Sample collection and DNA extraction
In total, 14 samples were collected, including six (three males and three females) from Huangshan, five (three males and two females) from Guiyang City, and three (two males and one female) from Yongxing County. All individuals were healthy adults. Upon capture, the snakes were immediately placed in sterilized plastic collection boxes overnight to collect feces using sterile disposable gloves. The feces were collected in 2-mL collection tubes containing DNA preservation solution and placed in liquid nitrogen for rapid freezing, with subsequent preservation in a −80 °C refrigerator at the Yibin Key Laboratory of Zoological Diversity and Ecological Conservation, Yibin University (YBU). The snakes were released at the collection sites after obtaining fecal samples. Genomic DNA was extracted from the gut contents by a commercial company (Novogene, Beijing, China) utilizing a DNA extraction kit (Catalog number: DP328) following the provided instructions. The Institutional Animal Care and Use Committee at Yibin University (YBU2020007).