Racing Time: Physiological Rates and Metabolic Scaling in Marine Mammals
Racing Time: Physiological Rates and Metabolic Scaling in Marine Mammals
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比赛时间：海洋哺乳动物的生理速率和代谢规模
DOI：
10.1093/icb/icac054
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发表时间：
2022
影响因子：
2.6
通讯作者：
Williams, Terrie M
中科院分区：
文献类型：
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作者：
Williams, Terrie M
从1000-6000万年前开始，古代哺乳动物再次入侵海洋，引发了整个进化时期最显着的新陈代谢转变之一。海洋生物的一个后果，特别是在较冷的水域，水獭、鳍脚类和鲸目动物的静息代谢率(RMR)比体重相似的陆地哺乳动物的预测水平增加了1.4-2.9倍。值得注意的是，最大的代谢升高发生在最小的海洋哺乳动物，这表明潜在的热引起机制。叠加在这些休息成本之上的是运动的新陈代谢需求。统称为田间代谢率(FMR)，无论运动方式、物种、觅食模式、栖息地或地理位置如何，这种活跃成本始终接近个体静息率的三倍。在野生非繁殖哺乳动物中，陆地和海洋物种的FMR/RMR比率平均为2.6-2.8，后者在相对较高的食物摄入量的支持下保持了较大的绝对每日代谢率。有趣的是，人类耐力运动员习惯性(多天)、持续最大能量消耗的极限平均是静息代谢水平的3.0倍，环法自行车赛运动员是一个明显的例外。重要的是，运动员和野生哺乳动物似乎都受到了类似的限制；也就是说，在一天内处理足够的卡路里来支持非凡的新陈代谢表现的能力。
Reinvasion of the oceans beginning 10–60 million years ago by ancient mammals instigated one of the most remarkable metabolic transitions across evolutionary time. A consequence of marine living, especially in colder waters, has been a 1.4–2.9-fold increase in resting metabolic rate (RMR) for otters, pinnipeds, and cetaceans over predicted levels for terrestrial mammals of similar body mass. Notably, the greatest metabolic elevation occurred in the smallest marine mammals, suggesting an underlying thermal causative mechanism. Superimposed on these resting costs are the metabolic demands of locomotion. Collectively termed the field metabolic rate (FMR), such active costs consistently approach three times the resting rates of individuals regardless of locomotor style, species, foraging patterns, habitat, or geographic location. In wild non-reproducing mammals, the FMR/RMR ratio averages 2.6–2.8 for both terrestrial and marine species, with the latter group maintaining larger absolute daily metabolic rates supported by comparatively higher food ingestion rates. Interestingly, the limit for habitual (multi-day), sustained maximal energy expenditure in human endurance athletes averages <3.0 times resting metabolic levels, with a notable exception in Tour de France cyclists. Importantly, both athletes and wild mammals seem similarly constrained; that is, by the ability to process enough calories in a day to support exceptional metabolic performance.