Yellow-bellied Puffface Water Snake
Gerarda prevostiana • Order: Squamata; Suborder: Serpentes; Family: Homalopsidae; Genus: Gerarda; Species: G. prevostiana
Found along the coastal regions of South and Southeast Asia, including India (western and eastern coasts), Sri Lanka, Myanmar, Thailand, West Malaysia, Singapore, and parts of Indonesia (Sumatra, Bangka).
Look up Yellow-bellied Puffface Water Snake in the Snake Encyclopedia →Venomous Status
Mildly venomous - Opisthoglyphous (rear-fanged)
Danger Level
Low Risk - Harmless to humans. Bites may cause minor localized swelling or itching but no systemic poisoning. Their small size and docile nature make them very low risk.
Family
Order: Squamata; Suborder: Serpentes; Family: Homalopsidae; Genus: Gerarda; Species: G. prevostiana
Conservation
Least Concern (IUCN), though local populations are threatened by the destruction of mangrove ecosystems and coastal development.
Physical Description
Features a distinct 'puff-faced' appearance due to thickened labial scales. The dorsal color is dark olive, grey, or blackish with faint yellowish speckling or mottling. The underside (ventral) is yellow or cream. It has small eyes with vertical pupils and smooth scales.
Size & Dimensions
Typical adult length ranges from 30 to 50 cm; the specimen in the image appears to be an adult or sub-adult fitting this range. Maximum recorded length is approximately 60 cm.
Habitat
Strictly associated with coastal mangroves, tidal rivers, mudflats, and estuaries. It is a brackish water specialist that hides in crab burrows and under mangal debris during low tide.
Behavior & Temperament
Primarily nocturnal and crepuscular. It is a slow-moving, docile snake that rarely attempts to bite humans. It is highly specialized for navigating the slippery mud of mangrove environments.
Diet & Feeding
A extreme dietary specialist feeding almost exclusively on freshly molted (soft-shell) crabs. It uses its body to pin the crab and may even disarticulate limbs to consume the soft interior.
Reproduction
Viviparous (gives birth to live young). Litter sizes are small, typically ranging from 3 to 5 neonates, born during the monsoon seasons when prey is abundant.
Venom Profile
Mildly cytotoxic and neurotoxic properties adapted specifically for immobilizing crustacean prey; not medically significant to humans.
Look-alikes
Often confused with the Dog-faced Water Snake (Cerberus schneiderii), which has heavily keeled scales and a more robust head, or the Glossy Marsh Snake (Gerarda prevostiana's close relative Fordonia leucobalia).
Conservation Status
Least Concern (IUCN), though local populations are threatened by the destruction of mangrove ecosystems and coastal development.
Cultural Significance
Ecologically vital as a specialized predator in mangrove ecosystems, helping to regulate crab populations. It is often a key biological indicator of mangrove health.
Notable Features
Equipped with unique behavioral adaptations to feed on crabs that are larger than its head by waiting for them to molt or by tearing pieces off—a rare behavior among snakes which usually swallow prey whole.