Reproductive biology of the Indo-Chinese ratsnake Ptyas korros (Colubridae) with implications for harvest sustainability

Context Reflecting their large body sizes, wide geographic distribution and abundance in anthropogenically disturbed southeast Asian habitats, Indo-Chinese ratsnakes (Ptyas korros) are heavily exploited for skins, meat, and traditional medicine. Aims We aimed to quantify sexual dimorphism and reproductive biology of Ptyas korros to broaden our knowledge of population abundance in West Java, Indonesia. Methods We measured and dissected 817 snakes at six processing facilities near Cirebon, West Java. Key results Males outnumbered females among the harvested sample except in January, and >80% of specimens were adults. Males matured at smaller sizes than females, but attained larger maximum sizes and were heavier-bodied than females of the same snout–vent length. Relative tail lengths did not differ between the sexes. Mean fat-body sizes and gonadal volumes varied among seasons, but egg-laying occurred in most months of the year. Clutch size range was 1–14 eggs (mean = 7.12), and increased with maternal body size. Conclusions Early maturation, frequent and relatively aseasonal reproduction, medium-to-large clutch sizes, and broad diets contribute to this species’ abundance in disturbed agroecosystems of West Java, enabling these snakes to persist despite heavy harvesting pressure. Implications Our data strongly suggest that offtake of this species in Java is sustainable.