Development of sexual and socio-sexual behaviours in free-ranging juvenile male Japanese macaques, Macaca fuscata
Bibliographic record
Abstract
The emergence of conceptive and non-conceptive sexual behaviours in mature individuals can be traced back to immature socio-sexual behavioural patterns. We tested the ‘needing-to-learn hypothesis’ in the development of sexual behaviours in the immature male Japanese macaques of Arashiyama, Japan. This hypothesis holds that juvenility serves to provide young individuals with a period in which to practice adult male-like sexual and socio-sexual behaviours and partner choice. Our cross-sectional focal data on mounting behaviour and partner choice in juvenile males (1–3 years) supported most of our predictions: (1) as they became older and learnt more effective patterns of sexual solicitations, juvenile males performed more demonstrative solicitations and less non-demonstrative solicitations, (2) the frequency of mounts performed by juvenile males increased with age and converged on a frequency of mounts typical of adult males, (3) the frequency of mounts reflecting underachievement (i.e., improperly oriented mounts and single/no foot-clasp mounts) decreased as juvenile males became older, (4) the double foot-clasp mounting posture became gradually more common in juvenile males over time, while other mounting postures became less common and (5) from two to three years old, the frequency of males’ sexual mounts directed to adult females increased. Such timelines of gradual increase in the frequency of effective adult-like behavioural patterns and gradual decrease in the frequency of less effective immature behavioural patterns are consistent with the ‘needing-to-learn hypothesis’ emphasizing the role of age and practice in the progressive acquisition of adult-like sexual behaviour, mounting skills, and partner age choice during male juvenility.
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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 | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 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) | 0.001 | 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".