Snakes of Ko Pha-ngan in the Surat Thani Province, Thailand.

BACKGROUND: Insular snake species are often under-assessed, rendering them vulnerable to habitat encroachment and other anthropogenic threats. The aim of this study was to compile a comprehensive checklist of snakes on Ko Pha-ngan, Thailand. Data were collected via transect surveys, drift line fence traps and opportunistic encounters from February 2021 to September 2023. NEW INFORMATION: Twenty-one snake species were detected across three main habitats (human settlement, human-disturbed forest and national park forest) with the highest species diversity observed in the Than Sadet - Ko Pha-ngan National Park protected areas (20 species). Lycodon capucinus, Chrysopelea ornata, Ahaetulla prasina and Boiga cyanea were the most abundant species detected during surveys. Thirteen species were detected in all three habitat types, indicating broad habitat tolerance amongst several taxa. Two species, Ptyas korros and Ophiophagus bungarus, are assessed as Near Threatened and Vulnerable, respectively, according to the IUCN Red List of Threatened Species. Finally, the island harbours one endemic species, Oligodon phangan. This study highlights the need for additional monitoring to better understand the dynamics of insular populations and to assess the ongoing impacts of tourism-driven development on species within finite island habitats.