HOPE report


Overseas field research in Bali

Report:Jean-Baptist LECA

Date:2008/08/14 - 2008/08/28

From August 15th to 24th, I conducted a preliminary study of the stone handling (SH) behavior in the long-tailed macaques (Macaca fascicularis) living at the Sacred Monkey Forest Sanctuary, Ubud, Bali. This is the first systematic research on SH in long-tailed macaques, as a way to provide a broader cross-species comparison of the macaque SH tradition.

Data were collected in collaboration with Dr. M. A. Huffman and Doctoral candidate C. A. D. Nahallage from the Section of Social Systems Evolution, PRI. I used the exact same observation procedure as the one used to obtain SH data in Japanese and rhesus macaques. I conducted observations everyday from 9:00 to 17:00, collecting 15-min video-recorded focal samples and ad libitum video records on SH throughout the day, and instantaneous activity group scans every hour.

During the 125-hour observation period, we collected a total of 65 hours of video records, including 210 focals. Preliminary analyses reveal that this troop of long-tailed macaques show a high diversity and complexity in the form of SH, with 32 SH patterns exhibited, among which two patterns have never been reported in Japanese and rhesus macaques. The frequency and prevalence of SH was quite high, with all age and sex classes displaying the behavior.

From August 25th to 27th, we visited four additional macaque field sites in Bali, in contemplation of a future inter-troop comparative study of SH. On the morning of August 27th, we were invited to participate in a seminar organized by our Balinese colleagues from Udayana University's Primate Research Center, Denpasar, and I gave a talk entitled "Stone handling in Japanese macaques: different approaches to an exaptive behavioral tradition", reviewing my post-doctoral research conducted in Japan. I left Bali on August 28th and arrived in Nagoya on August 29th.

JB Leca filming long-tailed macaques handling stones

Seminar at Udayana University

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