Case study: Visual barriers reduce pacing in captive tigers

Captive large felines are prone to abnormal repetitive behaviors like pacing, which are associated with welfare issues. Visual contact without the opportunity to engage in appropriate behavior is known to increase pacing. To better understand the relationship between pacing and conspecific visual contact, we investigated this effect by conducting a barrier experiment on a male-female pair of Sumatran tigers (Panthera tigris sumatrae) in Rotterdam Zoo, the Netherlands. The tigers were exposed to four consecutive housing treatments: (i) housed in the same enclosure (baseline), (ii) housed in separate enclosures with visual contact, (iii) housed in separate enclosures without visual contact, and (iv) housed in the same enclosure after the separation. We used focal and scan sampling to measure pacing and recorded the number of visitors. Moreover, we applied scan sampling to measure activity. Overall, our results indicate that the tigers paced significantly more when housed in separate enclosures with conspecific visual contact. Moreover, our results suggest that limiting visual contact between neighboring tigers can mitigate pacing. Implementing these findings in tiger husbandry and enclosure design has the potential to improve animal welfare zoo populations of large felines.