HOPE report


Study on Social behaviors of Wild Orangutans ; focusing on males


Date:2007/06/07 - 2007/08/17

We have continued the field research on wild orangutan in a research area which we newly settled around a tourist lodge in Danum Valley Conservation Area, Malaysia. About 4 year has passed since we set up this new research area. During the research from June to August 2007, I could track and observe 9 resident orangutans. Total observation time was 126 hours 19 minute (in 16 days). In addition, I conducted fallen fruits census and nest census per month. The amount of fruits increased at this time because of small mast fruiting season occurred on last July and August 2007 in this site. Especially, some orangutans gathered on the fruit tree of durian (BOMBACACEAE Durio zibethinus). We understand gradually that there are two individual groups in 2km2 around this site roughly. I observed for the first time that one Flange Male (we called King) came to other area, and he was feeding durian.

Flange Male eats durian

Research assistant and durian fruit

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