Species : Cerberus schneiderii
Maximum Size : up to 108 cm
The Dog-faced Water Snake
or Schneider's Bockadam, is a common, and often locally abundant inhabitant
of Southeast Asia's mangroves and mudflats. This species emerges in great
numbers at night during low tide to feed on fish and invertebrates.
The dorsal colour is
greyish brown, and the ventral surface brown with white patches or cream-coloured
and mottled. There is a black line from the eye to the neck, and its eyes
are located on top of the head, allowing it to maintain vision when
half-submerged in the mud. Though a mildly venomous, back-fanged species it
is generally not aggressive.
The species has other physical and behavioural adaptations to its ecological
niche, such as nostrils which can be closed by a valve-like structure to
exclude water, salt-secreting glands, and the ability to efficiently
'sidewind' across slippery mudflats.
Schneider's Bockadam occurs in coastal areas of Vietnam, Cambodia, Thailand, Peninsular
Malaysia, Singapore, the Philippines and the whole of Indonesia (excluding
Based on Murphy et al (2012), who revised the genus Cerberus, in
addition to C. schneiderii there are four other species in the genus,
three of which occur in Southeast Asia as follows :
- C. rynchops, the
Karoo Bockadam, which occurs along the coastline of Burma (Myanmar), as well
as Bangladesh, India and Sri Lanka.
- C. australis, the Australian Bockadam, which occurs in parts of
eastern Indonesia, as well as the southern coastline of New Guinea, and the
northern coastline of Australia.
- C. microlepis, the Lake Buhi Bockadam, which is a land-locked,
freshwater species confined to the Philippine island of Luzon.
The remaining species,
C. dunsoni, the Palau Bockadam, is endemic to the pacific island of
The term 'Dog-faced Water Snake' may apply to any of the five species of
Fig 1 : Full-grown specimen of Schneider's
Bockadam in the mangroves of Khatib
Fig 2 : Specimen emerging from a burrow on the mudflats of Sungei Buloh, Singapore.
Fig 3 : Typical posture when hunting for small fish.
Fig 4 : A successful catch being consumed by the banks of a mangrove inlet,
Fig 5 : The pale, worn out skin and opaque eye scale of this specimen
indicate it is ready to shed its old skin. Seen at Pasir Ris,
References : H2, H3
Murphy, John C; Voris, Harold K. & Karns,
Daryl R. 2012. The Dog-faced Water Snakes, A Revision of the Genus
Cerberus Cuvier, (Squamata, Serpentes, Homalopsidae), with the
Description of a New Species. Zootaxa 3484:1-34.