We compared an early life stress indicator, linear enamel hypoplasia (LEH), in the canine teeth of two male orangutan (Pongo spp.) morphs. Flanged males have large bi-discoid cheek pads and a laryngeal throat pouch, and they exhibit either the same or higher levels of the stress hormone cortisol throughout development compared with unflanged males, which lack secondary sexual characteristics. Such “developmental arrest” is hypothesized to either reflect a response to experienced high stress (Hypothesis 1), or an adaptation to avoid elevated stress levels and/or having experienced lower stress levels (Hypothesis 2) during early life. As LEH defect depth has been shown to reflect the severity (i.e., intensity and/or duration) of early life stress events, we examined whether unflanged males have shallower LEH defects than flanged males.

中文翻译：

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有凸缘的猩猩与无凸缘的猩猩 (Pongo spp.) 的牙齿中出现更严重的应力标记

我们比较了两只雄性猩猩 ( Pongospp.) 变形。有凸缘的雄性有大的双盘状面颊垫和喉囊，与没有第二性征的无凸缘雄性相比，它们在整个发育过程中表现出相同或更高水平的压力激素皮质醇。假设这种“发育停滞”反映了对经历的高压力的反应（假设 1），或者是为了避免升高的压力水平和/或在早年经历过较低的压力水平（假设 2）的适应。由于 LEH 缺陷深度已被证明可以反映早期生活压力事件的严重程度（即强度和/或持续时间），我们检查了无凸缘雄性是否比有凸缘雄性具有更浅的 LEH 缺陷。