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Squamata · ColubridaeEntry 8,847 of 21,572
Red-tailed Green Ratsnake, Gonyosoma oxycephalum

Reptilia · Squamata

Gonyosoma oxycephalumBoie, 1827

Red-tailed Green Ratsnake

Photograph by Bjørn Christian Tørrissen, CC BY-SA, via Wikimedia Commons

A tree-dwelling, day-active, meat-eating snake from the Oriental region, reaching 240 cm nose to tail.

Reptilia › Squamata › Colubridae › Gonyosoma

Grows to
2400mm
greatest recorded
Eats
Carnivorous
Active
Diurnal
Lives up to
22years
Body length across Colubridae

Longer than 98% of all colubrid snakes anyone has measured.

98% of 2,008 species are smaller2% larger
98 mmthe whole family, smallest to largest3,800 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 98 to 3,800 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

36 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

Body mass (a typical adult) is given as 5,399, and Body mass (greatest) as 937.9 — but a typical adult cannot outweigh the heaviest one ever recorded. 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
2011
Population trend
Decreasing

The animal itself

Limbs
None
Colour on the back
Green
Pattern on the back
Uniform
Pupil
Round
Venomous
No
Fangs
At the back of the mouth
Longest recorded life
22years

Stark et al. 2020 (22 years in captivity), Cox et al. 2012 (15 years, 2 months in captivity)

Size

Length nose to tail · greatest recorded
2400mm7 ft 10 in

snakes only in this source

Hatchling length · nose to tail
515mm20.5 in
Body mass at hatchingmeasured
14.5g0.51 oz
Body mass · greatestcomputeddisputed
937.9g2.1 lb

computed from length by a family-level allometric equation, not weighed

Body mass · a typical adultdisputed
5399g12 lb

AnAge rates this record "acceptable"

How it lives

Diet
Carnivorous

birds and small mammals including bats (Cox et al. 2012, Fujii et al. 2023)

Active
Diurnal

Stark et al. 2018, Cox et al. 2012, Fujii et al. 2023

Where it lives
Arboreal

Scharf et al. 2015, Cox et al. 2012, Fujii et al. 2023

Habitat
Forest, Shrubland
Biome
Tropical & Subtropical Moist Broadleaf Forests
Region
Oriental
Mainland or island
Mainland
Highest it lives · above sea level
1330m

0-1330 (Feldman 2015), 25-939 (Meneses et al. 2022), 0-1300 (Cox et al. 2012)

Range size
2,788,435km²

Breeding

Reproduction
Oviparous

Feldman et al. 2015

Average clutch
9eggs
Eggs or young per clutch
5–12eggs

mean 9 (Scharf et al. 2015), 6-12 (Whitaker and Captain 2004), 5-12 (Cox et al. 2012)

Mean clutch
9eggs

Naming and history

Suborder
Serpentes
Infraorder
Alethinophidia
Subspecies
No
Described by
Boie
Moved to another genus · since it was first described
Yes
Described in
1827
Type locality
Indonesia

Keeping one

5 ft 11 in × 3 ft 11 in × 11 ft 10 in(180 × 120 × 360 cm)

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

The standard sizes snakes as a fraction of total length: 0.75 × 0.5 × 1.5.

Lives in vegetation, so height and climbing structure matter more than floor space.

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 7 ft 10 in (2400 mm), at 0.75 × 0.5 × 1.5 times it, following the German federal welfare standard — how this is worked out.

No preferred body temperature has been recorded for Red-tailed Green Ratsnake. 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.

86kJ per day

Worked out for an animal of 938 g, the heaviest recorded for Red-tailed Green Ratsnake — 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 · 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
  • — Largest juvenile · snout to vent
  • — Largest juvenile · shell length
  • — Egg length
  • — Egg width
  • — Body mass · adult female, mean
  • — 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
  • — Body temp in the wild · lowest mean recorded
  • — Body temp in the wild · highest mean recorded
  • — Sex decided by
  • — Red List criteria
  • — Active season · shortest recorded
  • — Active season · longest recorded
  • — Density · lowest recorded
  • — Density · highest recorded
  • — Home range · largest recorded
  • — Active in
  • — Lowest it lives · above sea level

Others in Colubridae

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). Gonyosoma oxycephalum. Retrieved 2026-09-08, from https://www.allanglescreatures.com/species/gonyosoma-oxycephalum

@misc{gonyosoma_oxycephalum_2026,
  title  = {Gonyosoma oxycephalum},
  author = {{The Reptile & Amphibian Encyclopedia}},
  year   = {2026},
  url    = {https://www.allanglescreatures.com/species/gonyosoma-oxycephalum}
}

Sources

  1. Meiri, S. (2024). SquamBase — a database of squamate (Reptilia: Squamata) traits. Global Ecology and Biogeography. Public domain (CC0).
  2. Oskyrko, O. et al. (2024). ReptTraits: a comprehensive dataset of ecological traits in reptiles. Scientific Data. Used under CC BY 4.0.
  3. Catalogue of Life (dataset 3LR), used under CC BY.
  4. AnAge, Human Ageing Genomic Resources (de Magalhães et al.), used under CC BY 3.0.