Crocodylus siamensisSchneider, 1801

Siamese crocodile

Photograph by James Hunt, CC BY, via iNaturalist

A nocturnal, meat-eating crocodilian from the Oriental region, reaching 400 cm nose to tail.

Reptilia › Crocodylia › Crocodylidae › Crocodylus

Grows to: 4000mm; greatest recorded
Eats: Carnivorous
Active: Nocturnal
Lives up to: 21.1years

What is known

30 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

Conservation status: Critically Endangered
Population trend: Decreasing

The animal itself

Colour on the back: Green
Pattern on the back: Uniform
Pupil: Vertical slit
Venomous: No
Fangs: None
Longest recorded life: 21.1years
Body temperature when active · measured in the wild: 29.5°C85 °F

Size

Length nose to tail · greatest recorded: 4000mm13 ft 1 in
Body mass · greatestcomputed: 350,000g772 lb
Body mass · a typical adult: 42,500g94 lb
Body mass at hatching: 105.5g3.7 oz

How it lives

Diet: Carnivorous
How it hunts: Active foraging
Active: Nocturnal
Where it lives: Arboreal, saxicolous, terrestrial
Habitat: Wetlands
Region: Oriental
Highest it lives · above sea level: 730m

Breeding

Reproduction: Oviparous
Sex decided by: Temperature
Average clutch: 27.2eggs
Eggs or young per clutch: 15–50eggs
Egg length: 78.2mm3 in
Egg width: 48.1mm2 in

Naming and history

Subspecies: No
Described by: Schneider
Moved to another genus · since it was first described: No
Described in: 1801

Keeping one

Siamese crocodile is assessed as Critically Endangered 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.

Active animals measured in the wild averaged 85 °F (29.5 °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.

16632kJ per day

Worked out for an animal of 350,000 g, the heaviest recorded for Siamese crocodile — 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.

Other inherited traits

Inherited characteristics and conditions recorded for this species. These are not morphs — nobody breeds for them.

Post-occipital scutes, variation in number1 reference

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.

— Still living
— Length snout to vent · greatest recorded
— Length snout to vent · adult female mean
— Length snout to vent · adult male mean
— Length snout to vent · adult mean
— Female length · mean, nose to tail
— 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
— Body mass · adult female, mean
— Preferred body temperature · chosen in a laboratory gradient
— Eats arthropods
— Eats vertebrates
— Eats plant matter
— How the young develop
— Gestation or incubation
— Mean clutch · smallest reported
— Mean clutch · largest reported
— 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
— Body temp in the wild · lowest mean recorded
— Body temp in the wild · highest mean recorded
— Limbs
— Status assessed · the year the Red List last looked
— Red List criteria
— Biome
— Active season · shortest recorded
— Active season · longest recorded
— Density · lowest recorded
— Density · highest recorded
— Home range · largest recorded
— Suborder
— Infraorder
— Type locality
— Active in
— Mainland or island
— Lowest it lives · above sea level
— Range size

Others in Crocodylidae

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). Crocodylus siamensis. Retrieved 2026-09-08, from https://www.allanglescreatures.com/species/crocodylus-siamensis

@misc{crocodylus_siamensis_2026,
  title  = {Crocodylus siamensis},
  author = {{The Reptile & Amphibian Encyclopedia}},
  year   = {2026},
  url    = {https://www.allanglescreatures.com/species/crocodylus-siamensis}
}

Sources

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.