Anogenital distance (AGD) is positively correlated to fetal androgen exposure and developmental masculinization in mammals. Independent of overall body size, AGD shows a strong positive correlation with male fertility and in rodents, AGD is a good indicator of male competitive ability and is associated with female choice. We hypothesized that AGD will also predict male competitive ability in non-human primates. To test this, we measured AGD noninvasively with a parallel laser in a wild population of Angolan colobus monkeys (Colobus angolensis ruwenzorii) in Uganda and correlated to it to their social structure. C. angolensis ruwenzorii form a multilevel society with both one-male/multifemale units (OMUs) and multimale/multifemale units (MMUs). We compared AGD in males from five OMUs and six MMUs and related it to their fecal androgen metabolite concentrations, dominance rank and body size, and to the number of females in their unit. Males in OMUs had greater access to females, so were predicted to have longer AGDs, but this was not found. AGD also did not correlate overall with mean fecal androgen metabolites in MMUs. However, AGD was correlated with dominance rank in MMUs, demonstrating that higher-ranking males in these multimale units had longer AGDs. Body size did not show the same relationship with dominance rank, suggesting that male rank was not just a reflection of absolute male size. Our findings indicate that AGD predicts male competitive ability in this species and that it may be a useful correlate throughout the non-human primates. These results also support the idea that prenatal androgen exposure increases the likelihood of the expression of behaviors that maintain high dominance rank.

中文翻译：

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生殖器距离是衡量Rwenzori安哥拉疣猴中男性竞争能力的量度。

生殖器距离（AGD）与胎儿雄激素暴露和哺乳动物的发育男性化呈正相关。AGD不受总体体型的影响，与雄性育性密切相关，在啮齿动物中，AGD是雄性竞争能力的良好指标，与雌性选择有关。我们假设AGD还将预测非人类灵长类动物的男性竞争能力。为了测试这一点，我们在乌干达的安哥拉疣猴（Colobus angolensis ruwenzorii）的野生种群中用平行激光无创地测量了AGD，并将其与它们的社会结构相关联。C. angolensis ruwenzorii组成一个多级社会，既有一个男性/多个女性单位（OMU），也有一个多男性/多个女性单位（MMU）。我们比较了来自五个OMU和六个MMU的雄性中的AGD，并将其与粪便中雄激素代谢物的浓度，优势等级和体型以及其单位中的雌性数量相关。OMU中的男性比女性更易接近，因此被预测具有更长的AGD，但这并未发现。AGD也与MMUs的平均粪便雄激素代谢产物总体上不相关。但是，AGD与MMU中的主导地位相关，表明在这些多男性单位中，排名较高的男性具有更长的AGD。体型与主导地位并没有显示出相同的关系，这表明男性等级并不只是绝对男性规模的反映。我们的发现表明，AGD可以预测该物种的雄性竞争能力，并且在整个非人类灵长类动物中它可能是有用的关联。