Pascale Sicotte

Concordia University Montreal · Faculty of Arts and Science

Intergroup aggression often results in the production of public goods, such as a safe and stable social environment and a home range containing the resources required to survive and reproduce. We investigate temporal variation in intergroup aggression in a growing population of colobus monkeys (Colobus vellerosus) to ask a novel question: “Who step...

The gut microbiota of group-living animals is strongly influenced by their social interactions, but it is unclear how it responds to social instability. We investigated whether social instability associated with the arrival of new males and challenges to the alpha male position could explain differences in the gut microbiota in adult female Colobus...

Primatologists have a long-standing interest in the study of maternal care and nonmaternal handling (NH) of infants stemming from recognition that early social relationships can have enduring consequences. Though maternal care and NH often include expression of similar behaviors, they are regularly studied in isolation from each other with nonoverl...

The gut microbiota of group-living animals is strongly influenced by their social interactions, but it is unclear how it responds to social instability. We investigated whether social instability associated with the immigration of new males and challenges to the alpha male position could explain differences in the gut microbiota in adult female Col...

Animals must learn foraging skills to successfully survive and reproduce but the sources of interindividual variation in learning are poorly understood. For example, there is little consensus on the role motivation plays, even though it is a key factor impacting learning outcomes in humans. Here, we conduct a field experiment on a wild primate to i...

In many social species, intergroup aggression is a cooperative activity that produces public goods such as a safe and stable social environment and a home range containing the resources required to survive and reproduce. In this study, we investigate temporal variation in intergroup aggression in a growing population of colobus monkeys to ask a nov...

Rare behaviors are often missing from published papers, hampering phylogenetic analyses. Here, we report, for the first time, masturbation and same-sex sexual behavior (SSB) in both male and female black-and-white colobus monkeys. We recorded these behaviors during 32 months of observation (1573 h of focal animal sampling) on Colobus vellerosus col...

Analysis of glucocorticoid profiles serves as a valuable, multi-faceted tool for insight into the behavior and physiology of wild populations. Recently, the measurement of fecal glucocorticoid metabolites (FCMs) has exploded in popularity due to its compatibility with noninvasive techniques and remote environments A critical first step is to perfor...

Foraging animals need to quickly assess the costs and benefits of different foraging decisions, including resource quantity, quality, preference, ease of access, dispersion, distance, and predation risk. Social animals also need to take social context into account and adapt foraging strategies that maximize net resource intake and minimize contest...

Cooperative home range defense is common in primates, despite a collective action problem that arises when group members benefit from winning the intergroup encounter regardless of whether they participate. The costs associated with this collective action problem may be mitigated by residing in small groups, residing with kin, or by forming strong...

Infant handling (holding or carrying) by adult males is rare in mammals; however, high levels have been reported in some primates. Though infant handling is a costly behaviour, there are many benefits that male handlers can accrue. Infant handling by males is most conspicuous in platyrrhines and tends to be uncommon in catarrhines. In the latter sp...

Most primates produce one offspring at a time but can overlap investment in consecutive offspring (stacked investment) depending on ecological and/or social conditions. “Direct stacked investment” occurs when a female conceives and gestates a new offspring while a previous infant is still suckling. We investigate direct stacked investment in Colobu...

Premasticated food transfer, when an individual partially breaks down food through chewing and feeds it to another individual, usually mouth-to-mouth, is described widely across human cultures. This behavior plays an important role in modern humans’ strategy of complementary feeding, which involves supplementing maternal milk in infant diets with p...

As our closest evolutionary relatives, nonhuman primates are integral elements in our mythologies, diets and scientific paradigms, yet most species now face an uncertain future through exploitation for the pet and bushmeat trades as well as progressive habitat loss. New information about disease transmission, dietary and economic linkage, and the c...

The gut microbiome is structured by social groups in a variety of host taxa. Whether this pattern is driven by relatedness, similar diets or shared social environments is under debate because few studies have had access to the data necessary to disentangle these factors in wild populations. We investigated whether diet, relatedness or the 1 m proxi...

The gut microbiome is structured by social groups in a variety of host taxa. Whether this pattern is driven by relatedness, similar diets, or shared social environments is under debate because few studies have had access to the data necessary to disentangle these factors. We investigated whether diet, relatedness, or 1-meter proximity networks best...

Host behavior and social factors have increasingly been implicated in structuring the composition of gut microbial communities. In social animals, distinct microbial communities characterize different social groups across a variety of taxa, although little longitudinal research has been conducted that demonstrates how this divergence occurs. Our st...

Host behavior and social factors have increasingly been implicated in structuring the composition of gut microbial communities. In social animals, distinct microbial communities characterize different social groups across a variety of taxa, although little longitudinal research has been conducted that demonstrates how this divergence occurs. Our st...

Animals are hypothesized to search their environments in predictable ways depending on the distribution of resources. Evenly distributed foods are thought to be best exploited with random Brownian movements; while foods that are patchy or unevenly distributed require non-Brownian strategies, such as Lévy walks. Thus, when food distribution changes...

Habitat-wide depletion of food leads to scramble feeding competition and animals can mitigate costs with behavioral adjustments in ranging and activity budgets. In seasonal environments, scramble feeding competition may be more intense in lean seasons leading to shifts in the ranges of neighboring groups and cascading changes for other types of com...

Infant handling behaviors-interactions between infants and non-infants, including touching, holding, carrying, grooming, or play grappling-are observed in an array of nonhuman primate taxa. Both maternal and nonmaternal handling contribute to infant development; yet, research typically addresses these behavioral expressions in isolation. Our study...

Infant handling is predominantly regulated by the level of maternal tolerance for others touching the infant. Thus, infant handling represents a source of maternal flexibility that may vary in response to selective pressures. We compared handling time from mothers and non-mothers, and examined which external factors may be impacting ‘total’ (both m...

Taboos are collective ritual prohibitions or avoidances that are put in place to regulate human action. Taboos are maintained by a fear of supernatural retributions, but can also be upheld by community disapproval. Taboos are by definition social, and can be reshaped and modified by communities. Some ritual prohibitions have positive biodiversity m...

Documenting primate life history characteristics is important because it provides information about traits that affect the timing and rate of reproduction in these long-lived species. This study describes the hormonal correlates of female reproductive events and quantifies for the first time key life history variables for Colobus vellerosus, using...

The rate at which infants develop can vary within species. This variation may be due to differences between infants in their nutritional intake and physiology, or the ability of females to adjust the amount and timing of maternal investment to maximize their lifetime reproductive success. This is the first primate study that uses a large sample siz...

Male infanticide typically occurs when a new male kills infants after taking over a dominant reproductive position in a group. Because females invest heavily during gestation and lactation, the costs of infanticide are high. Thus, Abstract a group. Because females invest heavily during gestation and lactation, the costs of infanticide are high. Thu...

Male takeovers affect male tenure, female mate choice and ultimately, individual reproductive success in group-living primates. In social systems with female philopatry and high male reproductive skew, male takeovers largely determine female mate choice, whereas in species with female dispersal, females have the option of deserting a new male. We f...

Infanticide is only a successful male reproductive strategy if males do not kill their own offspring, resulting in a conflict of interest with females over the disclosure of paternity information to males. Females should mate polyandrously to dilute paternity certainty among potentially infanticidal males. In contrast, males would benefit by develo...

Intergroup variation in social networks can have important implications for inferring the evolution of primate social relationships, but the underpinnings of this variation remain poorly understood. To further our understanding of this topic, we investigated whether intergroup variation in colobus grooming networks was associated with group size, t...

Primate females often inspect, touch and groom others' infants (natal attraction) and they may hold and carry these infants in a manner resembling maternal care (infant handling). While natal attraction and infant handling occur in most wild colobines, little is known about the factors influencing the expression of these behaviors. We examined the...

For primates that lack external signs of oestrus, like many colobine monkeys, documenting life-history characteristics can be of considerable value because they provide information about traits that directly affect survival, as well as the timing or rate of reproduction. Documenting the mating behaviour of the females relative to their endocrine an...

Male Colobus vellerosus compete intensely for access to females, which sometimes leads to mortal wounding. Yet, males often form cooperative relationships to overtake prime-aged males and immigrate into bisexual groups. We investigated the factors that predicted the presence of coalitions and affiliative relationships among males in this species. I...

Kinship shapes female social networks in many primate populations in which females remain in their natal group to breed. In contrast, it is unclear to which extent kinship affects the social networks in populations with female dispersal. Female Colobus vellerosus show routine facultative dispersal (i.e., some females remain philopatric and others d...

We explore the factors influencing the abundance of Colobus vellerosus in 11 forest fragments [Boabeng-Fiema Monkey Sanctuary and 9 surrounding forest fragments (range: 3.2-190 ha)] in the forest-savanna transition zone of Ghana. We used a 'complete' count for the colobus census in the fragments. We determined the fragment sizes using geographic in...

Females that do not experience strong contest competition for food are presumed to form ‘egalitarian’ relationships (i.e., lacking strong, linear dominance hierarchies). However, recent studies of Gorilla beringei beringei (mountain gorilla) have documented relatively strong, linear female dominance hierarchies despite them having a highly folivoro...

The rate at which forest change occurs varies with forest types and time. We measured forest change in a small forest fragment in the forest-savanna transition zone of Ghana. A plot-based survey was conducted to assess tree population dynamics over seven years in the core forest of the Boabeng-Fiema Monkey Sanctuary. A total of 561 trees representi...

A growing body of evidence shows within-population variation in natal dispersal, but the effects of such variation on social relationships and the kin composition of groups remain poorly understood. We investigate the link between dispersal, the kin composition of groups, and proximity patterns in a population of black-and-white colobus (Colobus ve...

Methods. Methods for 1) determining dispersal status based on demographic data, 2) laboratory protocols, and 3) determination of allele sizes, computation of R-values, and kinship classification. (DOCX)

VBA code for within-population simulations. VBA code and sample data in Microsoft Excel for within-population simulations. (XLSM)

VBA code for within-group simulations. VBA code and sample data in Microsoft Excel for within-group simulations. (XLSM)

The threat of infanticide by males is suggested to determine upper group size limits for some folivores because large female aggregations attract immigrating males. When groups get large enough to become multimale, infanticide risk should decline because, all other things being equal, more males should deter outside takeovers and the counterstrateg...

Vigilance often decreases with increasing group size, due to lower predation risk or greater scramble competition for food. A group size effect on vigilance is seldom seen in primates, perhaps because scanning and feeding often occur simultaneously or because the distinction between routine and induced vigilance has not been investigated. We analyz...

Examination of the characteristics and locations of sleeping sites helps to document the social and ecological pressures acting on animals. We investigated sleeping tree choice for four groups of Colobus vellerosus, an arboreal folivore, on 298 nights at the Boabeng-Fiema Monkey Sanctuary, Ghana using five non-mutually exclusive hypotheses: predati...

Dispersal is male-biased in ursine colobus monkeys (Colobus vellerosus), although female dispersal also occurs (Teichroeb et al., 2009). Here we describe the process of male dispersal and its connection with between-group encounters (BGEs, N = 444) and male incursions (when males left their group and approached within 50 m of another group; N = 128...

Male agonistic displays may allow males to assess competitors, females to assess mates, or could be directed at cycling females to sexually coerce them. We analysed the display output of 26 male ursine colobus monkeys (Colobus vellerosus) in four groups over 13-mo at the Boabeng-Fiema Monkey Sanctuary, Ghana. Display indices (including three behavi...

Parasite richness and prevalence in wild animals can be used as indicators of population and ecosystem health. In this study, the gastrointestinal parasites of ursine colobus monkeys (Colobus vellerosus) at the Boabeng-Fiema Monkey Sanctuary (BFMS), Ghana, were investigated. BFMS is a sacred grove where monkeys and humans have long lived in relativ...

Vigilance is thought to have evolved as an antipredator defense but, in primates, conspecific threat often better explains this behavior. We examined vigilance in one group of Colobus vellerosus inhabiting the Boabeng-Fiema Monkey Sanctuary in Ghana. We aimed to (1) describe factors affecting vigilance in this population, and (2) examine the import...

Under the dispersal/foraging efficiency model, colobines are predicted to be 'indifferent mothers', neither facilitating philopatry for their daughters nor evicting them from the natal home range because food competition is thought to be slight. We observed six groups of Colobus vellerosus at the Boabeng-Fiema Monkey Sanctuary in Ghana (2000-2007)...

For group-living mammals, the ecological-constraints model predicts that within-group feeding competition will increase as group size increases, necessitating more daily travel to find food and thereby constraining group size. It provides a useful tool for detecting scramble competition any time it is difficult to determine whether or not food is l...

During a 13-month study period on four groups of Colobus vellerosus at the Boabeng-Fiema Monkey Sanctuary in Ghana, we recorded all instances of male aggression to infants and mothers with infants using focal-animal and ad libitum sampling. Resident males did not attack infants, whereas new immigrant males who became high-ranking and those that imm...

Male testosterone (T) levels are thought to be linked with the mating system, degree of parental care, and male-male aggression in reproductive contexts (The 'challenge hypothesis'; Wingfield et al., 1990). In many species though, T increases associated with mating behavior cannot be separated from those associated with male-male aggression. We tes...

This study describes natal attraction and infant handling in wild ursine colobus (Colobus vellerosus). Focal animal samples were collected from five infants of 1-16 weeks of age (mean: 14.5 focal hours per infant). Group members may be attracted to an infant, but unable to handle it because of resistance from the mother. We thus measured natal attr...

Male Colobus vellerosus are the main participants in intergroup encounters, and lead incursions in neighboring groups during which they attack infants. Extragroup copulations, all-male groups, and male takeover occur in the species. Here, we provide additional information on behaviors associated with male reproductive competition in Colobus vellero...

We explore the applicability of the current socio-ecological model to characterize the social structure of Colobus vellerosus, a folivorous primate. The current socio-ecological model predicts that female social relationships should respond in predictable ways to food abundance and distribution and associated competitive regimes. It appears to succ...

We investigated the occurrence of scramble competition among Colobus vellerosus at Boabeng-Fiema, Ghana. If scramble competition had an impact on feeding efficiency among females, we expected a positive relationship between group size and the proportion of time spent feeding, day journey length, or home range size assuming resource availability is...

We examined the spatial and temporal distribution of the foods of ursine colobus (Colobus vellerosus) at Boabeng-Fiema, Ghana as a means to predict the monopolizablity and usurpability of their food resources. Recent evidence suggests that food may not be limiting for folivorous primates, and that male sexual coercion may be a more important influe...

The forest fragments surrounding the 192-ha Boabeng-Fiema Monkey Sanctuary (BFMS) in central Ghana contain small populations of Colobus vellerosus. Data were collected on activity budget, ranging patterns and habitat use of 3 groups living in these small fragments in August-November 2003, and compared to 3 BFMS groups. Fragment groups spent less ti...

The forest fragments surrounding the Boabeng-Fiema Monkey Sanctuary (BFMS) in central Ghana shelter small populations of Colobus vellerosus. Little is known about these populations or the ability of the fragments to support them, despite the fact that these fragments represent potentially important habitat for the colobus in this region. We compare...

Englilish The Boabeng-Fiema Monkey Sanctuary in central Ghana has been called a classic example of successful ‘‘traditional’’ conservation. Local hunting taboos on two species of primates (the ursine black and white colobus and the Campbell's monkey) are thought to date back to the 1830s when a local oracle instructed the villagers to ‘‘care for th...

The Boabeng-Fiema Monkey Sanctuary (BFMS) is inhabited by a growing population of Ursine colobus (Colobus vellerosus), a species that is listed as vulnerable. Smaller, degraded forest fragments that surround the BFMS also contain C. vellerosus and may provide an important habitat for the monkeys. Our objectives were to 1) determine the current popu...

We describe a case of male takeover in the ursine black-and-white colobus (Colobus vellerosus). In April 2001, an all-male group attacked and eventually invaded our uni-male study group. Aggression increased following the takeover and the former resident male, severely wounded, became peripheral. The youngest immature received severe aggression fro...

The ability to recognize individuals is a prerequisite for analyzing social relationships. We marked five adult and subadult Colobus vellerosus (three in 2002, and two in 2003) at the Boabeng Fiema Monkey Sanctuary, Ghana, to assess the feasibility of dye-marking black-and-white colobus, describe their reactions, and compare some of their behaviors...

group encounters can 1— reflect between-group contest competition for access to limiting, defensible resources, 2 — allow individuals to gather information on the surrounding groups to assess mating or dispersal opportunities or to assess resistance to a possible transfer or takeover, 3 — allow individuals to convey information to the other group a...

1. Mountain gorillas of the Virungas: a short history Kelly J. Stewart, Pascale Sicotte and Martha M. Robbins Part I. Variation in the Social System of Gorillas: 2. Variation in the social system of mountain gorillas: the male perspective Martha M. Robbins 3. Female mate choice in mountain gorillas Pascale Sicotte 4. Dispersal patterns, group struc...

Group size influences foraging efficiency in several primates. We examined the activity budgets of 3 groups of Geoffroy's pied colobus (Colobus vellerosus) at the Boabeng-Fiema Monkey Sanctuary in Ghana to determine whether larger group size induces scramble competition. We studied 2 groups (B1; N = 7-8 and WW; N = 31-33) occupying slightly overlap...

In groups of Gorilla g. beringei, male aggression towards females regularly takes the form of male display. This paper examines male display towards females in two Karisoke study groups (Group 5 and Group BM) in 1989, a period when none of the females were new immigrants. Results are based on 259 hr of focal observations and 121 hr of ad libitum ob...

Forty-seven property owners in Entebbe, Uganda were questioned about vervet monkey activities on their property. Our main objective was to investigate the interactions between humans and vervet monkeys in an agricultural area adjacent to a forest zone. Other studies have reported that farms located within 300 m of a forested boundary probably incur...

For the past three decades the mountain gorillas of Karisoke Research Center have been the subject of many studies focusing on their behaviour and ecology. Long-term observations on known individuals, from birth to death, and data on social behaviour within and between groups have led to an understanding of many aspects of gorilla social structure....

For the past three decades the mountain gorillas of Karisoke Research Center have been the subject of many studies focusing on their behaviour and ecology. Long-term observations on known individuals, from birth to death, and data on social behaviour within and between groups have led to an understanding of many aspects of gorilla social structure....

Frequent urine samples from three habituated free-ranging adult female mountain gorillas were collected during a four-week period in order to characterize, by analysis of urinary hormones, their ovarian cycle, and to diagnose pregnancy. A conceptive cycle and two cycles that did not result in full term pregnancy were monitored. Behavioral and physi...

In mountain gorillas (Gorilla g. beringei), male immigration in bi-sexual units is rare. This paper presents the case of a nearly weaned male infant gorilla who followed his mother in her transfer. This case was recorded in the study population at the Kariske Research Center in 1988. The data come from observation in Group B (on 12 days just prior...

In nonhuman primate groups that utilize crop and food-raiding strategies, the inclusion of human food in the diet can have a pervasive impact on the activity budget. Human food is usually of higher quality and energy per unit than wild food. Thus, metabolic demands may be reached sooner on a human food diet, which in turn leads to improved foraging...

Citation: Sicotte P. and Nissan C. 1998. Femmes et empathie en primatologie: réflexions sur la représentation des femelles primates et des femmes primatologues. Autrement HS 106:77-102.

In bimale groups of mountain gorillas, conflicts between the silverbacks sometimes induce infants and females to interpose between the opponents. This paper describes a set of 40 such interpositions, using data from 380 h of focal observation of the silverbacks in 2 groups at the Karisoke Research Center. Aggressive interactions between males can b...

In gorillas (Gorilla gorilla beringei), male reproductive competition is manifested during inter-group encounters through displays and contact aggression with opposing males and through attempts to control the movement of females between groups. This paper documents the effect of within-group male reproductive competition on male-female relationshi...

This paper examines the behaviors used by male gorillas (G. gorilla beringei) to influence female choice during inter-group encounters. Encounters are related to the acquisition of females rather than to the defense of a group's range. Data on 58 independent encounters confirms that encounters are generally aggressive, but that contact aggression i...