Valérie A M Schoof

York University · Bilingual Biology Program, Department of Multidisciplinary Studies

Resource availability is intricately linked to female reproductive success, and poor timing of reproduction can negatively impact maternal and/or infant survival. Thus, females should exhibit flexibility in the timing of reproduction that reflects local conditions. We examined eight years of data on births, conceptions, mating seasonality, and inte...

Primates are the most colorful members of the Mammalian clade. In vervet monkeys (Chlorocebus pygerythrus), males are characterized by their red penis and blue scrotum. Such color signals are often used in conspecific communication, and thus could be used to convey signaller condition. We quantified scrotal and penile color characteristics using di...

The major histocompatibility complex (MHC) is an important gene complex contributing to adaptive immunity. Studies of platyrrhine MHC have focused on identifying experimental models of immune system function in the equivalent Human Leukocyte Antigen (HLA). These genes have thus been explored primarily in captive platyrrhine individuals from researc...

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...

Highlighting the shared evolutionary relationships between humans and animals — and recognizing that all species, including humans, are unique in their own way — may facilitate caring for and conserving animals by tapping into a human emotion: empathy.

Globally, habitat degradation is accelerating, especially in the tropics. Changes to interface habitats can increase environmental overlap among nonhuman primates, people, and domestic animals and change stress levels in wildlife, leading to changes in their risk of parasite infections. However, the direction and consequences of these changes are u...

Simian primates (monkeys and apes) are typically long-lived animals with slow life histories. They also have varying social organization and can slowly impact their environment by either being seed dispersers or by overbrowsing their food trees. As a result, short-term studies and those focusing on just 1 location only provide a snapshot of simian...

Primates are long-lived animals with complex life histories, which slowly impact their environment through seed dispersal and herbivory. As a result, short-term studies only provide a snapshot of a primate's life and poorly represent their environmental effects. Therefore long-term studies are needed. The need for long-term studies has taken on urg...

Substantial research has shown that while some parasite infections can be fatal to hosts, most infections are sub-clinical and non-lethal. Such sub-clinical infections can nonetheless have negative consequences for the long-term fitness of the host such as reducing juvenile growth and the host’s ability to compete for food and mates. With such effe...

Objective: Circannual variation in reproduction is pervasive in birds and mammals. In primates, breeding seasonality is variable, with seasonal birth peaks occurring even in year-round breeders. Environmental seasonality is reportedly an important contributor to the observed variation in reproductive seasonality. Given that food availability is the...

Despite strong links between sociality and fitness that ultimately affect the size of animal populations, the particular social and ecological factors that lead to endangerment are not well understood. Here, we synthesize approximately 25 years of data and present new analyses that highlight dynamics in forest composition, food availability, the nu...

The availability of food could significantly impact female reproduction, and seasonal variation in this resource can influence the timing of reproductive events. Here we examine the relationship between food availability and the timing of births in vervet monkeys (Chlorocebus pygerythrus) living in a forest-agriculture matrix at Lake Nabugabo, Ugan...

Ecological variation strongly influences female reproductive endocrinology, frequently resulting in seasonal patterns linked to energetic constraints. Such energetic constraints may similarly affect males, but research has emphasized social factors, while largely ignoring ecological influences on male reproduction. We examine the effects of both ec...

Social relationships among immigrant same-sex co-residents have received relatively little atten-tion, particularly for species where males are the dispersing sex. White-faced capuchins (Cebus capucinus) are unusual in that immigrant males form cooperative alliances with co-resident males during intergroup encounters, and also have affiliative and...

The factors that drive within-species variation in animal space use remain poorly understood. A growing body of evidence suggests that both home range attributes and biological interpretations of the home range may depend fundamentally on the scale of analysis. We utilize a multiscale mixed effects modelling framework to examine how seasonal fluctu...

Understanding pathogen transmission is essential to addressing the dynamics of infectious diseases in animal populations. Directly transmitted parasites spread in host populations via 1) contact with infected individuals and 2) contact with contam-inated substrates. Although studies exist that support social or ranging effects on transmission, it i...

Infanticide occurs in a range of primate species, usually in the context of intergroup encounters, group takeovers, or following changes to the male dominance hierarchy. Here we report on two infanticides – one observed and one inferred – during a socially stable period in one group from the Santa Rosa, Costa Rica population of white-faced capuchin...

In a biomedical research environment, research or management procedures may render continuous full contact pairing of rhesus macaques (Macaca mulatta) unfeasible. This study aimed to determine whether separation on a frequent basis or housing in adjacent cages with tactile contact interferes with the behavioral benefits of continuous full contact....

Much attention has been paid to hormonal variation in relation to male dominance status and reproductive seasonality, but we know relatively little about how hormones vary across life history stages. Here we examine fecal testosterone (fT), dihydrotestosterone (fDHT), and glucocorticoid (fGC) profiles across male life history stages in wild white-f...

Reproductive success is linked to dominance in male primates, reflecting the benefits of male competition. However, not all males compete successfully, suggesting that the costs of obtaining and maintaining high dominance status are significant. Here we examine the fecal metabolites of testosterone (fT) and dihydrotestosterone (fDHT) as bioactive a...

Reproductive success is linked to dominance in male primates, reflecting the benefits of male competition. However, not all males compete successfully, suggesting that the costs of obtaining and maintaining high dominance status are significant. Here we examine the fecal metabolites of testosterone (fT) and dihydrotestosterone (fDHT) as bioactive a...

In many wild primates, male dominance rank is correlated with reproductive success. However, not all males compete successfully, suggesting that the costs of obtaining and maintaining high dominance are significant. Testosterone (fT) and dihydrotestosterone (fDHT) are androgens that facilitate male aggression and sexual behavior. Glucocorticoids (f...

Androgens play a role in male reproductive competition, frequently via aggression, while glucocorticoids are associated with the stress response. However, the relationships of these hormones with different sources of competition (intra- vs. intergroup) and dominance status are highly variable. Here, we consider the fecal androgen (fA) and glucocort...

Developments in field methods allow non-invasive assessments of hormone levels in wild animals. Here we highlight social and developmental factors associated with variation in fecal androgen and glucocorticoid (fGC) levels of male white-faced capuchin monkeys in Costa Rica. Alpha males have higher androgen and fGC levels than subordinates, with lev...

Within group social relationships among immigrant same-sex individuals have received relatively little attention, particularly when males are the dispersing sex. White-faced capuchins (Cebus capucinus) are unusual in that males form cooperative alliances during intergroup encounters and are described as having affiliative and egalitarian/tolerant r...

We examined fecal androgen and cortisol levels in three adult male white-faced capuchin monkeys (Cebus capucinus) before and after a non-aggressive rank increase in one habituated group residing in the Santa Rosa Sector of the Área de Conservación Guanacaste, Costa Rica. Fecal samples (n = 116) were collected opportunistically between July 2006 and...

Pair housing for caged macaques in the laboratory generally allows unrestricted tactile contact but, less commonly, may involve limited contact via grooming-contact bars or perforated panels. The purpose of using this protected contact housing, which prevents entry into pair-mates' cages, typically is to accommodate research and management requirem...

Introducing singly housed rhesus macaques (Macaca mulatta) into isosexual pairs is widely considered to improve welfare. The population of laboratory rhesus macaques is heterogeneous on a variety of factors and there is little literature available to directly evaluate the influence of many of these factors on the benefits of pair housing. Subjects...

Parallel dispersal occurs when individuals emigrate together with peers or close kin, or im-migrate into groups containing familiar or closely related individuals. To understand the evo-lution of parallel dispersal in male primates, we explore if parallel dispersal co-occurs with male coalitions, or with other traits that may facilitate coalition f...

This study evaluated the application of positive reinforcement training (PRT) as an intervention for abnormal behaviors in singly housed laboratory rhesus macaques at 2 large primate facilities. Training involved basic control behaviors and body-part presentation. The study compared baseline behavioral data on 30 adult males and 33 adult females co...

We report on the responses of Cebus capucinus in the Santa Rosa Sector of the Area de Conservación Guanacaste, Costa Rica, to the presence of observers over a 4-week period. Study groups were habituated to different degrees: (1) Cerco de Piedra (CP): continuous observations began in 1984; (2) Exclosure (EX): focus of an 18-month study on males from...