English name: Puff-faced Water Snake (aka “Banded Swamp Snake”, “Linne’s Water Snake”)
Scientific name: Homalopsis buccata
Thai name: Ngu Hua-kra-lok, Ngu Leuamao
Description: To 137cm long. Robust, somewhat flattened body. Notable broad, brown head with dark eyestripes, a “V” marking on top of the head and an inverted “V” on the snout. Has keeled scales. Body is dark brown to black with narrow light bands that fade in old age. Underside is white to yellow with small black dots.
Similar Species: Bocourt’s Water Snake is thicker and darker with black markings interspersed with the brown.
Red-tailed Pipe Snake has a small, dark head, smooth scales, and a barred underbelly.
Jack’s Water Snake can only be distinguished by scale counts (see note on bottom of account) and range
Habitat: Rivers, lakes, ponds, swamps, rice paddies, drainage ditches, and any other lowland habitat with water, including brackish water. Can be found in the water or on the banks. During the day it hides in burrows and crab holes.
Contribution to the ecosystem: Puff-faced Water Snakes eat fish, crustaceans, and frogs. Juveniles of the species are eaten by larger snakes, large fish, monitors, and wading birds.
Danger to humans: Can bite, but rarely does so and is not dangerous to humans.
Conservation status and threats: Due to its broad distribution and ability to live in human-altered habitats, this snake is not considered at risk, though it is listed as Vulnerable in Singapore. It is becoming popular in the pet trade, but that has only had an effect on populations at the local level. In nearby countries similar species are declining due to massive collection for food, skins and crocodile feed.
Interesting facts: The constantly updated research into taxonomy can sometimes make snake names confusing. The Puff-faced Water Snake, Homalopsis buccata, was once considered to occupy a huge range in south and southeast Asia from Indonesia to Nepal. However, a number of scientists studying the species found that it was actually five different species that had been confused with each other. These species are now:
Homalopsis buccata: Found in Indonesia, Singapore, Malaysia, and south Thailand
Homalopsis mereljcoxi: Found in Thailand (including Bangkok), Cambodia, and Vietnam
Homalopsis nigroventrali: Found in the Mekong River Valley in Thailand, Cambodia, and possibly Vietnam
Homalopsis semizonata: Found in Myanmar and possibly western Thailand
Homalopsis hardwickii : Found in Nepal
The five species are difficult to distinguish unless you are an expert, and may require scale counts to tell them apart. More information on the species and the rest of the Asian Water Snakes can be found in A Checklist and Key to the Homalopsid Snakes (Reptilia, Squamata, Serpentes), with the Description of New Genera, by John Murphy and Harold Voris.
The IUCN Red List: Homalopsis buccata
A Checklist and Key to the Homalopsid Snakes
A Photographic Guide to Snakes and Other Reptiles of Peninsular Malaysia, Singapore and Thailand
A Field Guide to the Reptiles of South-East Asia
A Field Guide to the Snakes of South Vietnam