Doctoral Dissertation Research: The role of thermoregulation in the obstetrical dilemma

在人类分娩中，婴儿与产道非常紧密地结合在一起，人类学家感兴趣的是，是什么进化压力导致了女性骨盆的大小和形状，这可能导致难产。这个项目将测试体温调节假说，该假说表明，人类骨盆的宽度受到保持窄小身体的需要的限制，而窄小的身体善于保持凉爽。人类祖先在温暖的气候中进化，从事艰苦的活动，而狭小的身体有助于调节温度。将收集有关骨盆尺寸的骨骼数据和来自活人的体温调节数据，以解决体温调节假说。这些数据还可能为预测有难产风险的女性以及防止娱乐和职业运动员过热提供信息。此外，该项目将支持对两名女本科生进行STEM培训，这些学生来自科学方面代表性不足的群体。该项目的成果将在当地高中和美国自然历史博物馆与普通公众分享。传统的解释是，两足动物移动时，狭窄的骨盆更有效率。传统的解释是，为什么现代人类女性的产道没有扩张以使分娩更容易。然而，体温调节假说一直被认为是一种相互竞争的假说，该假说认为在体力活动中，狭窄的骨盆有助于体温调节。这项研究将调查体温调节在限制产道进化中的潜在作用。研究人员假设，在现代人的体力活动中，狭窄的骨盆有助于体温调节，臀部宽度与产道面积相关，直立人是一种窄体、热适应的分类群。研究人员将收集跑步者的体温调节数据，以确定狭窄的骨盆是否在运动时具有体温调节优势；使用来自不同生态地理的种群创建的三维扫描仪测量女性骨盆尺寸；并重建KNM-WT 15000 H.Eecectus骨盆，这是有争议的，因为最初的重建提供了智人进化之前骨盆狭窄的唯一证据。这些数据将有助于更广泛地理解阻碍分娩背后的进化原因。

In human childbirth, the baby fits very tightly in the birth canal, and anthropologists are interested in understanding what evolutionary pressures may have led to a female pelvic size and shape that can contribute to difficult childbirth. This project will test the thermoregulation hypothesis, which suggests that the width of the human pelvis is limited by the need to maintain a narrow body that is good at staying cool. Human ancestors evolved in warm climates and engaged in strenuous activities, and a narrow body aids in temperature regulation. Skeletal data on pelvic dimensions and temperature regulation data from living people will be collected to address the thermoregulation hypothesis. These data may also be informative for predicting women at risk of obstructed labor and for preventing overheating in recreational and professional athletes. Additionally, this project will support STEM training for two female undergraduate students from groups underrepresented in science. Project results will be shared in local high schools and with the general public at the American Museum of Natural History.The traditional explanation for the "obstetrical dilemma," which asks why the modern human female birth canal has not expanded to make birth easier, is that a narrow pelvis is more efficient during bipedal locomotion. However, the thermoregulation hypothesis, which suggests that a narrow pelvis aids in thermoregulation during physical activity, has been discussed as a competing hypothesis. This research will investigate the potential role of thermoregulation in constraining the evolution of the birth canal. The investigators hypothesize that a narrow pelvis aids in thermoregulation in modern humans during physical activity, that hip breadth is correlated with the area of the birth canal, and that Homo erectus was a narrow-bodied, heat-adapted taxon. The investigators will collect thermoregulation data from runners to determine if a narrow pelvis bestows thermoregulatory advantages during exercise; measure female pelvic dimensions using three-dimensional scans created from eco-geographically varied populations; and reconstruct the KNM-WT 15000 H. erectus pelvis, which is controversial because the original reconstruction provides the only evidence of a hominin with a narrow pelvis prior to the evolution of Homo sapiens. These data will contribute to a broader understanding of the evolutionary reasons behind obstructed labor.