Behavioural diversity — the range of different behaviours an animal performs — is an important welfare indicator that reflects environmental richness and psychological health.
Behavioural diversity assessment moves zoo welfare evaluation beyond simply checking for the absence of stereotypies to assessing whether animals are expressing a full range of natural behaviours. An animal that does not pace but spends 18 hours sleeping in one spot is not necessarily thriving. Comparing the proportion of time spent in different activities against wild counterparts reveals the extent to which captive conditions allow natural life. High-quality enrichment programs should measurably increase behavioural diversity — this is the metric by which their welfare value should be judged. Welfare-conscious zoos use ethograms and time-activity budgets as standard management tools.