Reptilia · Squamata
Tropidonophis mairiiGray, 1841
Common keelback
Photograph by dhfischer, CC BY, via iNaturalist
An active by day or night, meat-eating snake from the Australo-Pacific region, reaching 100 cm nose to tail.
Also called Mair’s keelback.
Reptilia › Squamata › Colubridae › Tropidonophis
- Grows to
- 1000mm
- greatest recorded
- Eats
- Carnivorous
- Active
- Cathemeral
- Lives up to
- 3years
Longer than 70% of all colubrid snakes 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 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
45 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
- Least Concern
- Status assessed · the year the Red List last looked
- 2014
- Population trend
- Stable
The animal itself
- Limbs
- None
- Pupil
- Round
- Fangs
- At the back of the mouth
- Longest recorded life
- 3years
rarely more than 2 (Shine et al. 2022), so I write 3
Size
- Length snout to vent · greatest recorded
- 770mm2 ft 6 in
- Length snout to vent · adult female mean
- 574mm22.5 in
- Length nose to tail · greatest recorded
- 1000mm3 ft 3 in
- Largest female · snout to vent
- 490.5mm19.5 in
- Largest male · snout to vent
- 568.5mm22.5 in
- Hatchling length · snout to vent
- 154mm6 in
- Largest juvenile · snout to vent
- 15.35mm0.6 in
- Body mass · greatestcomputed
- 225.4g8 oz
- Body mass · adult female, meanmeasured
- 127g4.5 oz
- Body mass at hatchingmeasured
- 2.72g0.1 oz
1000 mm total length (Feldman et al. 2016), Lettoof et al. 2023 (SVL 510 mm, mass 116 g), Shine 1994 (113 males 28.5-65.2, mean 49.1 cm SVL; 110 females 38.4-73.8, mean 57.4 cm SVL; hatchling SVL 154 mm, see also Shine 1991), Brown and Shine 2002 (207 mothers 48.0-77.0 cm, mean 61.9 cm, Post-partum mass 48.0-206.2, mean 111.4 g; litter mass 29.4, litter size 10.8, so hatchling mean 2.72 g)
snakes only in this source
snout-vent length; the source column mixes this with straight carapace length
computed from length by a family-level allometric equation, not weighed
How it lives
- Diet
- Carnivorous
- How it hunts
- Active foraging
- Active
- Cathemeral
- Where it lives
- Semi-aquatic
- Habitat
- Forest, Grassland, Wetlands
- Biome
- Tropical & Subtropical Grasslands, Savannas & Shrublands
- Active season · months of the year
- 12months
- Region
- Australo-Pacific
- Mainland or island
- Mainland
- Highest it lives · above sea level
- 1500m
- Range size
- 1,290,468km²
mostly frogs (Lettoof et al. 2023, Shine 1991), also fish, lizards and a mammal (Shine 1991)
Active (Glaudas et al. 2019)
Nocturnal (Shine 1991), cathemeral (Lettoof et al. 2023)
(Cogger 2018)/Terrestrial (Deepak et al. 2022, Lettoof et al. 2023 though Lettoof et al. 2023 say they mostly eat frogs)
1-1500 (O'Shea 2018)
Breeding
- Reproduction
- Oviparous
- Sex decided by
- Genes, ZW/ZZ
- Average clutch
- 9eggs
- Eggs or young per clutch
- 3–18eggs
- Mean clutch
- 9–10.8eggs
- Clutches a year
- 1–2per year
- Egg length
- 25.5mm1 in
- Egg width
- 14mm0.6 in
- First breeds at
- 6–9months
Feldman et al. 2015, Meiri et al. 2019
3-18 mean=9 s.d.=3.3 n=52 (Shine 1991), 3-18 (O'Shea 2018), Shine 1994 (3-18, mean 9, n = 52 clutches), Brown and Shine 2002 (mean 10.8 range 4-18, n = 207)
Naming and history
- Suborder
- Serpentes
- Infraorder
- Alethinophidia
- Subspecies
- Tropidonophis mairii mairii (GRAY 1841) Tropidonophis mairii plumbea (MACLEAY 1877)
- Described by
- Gray
- Moved to another genus · since it was first described
- Yes
- Described in
- 1841
- Type locality
- Australia
Keeping one
3 ft 3 in × 19.5 in × 2 ft 6 in(100 × 50 × 75 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.
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 3 ft 3 in (1000 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 Common keelback. 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.
24kJ per day
Worked out for an animal of 225 g, the heaviest recorded for Common keelback — 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
- — Female length · mean, nose to tail
- — Length nose to tail · adult male mean
- — Length nose to tail · adult mean
- — Largest female · shell length
- — Largest male · shell length
- — Hatchling length · nose to tail
- — Largest juvenile · shell length
- — Body mass · a typical adult
- — Preferred body temperature · chosen in a laboratory gradient
- — Body temperature when active · measured in the wild
- — Eats arthropods
- — Eats vertebrates
- — Eats plant matter
- — How the young develop
- — Gestation or incubation
- — Clutches in a year
- — 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
- — Red List criteria
- — 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). Tropidonophis mairii. Retrieved 2026-09-08, from https://www.allanglescreatures.com/species/tropidonophis-mairii
@misc{tropidonophis_mairii_2026,
title = {Tropidonophis mairii},
author = {{The Reptile & Amphibian Encyclopedia}},
year = {2026},
url = {https://www.allanglescreatures.com/species/tropidonophis-mairii}
}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.