Behavioral flexibility - the ability to adapt behavior to changing circumstances - is emerging as an important indicator of positive welfare states in both wild and captive animals.
Behavioral flexibility is now understood as both a consequence and a cause of good welfare. Animals in chronic stress have reduced cognitive flexibility - they become locked into narrow behavioral routines that served them in the past but are maladaptive to changing circumstances. This inflexibility compounds welfare problems, as animals cannot adjust their behavior to cope with novel challenges. Conversely, environments that support behavioral flexibility - with enrichment, choice, and controllability - produce animals with better stress regulation, more diverse behavioral repertoires and greater resilience. This insight is transforming how welfare is assessed: rather than simply measuring absence of negative behaviors, good welfare assessment now includes tests of cognitive and behavioral flexibility as positive indicators.