Endangered Childhoods -
Longitudinal Socio-emotional Development of Orphaned Bonobos
in the Context of Sanctuary-Based Conservation

Abstract

This thesis explores the socio-emotional development of orphaned bonobos in the context of maternal loss, sanctuary care, and long-term adaptation. It reviews the evidence from humans and non-human primates showing the importance of maternal support for primate development, shaping survival, social integration, and psychological resilience. In great apes such as chimpanzees and bonobos, mothers continue to provide protection and social opportunities well beyond infancy, shaping long-term fitness outcomes and socio-emotional development. By contrast, maternal loss can have lasting detrimental effects on physical, physiological and psychological levels such as growth, survival, fitness, stress physiology, emotion regulation, and social functioning.
Evidence suggests that rehabilitation upon maternal loss is possible in socially enriched, naturalistic environments such as accredited great ape sanctuaries. Most of the research on ape socio-emotional functioning, however, has been cross-sectional, providing just snapshots of behaviour at specific times without taking into consideration developmental trajectories over time that would be a relevant indicator of life outcomes.
To address this gap, the empirical study presented here draws on a decade of longitudinal observations of sanctuary-living bonobos, published in Royal Society Open Science. It investigates how rearing background, sex, and age predict variation in social tendencies and aggression risk across the life span. Results highlight the potential that ape sanctuaries like this can have by demonstrating that orphans exhibit decreased affiliative tendencies yet show social functioning that ranges within patterns of their mother-reared peers.
Given the importance of maternal support for great apes' physical and mental development, it is critical to better understand the developmental trajectories of the growing number of orphans entering sanctuaries as a result of habitat degradation and the bushmeat trade. These insights are not only scientifically significant but also practically urgent, informing the rehabilitation and long-term care of endangered apes.