Organizational and activational androgens, lemur social play, and the ontogeny of female dominance.
Level 5 - mechanism / opinion, no new human data
Animal research (non-human primate observational cohort study)
PubMed 31276664 · doi:10.1016/j.yhbeh.2019.07.002
What was done
Researchers tracked 24 ring-tailed lemurs (*Lemur catta*; 8 males, 16 females) longitudinally from infancy to early adulthood. They recorded social behavior (rough-and-tumble play, aggression) and measured serum androgen concentrations (testosterone and androstenedione). Prenatal androgen exposure was assessed from maternal serum collected during gestation. Due to infrequent infant blood draws, imputation methods were applied to link postnatal hormone measurements with behavioral observations.
What was found
The abstract does not provide exact numerical concentrations, effect sizes, or test statistics. Reported directional findings include: - Typical mammalian sex differences in circulating androgen concentrations were present in young lemurs. - No significant sex difference was observed in rough-and-tumble play. - Female, but not male, aggression increased starting at approximately 15 months of age (coinciding with female puberty). - Differentiated behaviors showed no association with postnatal (activational) hormone levels, but showed significant relationships with prenatal (organizational) testosterone and androstenedione, which differed by sex and behavior type.
Why it matters
This study indicates that female social dominance in ring-tailed lemurs is programmed by organizational prenatal androgens—including androstenedione—rather than driven by activational hormones in adulthood.
Limits
Small sample size (24 lemurs total, with only 8 males). The study involves a non-human primate model, limiting generalizability. Infant blood sampling was sparse, necessitating statistical imputation for postnatal hormone-behavior associations. Exact effect sizes, variances, and p-values are not reported in the abstract.
Cited by
- contradicts Males across species, including humans, have an innate, hardwired predisposition toward rough-and-tumble play.