Sexual Signaling in Male Vervet Monkeys (Chlorocebus Pygerythrus); Influences of Hormones, Behaviour, and Parasitism on Scrotal and Penile Skin Colouration
Bibliographic record
Abstract
Male secondary sexual characteristics may convey information about the signaller. The red penis and blue scrotum of male vervet monkeys make them a good species to examine variation in signal expression. We quantified colour in vervets at Lake Nabugabo, Uganda from standardized photos. We hypothesized that inter- and intra-individual variation in the expression of the genital colour of males is influenced by parasites, dominance rank, age, androgens and glucocorticoids. Our results indicate that blue scrotal colour between males is predicted by rank and parasites, and red penis colour is predicted by age (or sexual maturity) and parasites. Within males, our findings indicate that short-term variation in blue scrotal colour characteristics and contrast are negatively correlated with measures of parasitism and red penis hue becomes redder (less pink) as males increase in rank. These findings support the Hamilton-Zuk hypothesis and suggest that vervet genitals are a badge of status symbol.
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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 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 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) | 0.002 | 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".