British Antarctic Survey, High Cross, Madingley Road, Cambridge CB3 0ET, UK.
Am Nat. 2013 Sep;182(3):283-97. doi: 10.1086/671259. Epub 2013 Jul 19.
The metabolic status of dinosaurs has long been debated but remains unresolved as no consistent picture has emerged from a range of anatomical and isotopic evidence. Quantitative analysis of dinosaur energetics, based on general principles applicable to all vertebrates, shows that many features of dinosaur lifestyle are compatible with a physiology similar to that of extant lizards, scaled up to dinosaur body masses and temperatures. The analysis suggests that sufficient metabolic scope would have been available to support observed dinosaur growth rates and allow considerable locomotor activity, perhaps even migration. Since at least one dinosaur lineage evolved true endothermy, this study emphasizes there was no single dinosaur physiology. Many small theropods were insulated with feathers and appear to have been partial or full endotherms. Uninsulated small taxa, and all juveniles, presumably would have been ectothermic, with consequent diurnal and seasonal variations in body temperature. In larger taxa, inertial homeothermy would have resulted in warm and stable body temperatures but with a basal metabolism significantly below that of extant mammals or birds of the same size. It would appear that dinosaurs exhibited a range of metabolic levels to match the broad spectrum of ecological niches they occupied.
恐龙的新陈代谢状态一直存在争议，但由于各种解剖学和同位素证据都没有形成一致的画面，因此这个问题仍未得到解决。基于适用于所有脊椎动物的一般原理，对恐龙能量学进行的定量分析表明，恐龙生活方式的许多特征与现代蜥蜴的生理学相似，只是体型和体温有所放大。该分析表明，有足够的代谢范围来支持观察到的恐龙生长速度，并允许相当大的运动活动，甚至可能是迁徙。由于至少有一种恐龙进化出了真正的温血动物，因此这项研究强调，恐龙的生理学并非单一的。许多小型兽脚亚目恐龙都有羽毛作为隔热层，它们似乎是部分或完全的温血动物。没有隔热层的小型恐龙类群，以及所有的幼年恐龙，可能都是变温动物，因此体温会随着昼夜和季节的变化而变化。在较大的恐龙类群中，惯性体温调节会导致体温温暖且稳定，但基础代谢率明显低于同体型的现代哺乳动物或鸟类。似乎恐龙表现出一系列的代谢水平，以适应它们所占据的广泛生态位。
