Factors influencing terrestriality in primates of the Americas and Madagascar.

Among mammals, the order Primates is exceptional in having a high taxonomic richness in which the taxa are arboreal, semiterrestrial, or terrestrial. Although habitual terrestriality is pervasive among the apes and African and Asian monkeys (catarrhines), it is largely absent among monkeys of the Americas (platyrrhines), as well as galagos, lemurs, and lorises (strepsirrhines), which are mostly arboreal. Numerous ecological drivers and species-specific factors are suggested to set the conditions for an evolutionary shift from arboreality to terrestriality, and current environmental conditions may provide analogous scenarios to those transitional periods.

Fruit availability has a complex relationship with fission-fusion dynamics in spider monkeys.

Understanding the ecological and social factors that influence group size is a major focus of primate behavioural ecology. Studies of species with fission-fusion social organizations have offered an insightful tool for understanding ecological drivers of group size as associations change over short temporal and spatial scales. Here we investigated how the fission-fusion dynamics of spider monkeys (Ateles geoffroyi) at Runaway Creek, Belize were affected by fruit availability.

Seasonal and sex differences in the fission-fusion dynamics of spider monkeys (Ateles geoffroyi yucatanensis) in Belize.

Spider monkeys (Ateles sp.) are characterized by high fission-fusion dynamics, meaning their social grouping pattern is fluid and consists of subgroups that vary in size, composition, and spatial cohesion over time. In this study, we quantify the fission-fusion dynamics of a group of spider monkeys at Runaway Creek Nature Reserve in Belize by measuring subgroup size, spatial cohesion, and stability using data spanning 5 years.