Seasonality of reproduction in wild cotton-top tamarins (Saguinus oedipus) in Colombia.

Seasonal availability of resources can influence the timing and success of reproduction in primates. This study examines the annual pattern of conceptions, mid-term (13 weeks) and full-term (26 weeks) pregnancy losses, births, and infant survivorship of the Critically Endangered cotton-top tamarin (Saguinus oedipus) at Proyecto Tití's long-term field site in Santa Catalina, Colombia. Using 18 years of behavior, physical exam, and fecal steroid data (N = 51 females, 168 conceptions, 121 liters), fecal estrone conjugate (E C) and pregnanediol-3-glucuronide (PdG) or progesterone (P4) profiles were examined to investigate the relationships between female reproductive patterns and reproductive success with feeding and climatic data.

Biotic and abiotic drivers of dispersion dynamics in a large-bodied tropical vertebrate, the Western Bornean orangutan.

Understanding of animal responses to dynamic resource landscapes is based largely on research on temperate species with small body sizes and fast life histories. We studied a large, tropical mammal with an extremely slow life history, the Western Bornean orangutan (Pongo pygmaeus wurmbii), across a heterogeneous natural landscape encompassing seven distinct forest types. Our goals were to characterize fluctuations in abundance, test hypotheses regarding the relationship between dispersion dynamics and resource availability, and evaluate how movement patterns are influenced by abiotic conditions.

Responses to Spatial and Temporal Variation in Food Availability on the Feeding Ecology of Proboscis Monkeys (Nasalis larvatus) in West Kalimantan, Indonesia.

Folivorous primates have long been assumed to experience food competition less acutely than frugivores due to their ability to eat leaves, an abundant resource in most forest systems. Consequently, the behavioural responses of leaf-eating primates to variation in food availability are less well characterised than those of frugivores. Recent empirical studies have demonstrated that many colobine species are more affected by food availability and distribution than previously thought; they employ multiple strategies to survive during periods of food scarcity.

Dietary diversity, feeding selectivity, and responses to fruit scarcity of two sympatric Bornean primates (Hylobates albibarbis and Presbytis rubicunda rubida).

Effectively characterizing primate diets is fundamental to understanding primate behavior, ecology and morphology. Examining temporal variation in a species' diet, as well as comparing the responses of different species to variation in resource availability, can enhance understanding of the evolution of morphology and socioecology. In this study, we use feeding data collected over five years to describe the diets of two sympatric Southeast Asian primate species of similar body size: white-bearded gibbons (Hylobates albibarbis) and red leaf monkeys (Presbytis rubicunda rubida), in Gunung Palung National Park, West Kalimantan, Indonesia.

An Assessment of the Population of Cotton-Top Tamarins (Saguinus oedipus) and Their Habitat in Colombia.

Numerous animals have declining populations due to habitat loss, illegal wildlife trade, and climate change. The cotton-top tamarin (Saguinus oedipus) is a Critically Endangered primate species, endemic to northwest Colombia, threatened by deforestation and illegal trade. In order to assess the current state of this species, we analyzed changes in the population of cotton-top tamarins and its habitat from 2005 to 2012.

Sleeping site selection by proboscis monkeys (Nasalis larvatus) in West Kalimantan, Indonesia.

Primates spend at least half their lives sleeping; hence, sleeping site selection can have important effects on behavior and fitness. As proboscis monkeys (Nasalis larvatus) often sleep along rivers and form bands (aggregations of one male groups) at their sleeping sites, understanding sleeping site selection may shed light on two unusual aspects of this species' socioecology: their close association with rivers and their multilevel social organization. We studied sleeping site selection by proboscis monkeys for twelve months at Sungai Tolak, West Kalimantan, Indonesia to test two main hypotheses regarding the drivers of sleeping site selection: reduction of molestation by mosquitoes and anti-predator behavior.

Defining fallback foods and assessing their importance in primate ecology and evolution.

Physical anthropologists use the term "fallback foods" to denote resources of relatively poor nutritional quality that become particularly important dietary components during periods when preferred foods are scarce. Fallback foods are becoming increasingly invoked as key selective forces that determine masticatory and digestive anatomy, influence grouping and ranging behavior, and underlie fundamental evolutionary processes such as speciation, extinction, and adaptation. In this article, we provide an overview of the concept of fallback foods by discussing definitions of the term and categorizations of types of fallback foods, and by examining the importance of fallback foods for primate ecology and evolution.