Native to Africa, giraffes are browsers and are known to forage for tree bark as well as leaves in captivity. However, their preference for tree bark remains unclear. Therefore, in this study, we investigated their preference through behavioral observations at the Kyoto city zoo. The study period was divided into the green leaf (May-August) and deciduous (October-February) seasons based on the availability of trees. The tree species given in this study were Japanese white oak, cherry blossom, locust tree, lace bark elm, bayberry, Japanese hackberry, and glossy privet that are available in Kyoto, Japan. The results showed that bark foraging on locust tree and lace bark elm was significantly high (P < 0.01), while that Japanese white oak and Japanese hackberry was significantly (P < 0.01) low. This indicates that giraffes have a preference for bark. The foraging scores/kg tended to increase for bark-foraging species (rs = 0.56 or 0.75, P < 0.01), suggesting that feeding giraffes with bark-preferred tree species may promote species-specific behaviors in giraffe foraging enrichment.

Elephants are highly social animals and group living is important for their welfare. To provide a singly-housed captive elephant with the opportunity to live in social environment, group formation was attempted at the Kyoto City Zoo. In this study, we investigated the process by which social relationships were formed between newly introduced and existing animals as well as the effects of the introduction of new animals on the behavior of the existing animal. In 2014, the Kyoto City Zoo accepted four juvenile elephants from Lao P.D.R. We introduced these four juvenile elephants to a female elephant named Mito (born in 1971) who had been living alone in captivity for more than 10 years. We set up four stages for group acclimation. The first stage was habituation over fences in their indoor compartments. The second stage was habituations over electric fences in their outdoor compartments. In the third stage, we removed the electric wires between the enclosures and allowed the elephants to make direct contact over the fence. After we observed affiliative behaviors over the fence, we proceeded with the fourth stage of acclimation: allowing the elephants to be in the same compartment. We collected the behavioral data during the fourth stage between January 2018 and June 2019 by directly observing their behaviors or analyzing video-recording data. Although aggressive behaviors were observed in the early research stages (Period 1), these behaviors decreased within 1 year (Period 2). However, the quality of relationships differed depending on the individuals. The comparisons of the behaviors between whether or not elephants lived together (group / solitary condition) revealed no differences in "standing" or "other" behaviors; however, the proportion of "moving" and "social" behaviors increased in the group condition. Additionally, the proportion of abnormal behavior during the daytime decreased in the group condition. These results suggest that even an animal who has been kept alone for a long time can establish social relationships with other animals when he/she is introduced to a social environment, and this change improves animal welfare.