Karasov W H, Diamond J M
Science. 1985 Apr 12;228(4696):202-4. doi: 10.1126/science.3975638.
Little is known about the digestive adaptations that enable mammals to sustain metabolic rates an order of magnitude higher than those of reptiles. Comparison of several features of digestion in mammals and lizards of similar size eating the same diet revealed that mammals processed food ten times faster and with the same or greater extraction efficiency. Transport kinetics and rates of nutrient absorption normalized to the quantity of intestinal tissue were similar in these two classes of vertebrates. The main basis for faster absorption in mammals is their much greater intestinal surface area.
关于使哺乳动物能够维持比爬行动物高出一个数量级的代谢率的消化适应性，人们所知甚少。对食用相同食物的大小相似的哺乳动物和蜥蜴的几种消化特征进行比较后发现，哺乳动物处理食物的速度快十倍，且提取效率相同或更高。这两类脊椎动物的转运动力学和营养物质吸收速率（以肠道组织数量进行归一化）相似。哺乳动物吸收更快的主要原因是它们具有大得多的肠道表面积。
