Reproductive biology of the Javan Keelback watersnake Fowlea melanzosta (Natricinae, Colubridae)

Dissections of 427 Javan Keelbacks, Fowlea melanzosta (Gravenhorst, 1807) – 263 females, 164 males, collected by commercial hunters in the Cirebon area of West Java, Indonesia, provided information on sexual dimorphism and reproduction. The harvest consisted mostly of adult snakes, especially females, perhaps reflecting greater commercial value of larger animals. Females grew much larger than males but had shorter tails relative to body length. Clutch sizes ranged from 5 to 46 (mean = 21.0) and increased with maternal body size. Adult females produce a single clutch of eggs annually, prior to the onset of the rainy season, and likely remain with those eggs until hatching (based on behaviour of the closely related F. piscator in India). Testis volumes in adult males showed strong seasonal variation. The high fecundity and ecological flexibility (diverse diets, use of disturbed habitats) of this species is likely to buffer it against any population-level impact of commercial harvesting.