Department of Anthropology, University of Zurich, Zurich, Switzerland.
Research Centre in Evolutionary Anthropology and Palaeoecology, Liverpool John Moores University, Liverpool, United Kingdom.
Am J Primatol. 2019 Aug;81(8):e23035. doi: 10.1002/ajp.23035. Epub 2019 Jul 18.
Although it is generally assumed that among mammals and within mammal groups, those species that rely on diets consisting of greater amounts of plant fiber have larger gastrointestinal tracts (GIT), statistical evidence for this simple claim is largely lacking. We compiled a dataset on the length of the small intestine, caecum, and colon in 42 strepsirrhine, platyrrhine, and catarrhine primate species, using specimens with known body mass (BM). We tested the scaling of intestine length with BM, and whether dietary proxies (percentage of leaves and a diet quality index) were significant covariates in these scaling relationships, using two sets of models: one that did not account for the phylogenetic structure of the data, and one that did. Intestine length mainly scaled geometrically at exponents that included 0.33 in the confidence interval; Strepsirrhini exhibited particularly long caeca, while those of Catarrhini were comparatively short. Diet proxies were only significant for the colon and the total large intestine (but not for the small intestine or the caecum), and only in conventional statistics (but not when accounting for phylogeny), indicating the pattern occurred across but not within clades. Compared to terrestrial Carnivora, primates have similar small intestine lengths, but longer large intestines. The data on intestine lengths presented here corroborate recent results on GIT complexity, suggesting that diet, as currently described, does not exhaustively explain GIT anatomy within primate clades.
虽然人们普遍认为，在哺乳动物中，以及在哺乳动物群体内，那些依赖于大量植物纤维的饮食的物种，其胃肠道（GIT）较大，但这一简单说法的统计证据在很大程度上是缺乏的。我们编译了一个关于 42 种灵长类动物的小肠、盲肠和结肠长度的数据，这些动物的样本都具有已知的体重（BM）。我们使用了两组模型来测试肠道长度与 BM 的比例关系，以及饮食指标（叶片百分比和饮食质量指数）是否是这些比例关系中的重要协变量：一组模型不考虑数据的系统发育结构，另一组则考虑。肠道长度主要以包括 0.33 的几何指数进行缩放；懒猴类具有特别长的盲肠，而猫猴类的盲肠则相对较短。饮食指标仅对结肠和整个大肠（而不是小肠或盲肠）有意义，而且仅在常规统计学中（而不是在考虑系统发育时）有意义，这表明这种模式在整个进化枝中发生，而不是在进化枝内发生。与陆地食肉目动物相比，灵长类动物具有相似的小肠长度，但大肠较长。这里提供的肠道长度数据与最近关于 GIT 复杂性的结果相吻合，表明目前所描述的饮食并不能完全解释灵长类动物进化枝内的 GIT 解剖结构。
