Bamboo feeding induces complex browsing activity and increases foraging time in zoo-kept Asian elephants (Elephas maximus)

Abstract

We evaluated the impact of feeding enrichment using bamboo on the activity budgets of zoo-kept Asian elephants (Elephas maximus). Four elephants (1 male and 3 females, aged 4 to 8 years at Kyoto City Zoo) were allocated to conventional feeding (CON, sudangrass hay at 2.5 kg fresh matter (FM)/head) and bamboo feeding (BAM, sudangrass hay replaced with bamboo at 4.5 kg FM/head) treatments. The behaviors were recorded during the day (9:30 am-3:30 pm) in the outdoor paddock by direct observation and during the night (3:30 pm-9:30 am) in the indoor pen by video cameras. During the day, the elephants in BAM showed a greater proportion of foraging than in CON due to increased feed amounts and time spent processing bamboo. Feeding elephants bamboo during the daytime did not affect their nighttime behavior. The elephants in both treatments spent 15.6-22.3% of their time stereotypically pacing at night, especially in the early morning. The results suggest that replacing hay with bamboo increases the feeding amount and induces complex browsing activity, increasing foraging time. Additionally, stereotypic pacing mostly occurred in the early morning when elephants had less opportunity to feed, suggesting that feeding enrichment should be implemented during this period.