Reptilia · Squamata
Cerberus rynchopsSchneider, 1799
New Guinea bockadam
Photograph by Ronith Urs, CC BY, via iNaturalist
A water-living, active by day or night, meat-eating snake from the Oriental region, reaching 127 cm nose to tail.
Also called Dog-faced Water Snake, South Asian Bockadam.
Reptilia › Squamata › Homalopsidae › Cerberus
- Grows to
- 1270mm
- greatest recorded
- Eats
- Carnivorous
- Active
- Cathemeral
- Lives
- Aquatic
Longer than 95% of all species in Homalopsidae anyone has measured.
The bar is the rank itself: its length is the share of the family this animal exceeds. The chart below is the family’s real spread, on a logarithmic scale because body length here runs from 128 to 1,400 mm. The solid rule is this animal. Every bar is a count of real species, and nothing on this figure is estimated.
What is known
34 sourced facts, each taken from a named scientific dataset. How to read these.
Cited from a dataset unless a row is marked otherwise.
Two of these figures disagree
Lowest it lives (above sea level) is given as 19, and Highest it lives (above sea level) as 10 — but the lowest place it is found cannot be above the highest. They come from different sources and both are shown exactly as those sources give them.
Standing in the world
- Still living
- Extant
- Conservation status
- Least Concern
- Status assessed · the year the Red List last looked
- 2009
The animal itself
- Limbs
- None
- Pupil
- Vertical slit
- Fangs
- At the back of the mouth
Size
- Length snout to vent · greatest recorded
- 756mm2 ft 6 in
- Length snout to vent · adult female mean
- 587mm23 in
- Length nose to tail · greatest recorded
- 1270mm4 ft 2 in
- Female length · mean, nose to tail
- 721.5mm2 ft 4 in
- Body mass · greatestcomputed
- 1582.9g3.5 lb
- Body mass at hatchingmeasured
- 1.62g0.06 oz
1270 mm total length (Feldman et al. 2016), Shine 1994 (13 males 38.8-54, mean 47.7 cm SVL; 14 females 44.5-75.6, mean 58.7 cm SVL, see also Shine 1991), Ukuwela et al. 2022 (2 females 668-775 mm), Cox et al. 2012 (largestfemale 1075, largest male 838 mm TL)
snakes only in this source
largely converted from length by allometry in the source
How it lives
- Diet
- Carnivorous
- Active
- Cathemeral
- Where it lives
- Aquatic
- Habitat
- Forest, Wetlands
- Biome
- Tropical & Subtropical Moist Broadleaf Forests
- Region
- Oriental
- Mainland or island
- Mainland
- Range size
- 77,928km²
- Lowest it lives · above sea leveldisputed
- 19m
- Highest it lives · above sea leveldisputed
- 10m
fishes (Patel and Samal 2022, Ukuwela et al. 2022, Cox et al. 2012)
17:00 (Patel and Samal 2022) (recorded by Anuj Shinde), Nocturnal (Shine 1991), diurnal but has been encountered at night (Cox et al. 2012)
non-fossorial (Cyriac and Kodandaramaiah 2018), coastal waters (Patel and Samal 2022), semi aquatic (Cox et al. 2012)
mangroves and coastal waters (Cox et al. 2012) so I write -10 to 10
Breeding
- Reproduction
- Viviparous
- Sex decided by
- Genes, ZW/ZZ
- Average clutch
- 18eggs
- Eggs or young per clutch
- 5–38eggs
- Mean clutch
- 7–18eggs
Feldman et al. 2015, Cox et al. 2012
mean 18 (Meiri et al. 2019), 6-30 (Whitaker and Captain 2004), 6-8 mean=7 n=3 (Shine 1991), Shine 1994 (6-8, mean 7, n = 3 clutches), 5-38 (Cox et al. 2012)
Naming and history
- Suborder
- Serpentes
- Infraorder
- Alethinophidia
- Subspecies
- No
- Described by
- Schneider
- Moved to another genus · since it was first described
- Yes
- Described in
- 1799
- Type locality
- India
Keeping one
4 ft 2 in × 2 ft 1 in × 3 ft 2 in(127 × 64 × 95 cm)
Minimum length × width × height, for one animal. Bigger is always better.
The standard sizes snakes as a fraction of total length: 1 × 0.5 × 0.75.
Spends time in water, so a water area is part of the enclosure rather than a dish.
Mindestanforderungen an die Haltung von Reptilien (Sachverständigengutachten), German Federal Ministry for Nutrition, Agriculture and Forestry, Animal Welfare Division, 10 January 1997. The standard states these floor areas are recommendations rather than binding limits.
From this animal’s own total length of 4 ft 2 in (1270 mm), at 1 × 0.5 × 0.75 times it, following the German federal welfare standard — how this is worked out.
No preferred body temperature has been recorded for New Guinea bockadam. Rather than repeat a number from a care sheet, this page leaves it out.
Feeding
A prey item should be between the same width as the widest part of the snake's body and about 1.5 times that width.
Widely used across snake husbandry references. An alternative formulation gives prey at 10-15% of the snake's body mass. This is established practice, not a measurement.
137kJ per day
Worked out for an animal of 1,583 g, the heaviest recorded for New Guinea bockadam — so it is the top of the range, not a figure for a particular animal. Weigh yours and the number will be lower.
An upper estimate, not a feeding target, and not veterinary advice. The equation covers only what an animal burns staying alive, so a growing, gravid or recovering animal needs more — and it was measured on wild animals, which move far more than one in an enclosure. Body condition and a vet who knows the species are what a feeding decision should rest on. Where this comes from.
What nobody knows
These are not gaps in our research. No scientific dataset records them for this species — and saying so is information you cannot get from a reference that simply leaves a field out.
- — Length snout to vent · adult male mean
- — Length snout to vent · adult mean
- — Length nose to tail · adult male mean
- — Length nose to tail · adult mean
- — Largest female · snout to vent
- — Largest male · snout to vent
- — Largest female · shell length
- — Largest male · shell length
- — Hatchling length · snout to vent
- — Hatchling length · nose to tail
- — Largest juvenile · snout to vent
- — Largest juvenile · shell length
- — Egg length
- — Egg width
- — Body mass · a typical adult
- — Body mass · adult female, mean
- — Longest recorded life
- — Preferred body temperature · chosen in a laboratory gradient
- — Body temperature when active · measured in the wild
- — Eats arthropods
- — Eats vertebrates
- — Eats plant matter
- — How it hunts
- — How the young develop
- — Gestation or incubation
- — Clutches in a year
- — Clutches a year · fewest
- — Clutches a year · most
- — First breeds from · youngest recorded
- — First breeds by · oldest recorded
- — Hatchling length · smallest recorded
- — Hatchling length · largest recorded
- — Age at first breeding · female
- — Mature from · youngest recorded
- — Mature by · oldest recorded
- — Size at maturity · smallest recorded
- — Size at maturity · largest recorded
- — Venomous
- — Body temp in the wild · lowest mean recorded
- — Body temp in the wild · highest mean recorded
- — Colour on the back
- — Pattern on the back
- — Population trend
- — Red List criteria
- — Active season · shortest recorded
- — Active season · longest recorded
- — Density · lowest recorded
- — Density · highest recorded
- — Home range · largest recorded
- — Active in
Others in Homalopsidae
Take this data
Everything on this page is available as data under CC BY 4.0 — use it freely, credit it, no permission needed.
This species as JSON · the whole dataset
Cite this page
The Reptile & Amphibian Encyclopedia (2026). Cerberus rynchops. Retrieved 2026-09-08, from https://www.allanglescreatures.com/species/cerberus-rynchops
@misc{cerberus_rynchops_2026,
title = {Cerberus rynchops},
author = {{The Reptile & Amphibian Encyclopedia}},
year = {2026},
url = {https://www.allanglescreatures.com/species/cerberus-rynchops}
}Sources
- Meiri, S. (2024). SquamBase — a database of squamate (Reptilia: Squamata) traits. Global Ecology and Biogeography. Public domain (CC0).
- Oskyrko, O. et al. (2024). ReptTraits: a comprehensive dataset of ecological traits in reptiles. Scientific Data. Used under CC BY 4.0.
- Catalogue of Life (dataset 3LR), used under CC BY.