Doctoral Dissertation: Exploring Bison-Based Human Subsistence on the Northern Great Plains: Dental Enamel Hypoplasia, Bison Paleoecology, and the Archaeological Record

在David Meltzer博士的指导下，Ryan Byerly将研究来自11500到100年前考古遗址的北部大平原野牛的牙釉质发育不全（DEH）形成。DEH是牙釉质的畸形，可能反映了史前野牛的季节状况。了解这一点对猎人最大化脂肪回报至关重要。脂肪是人体更好地消化肌肉蛋白质所必需的。没有足够的脂肪，兔子可能会饿死（吃太多瘦肉）。考古证据表明，在过去的5000年里，平原上的狩猎采集者为了避免兔子饿死，他们在野牛最肥的月份捕猎它们，并大量折断它们的骨头，为冬天储存骨髓。然而，很明显，最早的古印度野牛猎人并没有这样做，而是全年断断续续地捕猎，很少折断骨头获取骨髓。古印第安人对营养的需求是否与他们的后代不同，或者他们的饮食中是否补充了骨髓脂肪以外的营养？是不是早期的野牛一年到头都比它们的后代生活得更好？解决这些问题很困难，因为考古学家依靠现代野牛生态学的知识来了解野牛的古生态学。这种依赖是有问题的，因为在过去的11000年里，野牛为了适应不断变化的大平原环境而发生了显著的进化。因此，需要一个可靠的史前野牛健康指标来建立一个更有力的古生态记录，从而更好地解释平原狩猎采集者的狩猎和屠宰行为。本研究将DEH作为这样一个指标进行评价。虽然目前尚不清楚导致野牛DEH形成的具体原因，但据推测，季节性饮食、出生和断奶压力以及疾病可能是原因。为了更好地了解DEH发生的原因，并进一步评价其作为季节性健康指标的作用，本研究将通过牙内碳氧同位素分析分析DEH发生的时间，并探讨季节性饮食应激对DEH形成的贡献。由于野牛牙釉质以可预测的速度形成，因此测量观察到的DEH在牙齿表面的位置可以提供应力的时间轴。比较过去11000头野牛种群的这些时间线可能有助于阐明出生和断奶时间表或疾病发作的差异。同样，牙釉质增量的碳和氧同位素分析提供了饲料和水消耗情况的粗略时间表。因此，还将评估季节性饮食变化对DEH形成的贡献。如果成功，这些数据将提供史前野牛健康和生态的关键信息，这不仅有利于考古学家，也有利于现代野牛管理者和大平原保护工作。这项研究将通过强调考古和古生态工作的重要性来加强保护教育，以了解大平原上野牛的历史，它们作为关键物种的作用，并确保它们未来的生存。

Under the direction of Dr. David Meltzer, Ryan Byerly will investigate dental enamel hypoplasia (DEH) formation in Northern Great Plains bison from archaeological sites dating between 11,500 and 100 year ago. DEH is a deformity in tooth enamel that may reflect the seasonal condition of prehistoric bison. Understanding this would have been critical to hunters to maximize fat return. Fat is necessary in human to better digest muscle protein. Without sufficient fat rabbit starvation (eating too much lean meat) can occur. Archaeological evidence indicates that in the last 5,000 years Plains hunter-gatherers avoided rabbit starvation by hunting bison during their fattest months and intensively breaking bones for marrow to store for winter. However, it is apparent that the earliest Paleoindian bison hunters did not do this, but rather hunted episodically throughout the year and rarely broke bones for marrow. Did Paleoindians have different nutritional requirements than their descendents, or supplement their diets with nutrients other than marrow fat? Were early bison simply in better condition throughout the year than their descendants? Resolving these questions is difficult because archaeologists rely on knowledge of modern bison ecology to understand bison paleoecology. This reliance is problematic because bison have evolved significantly over the past 11,000 years in response to changing Great Plains environments. Thus, a reliable indicator of prehistoric bison health is needed to develop a stronger paleoecological record and thus also better account for the hunting and butchery behaviors of Plains hunter-gatherers. This research will evaluate DEH as such an indicator. Although it is unknown what specifically causes DEH formation in bison, it is hypothesized that seasonal diet, birthing and weaning stress, and disease are probable causes. To better understand the causes of DEH, and further appraise it as an indicator of seasonal health, this research will analyze DEH timing and explore the contribution of seasonal dietary stress to its formation through intra-tooth carbon and oxygen isotopic analysis. Since bison enamel forms at a predictable rate, measuring the location of observed DEH on tooth surfaces can provide a timeline of stress. Comparing these timelines in bison populations over the past 11,000 may help illuminate differences in birthing and weaning schedules or disease episodes. Likewise, carbon and oxygen isotope analysis of tooth enamel increments provides a rough timeline of the condition of forage and water consumed. The contribution of changing seasonal diets to DEH formation will therefore also be assessed. If successful, these data will provide critical information about prehistoric bison health and ecology that is beneficial not only to archaeologists, but also to modern bison managers and Great Plains conservation efforts. This research will serve to enhance conservation education by stressing the importance of archaeological and paleoecological work to understanding the history of bison on the Great Plains, their role as a keystone species, and ensuring their future survival.