Reptilia · Squamata
Varanus mitchelliMertens, 1958
Mitchell's Water Monitor
Photograph by Graham Winterflood, CC BY-SA, via iNaturalist
A day-active, meat-eating monitor lizard from the Australo-Pacific region, reaching 346 mm snout to vent.
Reptilia › Squamata › Varanidae › Varanus
- Grows to
- 346mm
- greatest recorded
- Eats
- Carnivorous
- Active
- Diurnal
- Lives up to
- 12years
Longer than only 37% of all monitor lizards 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 116.4 to 1,570 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.
Standing in the world
- Still living
- Extant
- Conservation status
- Critically Endangered
- Status assessed · the year the Red List last looked
- 2017
- Population trend
- Decreasing
- Red List criteria
- A4be
The animal itself
- Limbs
- Four legs
- Fangs
- None
- Longest recorded life
- 12years
Carey and Judge 2000, Slavens and Slavens 1999: 6 and 7 months, 8 (Mendyk 2015), Gaikhorst et al. 2010 report a male collected as adult in 1997 was still reproducing in 2005, given they say 3 year animals are still juveniles it would be at least 12
Size
- Length snout to vent · greatest recorded
- 346mm13.5 in
- Length snout to vent · adult female mean
- 236mm9.25 in
- Largest female · snout to vent
- 236mm9.25 in
- Hatchling length · snout to vent
- 61.9mm2.5 in
- Largest juvenile · snout to vent
- 68mm2.75 in
- Body mass · greatestcomputed
- 818.3g1.8 lb
- Body mass at hatchingmeasured
- 4.06g0.14 oz
max 346 mm SVL (Feldman et al. 2016)
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
- Mixed
- Active
- Diurnal
- Where it lives
- Semi-aquatic
- Habitat
- Wetlands
- Biome
- Tropical & Subtropical Grasslands, Savannas & Shrublands
- Region
- Australo-Pacific
- Mainland or island
- Mainland
- Range size
- 449,923km²
fish and frogs, lizards, Terrestrial invertebrates, terrestrial vertebrates and crabs (e.g., Arbuckle 2009), "largely of fish and crabs. together with frogs, lizards, reptile eggs, small mammals, nestling birds and terrestrial invertebrates (orthopterans, arachnids. beetles etc. )." (Bennett 1995), see also Gaikhorst et al. 2010, grasshoppers spiders and fish (Auliya and Koch 2020)
sit and wait (Clemente et al. 2009) / active forager (Gaikhorst et al. 2010)
e.g, Auliya and Koch 2020
Arboreal and semi-Aquatic (e.g., Thompson et al. 2008), semi aquatic implied in Gaikhorst et al. 2010, terrestrial and arboreal (Auliya and Koch 2020)
Breeding
- Reproduction
- Oviparous
- Average clutch
- 11.85eggs
- Eggs or young per clutch
- 3–27eggs
- Mean clutch
- 9.8–18.9eggs
- Clutches a year
- 3–6per year
mean 20 (Du et al. 2014), up to 12 (Bennett 1995), 13-27, mean 20 (Gaikhorst et al. 2010, but this is excluding a clutch of 8, so assuming it is mean 20 over 10 clutches because there were 11 overall mean is 208/11 = 18.9), "7-12 eggs per clutch in the wild, in captivity 13-27 eggs per clutch"
Naming and history
- Suborder
- Sauria
- Infraorder
- Anguimoprha
- Subspecies
- No
- Described by
- Mertens
- Moved to another genus · since it was first described
- No
- Described in
- 1958
- Type locality
- Australia
Keeping one
Mitchell's Water Monitor 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.
4 ft 6 in × 4 ft 6 in × 2 ft 10 in(138 × 138 × 87 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 13.5 in (346 mm), at 4 × 4 × 2.5 times it, following the German federal welfare standard — how this is worked out.
No preferred body temperature has been recorded for Mitchell's Water Monitor. Rather than repeat a number from a care sheet, this page leaves it out.
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 818 g, the heaviest recorded for Mitchell's Water Monitor — 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 · 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 · a typical adult
- — 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 the young develop
- — Gestation or incubation
- — Clutches in a year
- — 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
- — Pupil
- — Sex decided by
- — 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
- — Highest it lives · above sea level
Others in Varanidae
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). Varanus mitchelli. Retrieved 2026-09-08, from https://www.allanglescreatures.com/species/varanus-mitchelli
@misc{varanus_mitchelli_2026,
title = {Varanus mitchelli},
author = {{The Reptile & Amphibian Encyclopedia}},
year = {2026},
url = {https://www.allanglescreatures.com/species/varanus-mitchelli}
}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.