Foraging enrichment affects behaviour and enclosure utilisation in captive male gelada Theropithecus gelada

Abstract

Enrichment devices are important tools to engage zoo-housed animals in species-specific natural behaviours, which is critical to ensure animal welfare. The gelada Theropithecus gelada has a unique graminivorous feeding ecology, yet there is minimal enrichment research on the species. A novel foraging enrichment device was evaluated in a bachelor group of captive geladas (n=6) at Wild Place Project, Bristol UK, with the aim of understanding both group and individual response. Particular focus was put on foraging behaviour, enclosure utilisation and nearest-neighbour relationships. Six identical cuboid plastic containers, with large holes on three of the sides and a frame containing grass on the fourth, were used. The devices held fruits, vegetables and hay. Observations were conducted under three conditions: baseline, experimental and a post-experimental baseline. The devices were introduced during the experimental phase. Time spent consuming provisioned food and foraging wild foliage was significantly greater during the experimental condition. The increase in foraging of wild foliage was attributed to appetitive foraging. The foraging activity budgets were considered similar to wild counterparts during the study period overall, but greater during device implementation. This trend was attributed to the captive geladas having more available time to forage than their wild counterparts. Enclosure utilisation was also significantly greater during device implementation. In summary, this enrichment device increased foraging and enclosure utilisation in a bachelor group of captive geladas and produced similar activity budgets to those of wild counterparts. Therefore, it can be considered effective in improving captive gelada welfare.