Validating and Applying a Qualitative Behavioral Assessment Tool Designed for Gorillas

Qualitative behavioral assessments (QBAs) are unique tools specifically designed to take a subjective whole-animal approach to measuring animal welfare. These tools access care staff expertise in evaluating subtle shifts in posture and affective states. This quick, survey-style assessment may include both positive (appetite, curiosity, cooperation) and negative (aggression, anxiety, irritability) welfare indicators and can be particularly helpful in detecting individual shifts across conditions. Multiple assessments over time may even be used to investigate individual personality, as personality is classically defined as behavioral patterns that are stable across time. Staff at the Detroit Zoo have been working on developing and validating a QBA tool specifically for gorillas (the Gorilla Behavioral Assessment Tool or GBAT) since 2016. At the time of this study, the Detroit Zoo housed three adult male gorillas that lived cohesively in a bachelor unit. The bachelor unit was typically housed together indoors for three nights, then individually in behind-the-scenes spaces on the fourth night. The original 2016 application focused on investigating these overnight housing conditions. Using the GBAT, the study concluded that the gorillas displayed more positive welfare indicators following nights when they had been housed together. In 2021, the CZAAWE team revisited the GBAT aiming to demonstrate the reliability and validity of the tool. We again investigated overnight housing conditions. This study found that the gorillas displayed increases in positive welfare indicators and decreases in negative welfare indicators after having been housed individually overnight. We concluded that the needs of the group had evolved over time, allowing us to shift our management protocols to maximize the welfare of the gorilla group. We also found preliminary validation for the GBAT against physiological measures and a high percentage of reliability between care staff who completed the GBAT. Since the 2016 and 2021 applications, the CZAAWE team has continued efforts to validate the GBAT multi-institutionally and spread applications of the GBAT across the zoo-housed gorilla population.

https://doi.org/10.1002/ajp.23443