More of the Same Makes a Difference: Comparative Anatomy and Molecular Makeup of Tenrec and Hedgehog Intestines

ABSTRACT The macroanatomy of the digestive tract is typically interpreted in relation to trophic biology, potentially overlooking other determinants of digestive system design. Here, we investigate how digestive tract morphology reflects the interaction between anatomy, molecular makeup, taxon‐specific physiology, and ecological context. We show that several taxa occupying similar trophic niches, tenrecs ( Setifer setosus and Echinops telfairi ), African hedgehogs ( Atelerix and Paraechinus spp.), and the European hedgehog ( Erinaceus europaeus ), have similar gastrointestinal morphology (a simple stomach and an intestinal tube of largely homogeneous diameter without a cecum) yet differ markedly in total intestinal length, mainly due to differences in small intestine length. S. setosus has a comparable relative length of the intestinal regions to E. europaeus , while Atelerix albiventris has a slightly elongated large intestine. Although S. setosus exhibits enhanced absorptive capacity at the microanatomical level, reflected in higher serosal surface area enlargement factors, its shorter absolute intestinal length constrains total absorptive surface. Thus, E. europaeus possesses approximately 2.5 times the absorptive surface of A. albiventris and five times that of S. setosus . We suggest that these differences are related to differences in metabolic intensity, namely, energetic turnover and food‐processing rates. This is determined by both the taxon‐specific (Afrotheria vs. Laurasiatheria) pace of life and the extrinsic challenges of seasonal habitats with periods of resource scarcity and abundance, during which reproduction and adipose reserve accretion for the next winter occur. This supports the view that digestive tract morphology is shaped by the interaction of dietary, ecological, and phylogeny‐related physiological constraints.