Bears in zoo collections are highly prone to stereotypic pacing and other repetitive behaviors — preventing these through environmental complexity is a central welfare challenge.
Stereotypic behavior in bears is a long-established welfare indicator that has driven substantial improvements in zoo bear exhibit design over recent decades. However, stereotypy in bears that developed it early in life is often irreversible — the neural pathways become entrenched regardless of subsequent environmental improvements. Prevention through appropriate environments from the outset is therefore crucial. Modern bear exhibits attempt to provide foraging complexity across large, varied spaces with multiple den options, water features, and substrates for digging. Polar bears pose particular welfare challenges given their extreme natural range requirements and highly specialized ecology. Some welfare scientists question whether polar bears can be kept in adequate welfare conditions in any zoo environment.