CONCLUSIONS
The composition and abundance of gut microbiota in V. stejnegeri differed from those of other examined snake species. Notably, the gut bacteria of V. stejnegeri encompassed 47 phyla, 101 classes, 214 orders, 514 families, and 1 951 genera. The top four most abundant phyla were Proteobacteria, Bacteroidetes, Actinobacteria, and Firmicutes, respectively, while the four most abundant genera wereSalmonella , Citrobacter , Bacteroides , andYokenella , with S. enterica , a pathogenic intestinal bacterium, showing the highest relative abundance. The four most abundant CAZymes in the gut microbiota of V. stejnegeri were GT2, GT4, GH23, and GT51. Significant differences were observed in the PCoA and LEfSe analyses of the gut microbiota among the three populations, as well as in the composition and abundance of CAZymes. Our study indicated that these population differences in gut microbial composition and abundance were not related to genetic differentiation but may be associated with differences in altitude and habitat. We hypothesized that variations in Bacteroides contributed to differences in CAZyme composition and abundance among the three populations. Future research should expand the host range to further explore the relationship between more geographic populations and gut microbiota, and to analyze the specific functions of the gut microbiota in conjunction with gut contents.