More Than Just Kibbles: Keeper Familiarity and Food Can Affect Bonobo Behavior

SIMPLE SUMMARY: Food availability can affect animal welfare, but it is not the only factor in play. Caregivers also affect welfare, and this aspect may especially apply to bonobos, the great apes that (with chimpanzees) are closest to us. In a bonobo group (17 individuals; La Vallée des Singes, France), we video-recorded behaviors possibly expressing positive emotions (e.g., play) and negative emotions (e.g., aggression or displacement anxiety activities), requests (gestures) and affiliation (e.g., sociosexual interactions). Within a few minutes around food provisioning, we determined behavioral frequencies with more/less familiar keepers and with different food types (kibbles/fruits/vegetables) or no food. More familiar keepers—regardless of food—were linked to more sociosexual contacts, which are probably used to contain excitement (more familiar keepers are strongly associated with forthcoming food). More familiar keepers—when distributing fruits/vegetables—were linked to more gestures, probably used to request and catch fruit items first. Preferred food increased aggression, with no keeper effect, probably because a highly valued resource (kibbles, not catchable by hand) was at stake. Play did not vary possibly because it works over longer time windows. Bonobo welfare may be improved by considering more than just food and that great apes are more similar to humans than to other animals. ABSTRACT: The welfare of captive animals relies on numerous factors. Keepers can affect animals’ welfare and this could especially apply to emotionally and cognitively complex species, such as great apes. We collected video data over three months on 17 bonobos (La Vallée des Singes, France) and extracted five behaviours (play, aggression, anxiety, gestures, sociosexual interactions) —during two-minute slots—under three conditions: keeper-present/food-unavailable; keeper-present/food-available; keeper-absent/food-unavailable. We ran generalized linear models to investigate whether behavioral frequencies were affected by food presence/quality and keeper familiarity. Anxiety-related behaviors increased when the keeper was present and in absence of food, due to food expectation. Sociosexual interactions increased in presence of more familiar keepers and in absence of food, maybe to decrease the tension around food. Gestures increased in presence of more familiar keepers and with low-quality food, which was provided in large ‘catchable‘ pieces. Aggression levels increased with high-quality food with no effect of keeper. Play behavior was not affected by any variable. Hence, bonobos were affected not just by food but also by keeper features. Considering multiple variables in the ‘welfare equation’ can improve captive management and increase the well-being of bonobos, a species that is much closer to humans than to other non-human animals.