All Angles Creatures
Squamata · VaranidaeEntry 21,171 of 21,572
Nile Monitor, Varanus niloticus

Reptilia · Squamata

Varanus niloticusLinnaeus, 1766

Nile Monitor

Photograph by Ben Machado, CC BY, via iNaturalist

A day-active, meat-eating monitor lizard from the Afrotropic region, reaching 980 mm snout to vent.

Also called Water Leguaan.

Once published as Varanus ornatus — those names reach this page.

Reptilia › Squamata › Varanidae › Varanus

Grows to
980mm
greatest recorded
Eats
Carnivorous
Active
Diurnal
Lives up to
23years
Body length across Varanidae

Longer than 96% of all monitor lizards anyone has measured.

96% of 84 species are smaller4% larger
116.4 mmthe whole family, smallest to largest1,570 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 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

46 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
2019
Population trend
Stable

The animal itself

Limbs
Four legs
Fangs
None
Longest recorded life
23years

Carey and Judge 2000, De Magalhaes & Costa 2009: 14.6 (in captivity), Castanet 1994: 15, Slavens and Slavens 1999: 14 and 7 months, Hughes 1988, 102 months (de Buffrenil and Hemery 2002); 10-20 (ADW), 23 (Mendyk 2015)

Preferred body temperature · chosen in a laboratory gradientmeasured
34.8°C
Body temperature when active · measured in the wild
30.75°C87 °F

mean body temperature of active individuals in nature

Body temp in the wild · mean, when active
28.8–32.7°C84–91 °F

body temperature of active animals in nature

Size

Length snout to vent · greatest recorded
980mm3 ft 3 in

max 980 mm SVL (Feldman et al. 2016)

Length snout to vent · adult female mean
499.4mm19.5 in
Largest female · snout to vent
499.7mm19.5 in

snout-vent length; the source column mixes this with straight carapace length

Hatchling length · snout to vent
127.5mm5 in
Largest juvenile · snout to vent
127.5mm5 in
Body mass · greatestcomputed
23,747g52 lb

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

Body mass · a typical adult
2826.7g6.2 lb

AnAge rates this record "acceptable"

Body mass · adult female, meanmeasured
4000g8.8 lb
Body mass at hatchingmeasured
23g0.81 oz

How it lives

Diet
Carnivorous

invertebrates (mostly mollusks, Losos and Greene 1988), vertebrates (e.g., frogs, lizards, snakes, birds and small mammals, Alexander and Marais 2007, Reid 1986) and crocodyle eggs, see aslo Arbuckle 2009, Branch 2014, invertebrates, vertebrates and carrion (Auliya and Koch 2020), everything (van Huyssteen 2023)

How it hunts
Active foraging

e.g., Bowker 1984, van Huyssteen 2023

Active
Diurnal

(e.g., Kenya Reptile Atlas (http://kenyareptileatlas.com/, Auliya and Koch 2020, van Huyssteen 2023, Malonza and Bwong 2023, Spawls et al. 2023)

Where it lives
Semi-aquatic

Semi Aquatic and Terrestrial (e.g., Malonza and Bwong 2023)/ terrestrial juveniles more arboreal (Auliya and Koch 2020), semi aquatic (Pietersen et al. 2021), semi aquatic, saxicolous and terrestrial (van Huyssteen 2023), versatile: runs, climbs, swims (Spawls et al. 2023)

Habitat
Forest, Savanna, Shrubland, Wetlands
Biome
Tropical & Subtropical Grasslands, Savannas & Shrublands
Region
Afrotropic
Mainland or island
Mainland
Highest it lives · above sea level
2000m

0-1600 (Kenya Reptile Atlas (http://kenyareptileatlas.com/, Malonza and Bwong 2023), 560m (Portik et al. 2016), 0 to about 2000 (Spawls et al. 2023)

Range size
15,915,085km²
Density
0.4–0.6per hectare

Breeding

Reproduction
Oviparous
Sex decided by
Genes, ZW/ZZ
Average clutch
23.38eggs
Eggs or young per clutch
5–63eggs

mean 23.2 (Du et al. 2014), 15-60 (Kenya Reptile Atlas (http://kenyareptileatlas.com/), up to 60 (Branch 2016), 20-60 (Spawls et al. 2018, Spawls et al. 2023), 5-60 mean 25 (Auliya and Koch 2020), 16-60 (Pietersen et al. 2021)

Mean clutch
19.5–27.3eggs
Clutches in a year
1per year
Clutches a year
1per year
First breeds at
24months
Age at first breeding · female
1278days

Naming and history

Suborder
Sauria
Infraorder
Anguimoprha
Subspecies
No
Described by
Linnaeus
Moved to another genus · since it was first described
Yes
Described in
1766
Type locality
Egypt

Keeping one

12 ft 10 in × 12 ft 10 in × 8 ft(392 × 392 × 245 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 3 ft 3 in (980 mm), at 4 × 4 × 2.5 times it, following the German federal welfare standard — how this is worked out.

In a laboratory thermal gradient this species settled at 95 °F (34.8 °C).

Preferred body temperature, recorded in a laboratory gradient where the animal could choose freely. 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.

1521kJ per day

Worked out for an animal of 23,747 g, the heaviest recorded for Nile 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
  • — Eats arthropods
  • — Eats vertebrates
  • — Eats plant matter
  • — How the young develop
  • — Gestation or incubation
  • — Hatchling length · smallest recorded
  • — Hatchling length · largest recorded
  • — Mature from · youngest recorded
  • — Mature by · oldest recorded
  • — Size at maturity · smallest recorded
  • — Size at maturity · largest recorded
  • — Venomous
  • — Colour on the back
  • — Pattern on the back
  • — Pupil
  • — Red List criteria
  • — Active season · shortest recorded
  • — Active season · longest 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 niloticus. Retrieved 2026-09-08, from https://www.allanglescreatures.com/species/varanus-niloticus

@misc{varanus_niloticus_2026,
  title  = {Varanus niloticus},
  author = {{The Reptile & Amphibian Encyclopedia}},
  year   = {2026},
  url    = {https://www.allanglescreatures.com/species/varanus-niloticus}
}

Sources

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