English name: Jagor’s Water Snake (aka: “Bangkok Mud Snake”)
Scientific name: Enhydris jagorii
Thai name: Ngu Sai-rung Lai Kwan
Description: To 68cm long. A short, thick snake. Head is short and rounded. Body is grayish-brown to dark brown with black blotches in a line down the sides. Underbelly is pale.
Similar Species: Chanard’s Mud Snake has a pale line below a row of small dark spots rather than larger dark blotches.
Jack’s Water Snake is lighter in color with a light barred pattern on body and dark mask on the face.
Bocourt’s Water Snake is much larger and has narrow yellow banding on black/brown background coloration.
Mekong Mud Snake has light lines along its sides and much smaller dark blotches.
Tay Minh Water Snake is similar to Jagor’s Water Snake, but is only found in the Mekong Delta.
Habitat: Found in floodplains, freshwater swamps and shallow marshes, including artificial wetlands and rice paddies.
Place in the ecosystem: Studies suggest that it feeds entirely on fish. Is eaten by larger snakes, large fish, monitors, and wading birds.
Danger to humans: Is an aggressive rear-fanged species and will bite when threatened but is not dangerous to humans.
Conservation status and threats: This species is only known from Thailand’s Central Plain, and in fact only one population is currently known to persist. It is locally abundant there, but human encroachment and the possible draining or pollution of its wetlands are a threat to its current habitat and thus its continued existence. Fishing with gill nets also kills a large number of the snakes. Protection of the snakes in this wetland may be critical to keep the species from extinction.
Interesting facts: References to the current distribution of Jagor’s Water Snake vary widely. Some sources state that it is only found in a single location in Thailand’s Central Plain, others state that it is found broadly in the Central Plain and Southeastern Basin, and still others state that it is a wide-ranging species that can be found in most of Thailand and beyond. Why the discrepancy? It’s likely due to taxonomic confusion. New species are discovered every year in Thailand, and often what was previously thought to a be a single species turns out to be 2, 3, or even 10 or more different species. At the same time, different species discovered in different areas sometimes turn out to have been the same species all along. As these things get sorted out, different references will update their records at different times (or sometimes even refuse to accept the same explanation), and thus such discrepancies arise.
In this case, the problem is likely that a species called the Tay Minh Water Snake is extremely similar to Jagor’s Water Snake but found in other areas, primarily the Mekong River drainage. Jagor’s Water Snake has also been confused with Chanard’s Mud Snake, another species that was once local to Bangkok.
Diet, female reproduction and conservation of Jagor’s water snake, Enhydris jagorii in Bung Ka Loh wetland
A New Thai Enhydris
IUCN Redlist: Enhydris jagorii
IUCN Redlist: Enhydris subtaeniata
Reptile Database: Enhydris jagorii
John C. Murphy, personal communication
Michael Cota, personal communication
A Photographic Guide to Snakes and Other Reptiles of Peninsular Malaysia, Singapore and Thailand
A Field Guide to the Reptiles of South-East Asia
Snakes of Thailand and their Husbandry