Squamata · AgamidaeEntry 15,886 of 21,572

Reptilia · Squamata

Physignathus cocincinusCuvier, 1829

Thai Water Dragon

Photograph by Rushenb, CC BY-SA, via Wikimedia Commons

A day-active, meat-eating lizard from the Oriental region, reaching 280 mm snout to vent.

Also called Asian water dragon, Chinese Water Dragon, Green Water Dragon.

Reptilia › Squamata › Agamidae › Physignathus

Grows to: 280mm; greatest recorded
Eats: Carnivorous
Active: Diurnal
Lives up to: 18years

Body length across Agamidae

Longer than 98% of all agamids anyone has measured.

98% of 583 species are smaller2% larger

32 mmthe whole family, smallest to largest418 mm

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 32 to 418 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

41 sourced facts, each taken from a named scientific dataset. How to read these.

Cited from a dataset unless a row is marked otherwise.

Standing in the world

Still living: Extant
Conservation status: Vulnerable
Status assessed · the year the Red List last looked: 2017
Population trend: Decreasing
Red List criteria: A4cd

The animal itself

Limbs: Four legs
Venomous: No
Fangs: None
Longest recorded life: 18years
Body temperature when active · measured in the wild: 28.35°C83 °F
Body temp in the wild · mean, when active: 25.7–31°C78–88 °F

Size

Length snout to vent · greatest recorded: 280mm11 in
Length snout to vent · adult female mean: 156.9mm6.25 in
Largest female · snout to vent: 156.9mm6.25 in
Hatchling length · snout to vent: 41.5mm1.75 in
Largest juvenile · snout to vent: 41.5mm1.75 in
Body mass · greatestcomputed: 817.4g1.8 lb
Body mass · a typical adult: 193.4g6.8 oz

How it lives

Diet: Carnivorous
Active: Diurnal
Where it lives: Semi-aquatic
Habitat: Forest, Wetlands
Biome: Tropical & Subtropical Moist Broadleaf Forests
Region: Oriental
Mainland or island: Mainland
Elevation · above sea level: 60–900m
Range size: 1,243,356km²

Breeding

Reproduction: Oviparous
Average clutch: 10.36eggs
Eggs or young per clutch: 4–23eggs
Mean clutch: 10.4eggs
Clutches in a year: 1.5per year
Clutches a year: 1–2per year
First breeds at: 18–60months

Naming and history

Suborder: Sauria
Infraorder: Acrodontia
Subspecies: No
Described by: Cuvier
Moved to another genus · since it was first described: No
Described in: 1829
Type locality: Vietnam

Keeping one

Thai Water Dragon is assessed as Vulnerable on the IUCN Red List. Species at risk in the wild are often covered by CITES and by national law, which decide what may be bought, sold, moved across a border or kept at all — and captive-bred and wild-caught animals are usually treated differently. Check the rules where you are before acquiring one. Nothing below is a judgement about keeping this species; it is what a published welfare standard says about space, and what the animal itself was measured doing.

3 ft 8 in × 3 ft 8 in × 2 ft 4 in(112 × 112 × 70 cm)

Minimum length × width × height, for one animal. Bigger is always better.

The standard sizes ground-dwelling species at 4 × 4 × 2.5 times snout-vent length.

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 snout-vent length of 11 in (280 mm), at 4 × 4 × 2.5 times it, following the German federal welfare standard — how this is worked out.

Active animals measured in the wild averaged 83 °F (28.4 °C).

Mean body temperature of active individuals measured in nature. A measurement of the animal, not a setting for a thermostat.

Feeding

A prey item should be no wider than the space between the animal's eyes.

Widely used across reptile husbandry references. The stated reason is that the gap approximates the width of the throat, so wider prey is associated with impaction. This is established practice, not a measurement.

76kJ per day

Worked out for an animal of 817 g, the heaviest recorded for Thai Water Dragon — 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.

Morphs

0 with peer-reviewed genetics behind them, 1 resting on breeder consensus. Most references present both with the same confidence.

Colour and conditionbreeder consensus
How green an animal is and how strongly the throat and flank stripes show. Males are larger with a bigger crest and jowls; colour also shifts with temperature and condition.
Worth knowing. No single-gene morph is established. What this species is known for in captivity is snout damage: water dragons see through glass and run into it repeatedly, rubbing their noses raw. It is caused by the enclosure — visual barriers and planting are the usual answer — rather than by anything wrong with the animal.

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 · greatest recorded
— Female length · mean, nose to tail
— Length nose to tail · adult male mean
— Length nose to tail · adult mean
— Largest male · snout to vent
— Largest female · shell length
— Largest male · shell length
— Hatchling length · nose to tail
— Largest juvenile · shell length
— Egg length
— Egg width
— Body mass · adult female, mean
— Body mass at hatching
— Preferred body temperature · chosen in a laboratory gradient
— Eats arthropods
— Eats vertebrates
— Eats plant matter
— How it hunts
— How the young develop
— Gestation or incubation
— 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
— Colour on the back
— Pattern on the back
— Pupil
— Sex decided by
— Active season · shortest recorded
— Active season · longest recorded
— Density · lowest recorded
— Density · highest recorded
— Home range · largest recorded
— Active in

Others in Agamidae

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). Physignathus cocincinus. Retrieved 2026-09-08, from https://www.allanglescreatures.com/species/physignathus-cocincinus

@misc{physignathus_cocincinus_2026,
  title  = {Physignathus cocincinus},
  author = {{The Reptile & Amphibian Encyclopedia}},
  year   = {2026},
  url    = {https://www.allanglescreatures.com/species/physignathus-cocincinus}
}

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.
AnAge, Human Ageing Genomic Resources (de Magalhães et al.), used under CC BY 3.0.