Reptilia · Squamata
Varanus beccariiDoria, 1874
Black Tree Monitor
Identification not confirmed. One observer recorded this animal as this species and no one has since agreed, so the photograph may show a different animal.
Photograph by Lythronax246, CC BY, via iNaturalist
A tree-dwelling, day-active, meat-eating monitor lizard from the Australo-Pacific region, reaching 340 mm snout to vent.
Reptilia › Squamata › Varanidae › Varanus
- Grows to
- 340mm
- greatest recorded
- Eats
- Carnivorous
- Active
- Diurnal
- Lives up to
- 22years
Longer than only 36% 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
37 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
- Data Deficient
- Status assessed · the year the Red List last looked
- 2014
- Population trend
- Decreasing
The animal itself
- Limbs
- Four legs
- Fangs
- None
- Longest recorded life
- 22years
16.8 for wild caught (still alive!), 15.3 for captive bred, 22 (pers. comm.) (Mendyk 2015)
Size
- Length snout to vent · greatest recorded
- 340mm13.5 in
- Length snout to vent · adult female mean
- 281.8mm11 in
- Largest female · snout to vent
- 281.8mm11 in
- Hatchling length · snout to vent
- 79.5mm3.25 in
- Largest juvenile · snout to vent
- 79.5mm3.25 in
- Body mass · greatestcomputed
- 773.3g1.7 lb
- Body mass at hatchingmeasured
- 10.5g0.37 oz
max 340 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
- Active
- Diurnal
- Where it lives
- Arboreal
- Habitat
- Forest
- Biome
- Tropical & Subtropical Moist Broadleaf Forests
- Region
- Australo-Pacific
- Mainland or island
- Found only on islands
- Highest it lives · above sea level
- 100m
- Range size
- 7854km²
Arthropods and small vertebrates
e.g., Auliya and Koch 2020
Breeding
- Reproduction
- Oviparous
- Sex decided by
- Genes, ZW/ZZ
- Average clutch
- 3.8eggs
- Eggs or young per clutch
- 1–6eggs
- Mean clutch
- 3.1–4.5eggs
- Clutches a year
- 0.66–3per year
- First breeds at
- 24–54.5months
mean 4.5 (Du et al. 2014), max 6 (Bennett 1995), 2-6 mean 3-4 (Auliya and Koch 2020)
Naming and history
- Suborder
- Sauria
- Infraorder
- Anguimoprha
- Subspecies
- No
- Described by
- Doria
- Moved to another genus · since it was first described
- Yes
- Described in
- 1874
- Type locality
- Indonesia
Keeping one
4 ft 6 in × 2 ft 9 in × 4 ft 6 in(136 × 85 × 136 cm)
Minimum length × width × height, for one animal. Bigger is always better.
The standard sizes climbing species at 4 × 2.5 × 4 times snout-vent length.
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 snout-vent length of 13.5 in (340 mm), at 4 × 2.5 × 4 times it, following the German federal welfare standard — how this is worked out.
No preferred body temperature has been recorded for Black Tree 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.
72kJ per day
Worked out for an animal of 773 g, the heaviest recorded for Black Tree 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 it hunts
- — 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
- — Pupil
- — 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 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 beccarii. Retrieved 2026-09-08, from https://www.allanglescreatures.com/species/varanus-beccarii
@misc{varanus_beccarii_2026,
title = {Varanus beccarii},
author = {{The Reptile & Amphibian Encyclopedia}},
year = {2026},
url = {https://www.allanglescreatures.com/species/varanus-beccarii}
}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.