve because males are unable to defend access to more than one female. Hence, it must be related to behavioural services provided by the male which substantially increa…
A pilot study of the social correlates of levels of urinary cortisol, prolactin, and testosterone in wild long-tailed macaques (Macaca fascicularis)
Competitive regimes and female bonding in two species of squirrel monkeys (Saimiri oerstedi and S. sciureus)
Territorial behavior in Southeast Asian langurs
Between‐group antagonism or territoriality in primates may serve two different but compatible functions: resource defense or mate defense. Females are expected to be involved more strongly in the first, males in the second. The resource defense hypothesis predicts that home range overlap should decrease as defensibility and population density increase, and that females should be involved in hostile between‐group interactions. The mate defense hyp…
Intrasexual competition and canine dimorphism in anthropoid primates
A number of factors, including sexual selection, body weight, body-weight dimorphism, predation, diet, and phylogenetic inertia have been proposed as influences on the evolution of canine dimorphism in anthropoid primates. Although these factors are not mutually exclusive, opinions vary as to which is the most important. The role of sexual selection has been questioned because mating system, which should reflect its strength, poorly predicts vari…
The Phenology of Tropical Forests
Most tropical woody plants produce new leaves and flowers in bursts rather than continuously, and most tropical forest communities display seasonal variation in the presence of new leaves, flowers, and fruits. This patterning suggests that phenological changes represent adaptations to either biotic or abiotic factors. Biotic factors may select for either a staggering or a clustering of the phenological activity of individual plant species. We rev…
Canine dimorphism
Canine dimorphism in many primates is exaggerated, with males possessing enormous, sharp canines that project far beyond the occlusal plane of the other teeth and females having smaller, less projecting canines. Ever since Darwin, 1 canine dimorphism generally has been attributed to sexual selection. However, recent analyses suggest that the evolution of canine dimorphism is complex and that the sexual selection hypothesis is only part of the sto…
Infanticide
Chimpanzee cultures
Competition, coalitions and canine size in primates
The Social Systems of Gregarious Lemurs
The gregarious lemurs of Madagascar show a lack of convergence with anthropoid primates in several social, demographic, morphological and ecological features. They lack sexual dimorphism in canine and body size, and live in groups with equal adult sex ratios that can vary in composition from pairs to larger units. In most species, females dominate males, and have brief and often synchronized estruses. Finally, lemurs are often active during both …
Male care in primates
Male care in primates
The evolution of female social relationships in nonhuman primates
Interpreting hominid behavior on the basis of sexual dimorphism
Intrasexual competition and body weight dimorphism in anthropoid primates
Body weight dimorphism in anthropoid primates has been thought to be a consequence of sexual selection resulting from male-male competition for access to mates. However, while monogamous anthropoids show low degrees of weight dimorphism, as predicted by the sexual selection hypothesis, polygynous anthropoids show high variation in weight dimorphism that is not associated with measures of mating system or sex ratio. This observation has led many t…
The socioecology of fission-fusion sociality in Orangutans
The conditions for tool use in primates
Biology (91 works) · Primate Behavior and Ecology (91 works) · Ecology (54 works) · Ecology (49 works) · Zoology (44 works) · Evolutionary biology (36 works) · Animal Behavior and Reproduction (33 works) · Psychology (33 works) · Animal Vocal Communication and Behavior (31 works) · Demography (31 works)