The species account records live-bearing reproduction, using the term ovoviviparous. A verified Philippine litter-size range and reproductive calendar are not established here.
Literature documented · Existing checklist occurrence statement and distribution review
The original evidence level is retained.
A country listing cannot establish an island or a precise locality.
Taxonomic context
Gerarda prevostiana is retained in the atlas’s dated checklist under Homalopsidae. The authority is (EYDOUX & GERVAIS 1837). Earlier names and the original source notes are preserved below for comparison.
Literature documented · Checklist identity and nomenclatural trail
Checklist verified 2026-09-05; not a newly revised taxonomic backbone.
Historical names can cover different biological concepts; synonyms should not be used to transfer records automatically.
Across the archipelago
Where this species is recorded
PhilippinesN ↑
Documented islands: gold · island groups: dashed circles
Island-level records · not continuous habitat coverage. Dashed circles locate groups, not individual observations.
Philippine distribution
Documented places
1 named island / island group
Select an island to read its distribution record and sources. Uncoloured islands are not evidence of absence.
Distribution record & sources
India (coastal Maharashtra, N Kerala, Gujarat), S Myanmar (= Burma), Sri Lanka, Thailand ?, Philippines, S Cambodia,
Bangladesh ?; West Malaysia; Singapore, Indonesia (Borneo: Sarawak)
Type locality: “Manille” (= Manila, 14°37' N, 120°58' E, Luzon, Philippines)
The atlas records Gerarda prevostiana from these named Philippine areas: Luzon. These are literature areas rather than a continuous range boundary.
Mildly venomous · Effects not yet summarised in this atlas
Observe from a distance. Do not handle, corner or capture a snake to identify it. An incomplete venom account is not evidence that a species is safe to handle.
After a suspected snakebite, keep the person still and arrange urgent medical care. Avoid tight tourniquets, cutting, suction and unproven remedies. Do not wait to identify the snake before seeking help.
Gerard's Water Snake, Cat-eyed Water Snake, Glossy Marsh snake · Katzenaugen-Wassertrugnatter
Authority
(EYDOUX & GERVAIS 1837)
Year described
1837
Taxonomic status
Accepted species
Family
Homalopsidae
Genus
Gerarda
Species epithet
prevostiana
Persistent ID
PH-SERP-AEB1F00E22
Checklist checked
2026-09-05
Philippine occurrence
Status
Present
Confidence
Confirmed
Basis
2018 Philippine synopsis treatment plus current RDB listing
Islands named
Luzon
Range noteCountry/island text is not a range polygon or locality record.
Source distribution statement
India (coastal Maharashtra, N Kerala, Gujarat), S Myanmar (= Burma), Sri Lanka, Thailand ?, Philippines, S Cambodia,
Bangladesh ?; West Malaysia; Singapore, Indonesia (Borneo: Sarawak)
Type locality: “Manille” (= Manila, 14°37' N, 120°58' E, Luzon, Philippines)
Knowledge coverage
EndemismResearch pending
EcologyLiterature documented
VenomMildly venomous Effects not yet summarised in this atlasDetailed research: Research pending
History: The year of description of this species has been given as “1822”; we cannot find a paper by Eydoux & Gervais from that year, but another paper published in 1837 is available online.
Diet: mainly crabs. The Gerard's water snake tears its prey into bite-sized pieces, in contrast to most other snakes (Jayne et al. 2002).
Habitat: marshes, mangroves and tidal rivers in the costal areas, i.e. partially “marine”.
Mildly venomous.
Type species: Coluber (Homalopsis) prevostianus EYDOUX & GERVAIS 1837 is the type species of the genus Gerarda GRAY 1849.
References attached to this record
2026
The Reptile Database — species checklist, 17 June 2026
Gerarda prevostiana — The Reptile Database species account
Uetz, P.; Hallermann, J. et al. (editors)
Public species fields consulted for bounded biological summaries. Primary sources quoted within the database were not independently examined unless explicitly stated. The catalogue name may differ from the current source title.