Impacts of dietary modifications on the behaviour of captive western lowland gorillas (Gorilla gorilla gorilla).

Abstract

Behavioural profiles of captive and wild Gorilla gorilla gorilla have been shown to differ greatly, with captive gorillas moving and foraging much less than their wild counterparts and often experiencing high levels of obesity and cardiovascular disease.  Captive gorillas are typically fed an energy dense diet and housed in relatively small enclosures compared to wild gorillas that forage for large quantities of fibrous fruits and foliage over expansive home ranges.  These differences could be one of the leading factors in behavioural and health problems observed among captive gorillas.  This study examined behavioural profiles of captive gorillas fed experimental diets more nutritionally similar in both nutrient content and volume to those seen in the wild, particularly with the addition of woody browse and tamarind seed.  We predicted that when gorillas ate the experimental diets, they would display behavioural patterns more similar to their wild counterparts.  We found that feeding woody browses led to a reduction in coprophagy and regurgitation/reingestion (R/R) behaviours, but the addition of tamarind seed led to increased rates of coprophagy. These findings could be an important addition to management strategies in improving health and well-being among captive gorillas.