Document Type


Date of Degree Completion

Spring 2022

Degree Name

Master of Science (MS)


Primate Behavior

Committee Chair

Jessica Mayhew

Second Committee Member

Jean-Baptiste Leca

Third Committee Member

Kara Gabriel


Long-tailed macaques (LTMs, Macaca fascicularis) have multiple stone handling (SH) patterns that vary in form and complexity across different populations, but little is known about the group of Balinese LTM’s motivation to wrap stones in the Monkey Forest of Ubud, Indonesia. This study focuses on whether the SH pattern, wrap (WRP), is an object play behavior with the potential of becoming a more functionally complex behavior (e.g., tool use). SH sequences were collected using all-occurrence and focal sampling and examined using the program Behavioral Observation Research Interactive Software (BORIS). In total, 322 minutes of footage were reviewed for both stones and edible items. The WRP pattern performed on stones had a higher relative frequency (9.0%) compared to edible items (2.3%). The same was true for the relative duration, with individuals wrapping stones (3.0%) longer compared to edible items (1.6%). Overall, Balinese LTMs used material items more frequently and for longer durations to wrap stones than edible items, and in addition, there was a significant positive correlation between the processing behavior cover and hold (CAH) and consumption behavior bite (BIT) for stones. Studying this particular SH pattern provides an opportunity to learn more about how certain behaviors might have evolved into more functional behaviors, which could help explain the underlying motivational processes for performing those behaviors.

Available for download on Thursday, June 20, 2024