Monkey business: Inter-group differences in the object/food bartering practice in Balinese macaques (Macaca fascicularis) at the Uluwatu Temple, Indonesia
Bibliographic record
Abstract
While there is increasing evidence for the social transmission of behavioural innovations and intergroup behavioural variation in a wide range of nonhuman primate taxa, some behavioural domains (e.g., tool use) are far more represented than others (e.g., arbitrary social conventions) in the literature. Our study explores the ‘object/food bartering’ activity in the free-ranging long-tailed macaques, Macaca fascicularis, living around the Uluwatu temple, southern Bali (Indonesia). This practice occurs in two steps: after robbing temple visitors of non-edible objects, the monkeys use these objects as tokens, by returning them in exchange for specific food rewards. This spontaneous population-level activity is customary and enduring at Uluwatu, whereas it is very rare or absent at other macaque-tourism sites across the island. During a fourmonth study in 2010 at Uluwatu, we used the all-occurrence sampling technique to record 186 successful events of object-robbing, where 95 (51%) were followed by object/food bartering attempts. In line with the ‘needing-to-learn’ hypothesis, we found that older individuals were significantly more efficient at robbing valuable objects and more successful at exchanging them for food than younger individuals. We also found substantial differences in the frequency and form of the bartering practice (n = 95 events) among the four social groups constituting the Uluwatu population, with two groups (‘Temple’: 60% of the bartering events, ‘Tear’: 34%) being responsible for more frequent bartering events than the two other groups (‘Scarface’: 4%, ‘Nez’: 2%). We investigated the role of group-specific environmental and anthropic influences (food provisioning and degree of human presence) in such intergroup differences. Taken together, these preliminary results suggest that the bartering practice could be a local behavioural tradition in \nBalinese macaques.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.003 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".