Energetic Competition Between Neandertals and Anatomically Modern Humans
Energetic Competition Between Neandertals and Anatomically Modern Humans
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尼安德特人与解剖学上的现代人类之间的激烈竞争
DOI：
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发表时间：
2009
期刊：
影响因子：
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通讯作者：
E. Churchill
中科院分区：
文献类型：
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作者：
A. Froehle;E. Churchill
气候对能量消耗的影响，包括气候对人体代谢生理的影响以及不同环境条件下生存所需体力活动水平的变化，一直是大量研究的焦点。总的来说，这项工作表明，生活在寒冷气候下的人类采集者往往比生活在温暖气候下的人类采集者有更高的能量消耗，无论是在维持能量需求（基础代谢率，BMR）还是获取资源所花费的能量方面。最近，几位作者将这些发现应用于化石记录，结果表明尼安德特人可能具有非常高的每日能量消耗（DEE），作为他们对寒冷气候下生活的调节和生存挑战的适应性反应的一部分。这些研究表明，解剖学上的现代人类的能量需求远低于欧洲的尼安德特人，因此比欧洲的尼安德特人具有竞争优势。然而，对于在寒冷气候下的解剖学上的现代人类来说，DEE 的估计并不存在，这就引出了一个问题：他们是否可能需要同样大量的能量才能在冰川欧洲生存。在这里，我们使用一种新方法对气候对尼安德特人和解剖学上的现代人类能量消耗的影响进行了探索性分析。该方法使用年平均气温以及体型、性别和年龄来预测基础代谢率，从而直接纳入气候对代谢生理学的影响。我们使用这种方法计算了尼安德特人和更新世现代人类样本中的 BMR，并根据氧同位素第三阶段项目提供的数据获得了化石地点的古平均年温度值。然后，我们使用基于生活在不同环境中的现有人类觅食者的气候特定体力活动水平 (PAL) 值，根据这些 BMR 值估算 DEE。我们的模型表明，在相似的气候条件下，尼安德特人比解剖学上的现代人类有更高的能量需求，每天大约 100-350 kcal，这证实了之前使用不同方法进行的研究结果。这种差异在很大程度上是由于尼安德特人的体重较大，这可能主要与解剖学上的现代人类相比肌肉质量比例较高有关。尼安德特人的肌肉发达，为他们提供了更强的体温调节能力，可能起到了隔热作用，也可能是与大型哺乳动物猎物近距离接触的生存策略的一部分。如果尼安德特人更大的肌肉质量可以达到这些目的，那么现代人类必须使用其他方法来处理绝缘和生存问题，以维持较小质量的身体。考古学证据与这种解释相一致，表明解剖学上的现代人类可能将改进的自我隔离方法以及更广泛的生存技术带到了欧洲。成人较低的能量需求可能为现代人类提供了生殖优势，表现为减少出生间隔、提高生存率或两者兼而有之。这可能会转化为相对于尼安德特人的竞争优势，尼安德特人的能源需求更高，因此更难满足。
The effects of climate on energy expenditure, which include climatic influences on human metabolic physiology and variation in the level of physical activity required for subsistence under different environmental conditions, have been the focus of a considerable amount of research. In general, this work shows that human foragers in habiting colder climates tend to have higher energy expenditure than those in warmer climates, both in terms of maintenance energy needs (basal metabolic rate, or BMR) and the amount of energy spent obtaining resources. Recently, several authors have applied these findings to the fossil record, with results that indicate that Neandertals would likely have had very high daily energy expenditure (DEE) as part of their adaptive response to the ther moregulatory and subsistence challenges of life in cold climates. These studies imply that anatomically modern humans would have had substantially lower energy requirements than, and thus a competitive advantage over, Neandertals in Europe. Estimates of DEE do not exist for anatomically modern humans in cold climates, however, begging the question of whether they might have required similarly high amounts of energy to survive in glacial Europe. Here we present an exploratory analysis of climatic effects on energy expenditure in Neandertals and anatomically modern humans, using a new method. This method uses mean annual temperature along with body size, sex and age to predict BMR, thereby directly incorporating the effects of climate on metabolic physiology. We used this method to calculate BMR in a sample of Neandertals and Pleistocene modern humans, obtaining paleo-mean annual temperature values for fossil sites from data available from the Oxygen Isotope Stage 3 Project. We then estimated DEE from these BMR values, using climate-specific physical activity level (PAL) values based on extant human foragers living in different environments. Our model suggests that Neandertals would have had substantially higher energy needs than anatomically modern humans in similar climates, on the order of 100–350 kcal per day, which corroborates the results of previous studies using different methods. This difference is in large part due to greater body mass in Neandertals, which may have related mainly to a higher proportion of muscle mass compared to anatomically modern humans. Great er muscularity in Neandertals would have provided them with greater thermoregulatory capability, may have served as insulation, and was also probably part of a subsistence strategy of close-range encounters with large mammalian prey. If greater muscle mass served these ends in Neandertals, modern humans must have used other means of dealing with insulation and subsistence in order to maintain less-massive bodies. There is archaeologi cal evidence consistent with this interpretation, suggesting that anatomically modern humans may have brought with them into Europe improved methods of insulating themselves, as well as broadened subsistence techniques. Lower adult energy needs could have provided modern humans with reproductive advantages in the form of re duced birth spacing, greater survivorship, or both. This would likely translate into a competitive advantage over Neandertals who had higher, and thus harder to meet, energy demands.