Gerard's Water Snake

Fascinating facts about the Gerard's Water Snake

• Gerarda prevostiana feeds almost exclusively on crabs, which it tears into bite-size pieces by pulling them through its coils, unlike most other snakes which swallow their prey whole.
• At 41 cm long (about 16 inches) with a 5 cm tail, this water snake has a glossy dark-olive coat with three outer rows of whitish scales.
• Gerarda prevostiana is found in coastal areas from western India (Mumbai) to the eastern Philippines, occurring in India (including the Andaman Islands), Sri Lanka, Bangladesh, Myanmar, Thailand, Peninsular Malaysia, Singapore, Cambodia, Indonesia (Borneo: Sarawak), and the Philippines (Luzon).

At a glance

About the Gerard's Water Snake

Gerarda prevostiana, the glossy marsh snake, is a sleek, dark-olive serpent that glides through mangrove-lined coastlines from Mumbai in western India to Luzon in the eastern Philippines. Its body, uniformly dark olive above, is accented by three outer rows of whitish scales, a stark white upper lip, and a dark-olive rostral, while the ventral surfaces and subcaudals are whitish with dark edges. Measuring about 41 cm (16 in) in total length, with a 5 cm (2 in) tail, this modest-sized snake bears a distinctive scalation: a frontal scale slightly longer than broad, a single preocular, two postoculars, temporals in a 1+2 arrangement, eight upper labials (the fourth entering the eye), and dorsal scales in 17 rows at mid-body. Its ventrals number 146–158, the anal plate is divided, and subcaudals number 31–34. By night, this terrestrial, nocturnal hunter slips silently among the roots of mangrove forests, where it employs a unique feeding strategy, rather than swallowing prey whole, it tears crabs into bite-sized pieces by pulling them through its coils, a behavior almost unheard of among snakes. This specialized diet of crabs, combined with its nocturnal, coastal lifestyle, makes Gerard’s water snake a vivid illustration of evolutionary adaptation to a niche that few other reptiles occupy, prompting the reader to wonder how such a seemingly simple creature has refined its hunting technique to such a precise degree…

More reptiles to discover

Browse Feravox