Nile Monitor (Varanus niloticus)
ReptileLizardAfrica
A Nile monitor resting on an earth mound in Queen Elizabeth National Park, Uganda.
Image: Giles Laurent, CC BY-SA 4.0, via Wikimedia Commons.
Overview
The Nile monitor (Varanus niloticus) is a large lizard native to most of sub-Saharan Africa and, along the Nile, to Egypt. It lives near water in almost any habitat except deserts, on land and in the water alike, and it has been introduced to southern Florida, where breeding populations are established.
It has a long neck, strong claws, bead-like scales and a long tail flattened from side to side, with a low crest. Adults are gray-brown to olive with darker reticulation and six to nine crossbands or rows of yellow eye-spots across the back, and the forked tongue is blue; the young are patterned in black and bright yellow. One account says males and females look alike.
One account gives an average snout-vent length of 0.6–0.8 m; another says adults grow to about 100–140 cm in total length, with a tail much longer than the body — figures that do not fit together — and the maximum is given as about 200 cm in two accounts and as 2.4 m, 243 cm or more than 2.42 m in others; it is described as Africa's longest lizard. Average adult mass is given as 2,827 g, and maximum mass as up to 8.1 kg or over 10 kg; large males removed in Florida weighed more than 12 kg.
Habitat & Range
Nile monitors live near water in grassland, savanna, scrub, woodland, forest, swamps and mangroves and along rivers, lakes and seashores, but not in deserts. Two accounts tie them to permanent water, while another says temporary or permanent water, especially rivers, lakes and pans. They climb and swim well, shelter in burrows they dig or take over, need open places to bask, and readily live around human settlements.
The species is recorded from Senegal and Mauritania to Ethiopia, Somalia and South Africa and north along the Nile into Egypt, and it is absent from the arid north and southwest. Under the taxonomic authority followed here, that range includes a western lineage that a genetic study matched to the old nameTupinambis stellatus, and the form once treated as Varanus ornatus, which one account still treats as a separate species. In Florida, three breeding populations — around Cape Coral, West Palm Beach and Homestead Air Reserve Base — stem from three separate introductions, all from the southern coastal region of West Africa; a Florida research project lists breeding populations in Lee and Palm Beach counties and says others may exist in Miami-Dade and Broward counties. In Lee County the lizards use canals, estuaries, pine flatwoods, barrier islands, suburbs and golf-course ponds.
Diet
The Nile monitor is a generalist carnivore and scavenger that eats almost any animal it can overpower: mollusks, crabs, insects, fish, frogs and toads, lizards, snakes, turtles, birds and their eggs, small mammals, young crocodiles and carrion. Land snails of the genus Achatina are called its favorite prey, and its blunt crushing teeth and bowed lower jaw are suited to breaking shells. It has been known to raid crocodile nests for eggs, and it also eats human food scraps, and hatchlings eat insects, spiders, snails and other small animals. In Cape Coral, Florida, stomach contents included whole clutches of reptile and bird eggs and an adult burrowing owl.
Behavior
Nile monitors are active by day. When not on the move they bask or rest on waterside vegetation, trees, logs and rocks, often in a prominent position, and they sometimes climb trees to bask, feed or sleep; while active they are mainly in the water, often hidden in dense vegetation in the shallows. In the colder, temperate parts of South Africa they hibernate during cold weather in big rock cracks or burrows.
Nile monitors are usually solitary, with only occasional contact outside the mating season. Mating is promiscuous, males may reportedly fight in wrestling matches, and two monitors may occasionally work together to raid a crocodile nest, one distracting the guarding female while the other takes the eggs. The young often stay in groups in which one may act as a temporary leader; they lick, groom and rub against one another and often sleep together on branches at night.
Human Interaction & Conservation
The Nile monitor is much exploited in Africa for its meat and skin, and to a lesser extent for the pet trade. Overexploitation for skins has driven it to local extinction in places, and its international trade is regulated under CITES Appendix II. It occasionally attacks chickens, and its melted fat is locally believed to cure earache and protect against lightning. Its size and defensive disposition make it potentially dangerous to people and pets.
In Florida, releases by reptile dealers and enthusiasts probably founded the invasive populations. There the species is a threat to native wildlife, including American crocodiles, sea turtles and burrowing owls, and it could threaten waterbirds if it spreads into sensitive areas; researchers are evaluating whether containment or eradication is possible. IUCN's global assessment lists the Nile monitor as Least Concern (2021).
Reproduction & Life Cycle
Nile monitors breed once a year, usually mating and laying after the rains, which vary by region. One account places the season between June and October, with laying after the August–September rains, while another puts laying in Africa from August to early January. Females lay 20 to 60 eggs in holes in the ground, burrows or active termite mounds. Incubation is given as 6–9 months, apparently 6–10 months in the wild, or as possibly requiring 10 months, though captive eggs have hatched in as few as 129 days. Most authors say the young hatch out unaided, but one author suggests that females return to dig them out.
Hatchlings are about 30 cm long and weigh about 26 g. Monitors mature at three to four years, although in Mali and Chad females mature at about 24 months and a snout-vent length of 36 cm, and about half of the mature females there breed each year. In Cape Coral, Florida, breeding runs from April to September, and hatchlings appear mainly from February to April. Parthenogenesis may occur.
In captivity the expected lifespan is reported as 10–20 years, although the longest recorded captive lifespan is 14.6 years. Where the setting is not stated, accounts say individuals may live more than 10–15 years, or as long as 10 to 15 years.
Sourced facts
Each value below is traced to the specific reference that states it. Open a row's evidence to see the source, where to look in it, and how firmly it supports the value. Sources checked 2026-10-20.
| Fact | What the source states | Evidence |
|---|---|---|
| Distinguishing traits | Large, with a long neck, strong claws, bead-like scales and a long, laterally compressed tail with a low crest. Adults are gray-brown to olive with darker reticulation and 6–9 crossbands or rows of yellow ocelli on the back; the tongue is blue. Young are black and bright yellow.The belly and throat are paler, with black bars; the rounded nostrils sit slightly nearer the eye than the snout, and the tongue is forked. One account says the sexes look alike. No lizard native to the United States reaches this size with these features. | Matches source · The Reptile Database (Uetz et al.; new species and updates by the Zoological Museum Hamburg), U.S. Geological Survey, Nonindigenous Aquatic Species Database, Animal Diversity Web (University of Michigan Museum of Zoology), South African National Biodiversity Institute (SANBI), Animal of the week — how we knowThe Reptile Database (Uetz et al.; new species and updates by the Zoological Museum Hamburg)
U.S. Geological Survey, Nonindigenous Aquatic Species Database
Animal Diversity Web (University of Michigan Museum of Zoology)
South African National Biodiversity Institute (SANBI), Animal of the week
|
| Geographic range | Native to most of sub-Saharan Africa and north along the Nile into Egypt, but absent from deserts and from the arid north and southwest. Introduced to the United States, where breeding populations are established in southern Florida.Recorded from Senegal and Mauritania to Ethiopia, Somalia and South Africa; two accounts describe the range as central and southern Africa, including Sudan. It includes a western lineage that a genetic study matched to Tupinambis stellatus, and the taxonomic authority includes the form once treated as V. ornatus, which a genetic study found genetically indistinguishable; one account still treats that form as a separate species. Florida's three breeding populations (Cape Coral, West Palm Beach and Homestead Air Reserve Base) stem from three separate introductions, all from the southern coastal region of West Africa; a Florida research project, which lists breeding populations in Lee and Palm Beach counties, says populations may also exist in Miami-Dade and Broward counties. | Matches source · The Reptile Database (Uetz et al.; new species and updates by the Zoological Museum Hamburg), Animal Diversity Web (University of Michigan Museum of Zoology), South African National Biodiversity Institute (SANBI), Animal of the week, U.S. Geological Survey, Nonindigenous Aquatic Species Database, University of Florida IFAS, Fort Lauderdale Research and Education Center (The Croc Docs), SUNY Open Access Repository (record of Dowell et al. 2016, Royal Society Open Science 3: 150619), SUNY Open Access Repository (record of Dowell et al. 2016, Molecular Phylogenetics and Evolution 94: 591-604) — how we knowThe Reptile Database (Uetz et al.; new species and updates by the Zoological Museum Hamburg)
Animal Diversity Web (University of Michigan Museum of Zoology)
South African National Biodiversity Institute (SANBI), Animal of the week
U.S. Geological Survey, Nonindigenous Aquatic Species Database
University of Florida IFAS, Fort Lauderdale Research and Education Center (The Croc Docs)
SUNY Open Access Repository (record of Dowell et al. 2016, Royal Society Open Science 3: 150619)
SUNY Open Access Repository (record of Dowell et al. 2016, Molecular Phylogenetics and Evolution 94: 591-604)
|
| Habitat | Found near water in almost any habitat except deserts: grassland, savanna, scrub, woodland, forest, swamps, mangroves, rivers, lakes and seashores. Both terrestrial and aquatic, it climbs and swims well, shelters in burrows it digs or takes over, and needs open basking sites.Two accounts tie it to permanent water; another says temporary or permanent water, especially rivers, lakes and pans. It readily lives around human settlements. In Lee County, Florida, it uses estuarine areas, pine flatwoods, barrier islands, a 644 km canal network, suburbs and golf-course ponds, with home burrows common along canal banks; across Florida, mangrove swamps, marsh edges and the banks of rivers, canals and lakes are probably the most suitable habitats. | Matches source · Animal Diversity Web (University of Michigan Museum of Zoology), U.S. Geological Survey, Nonindigenous Aquatic Species Database, Global Invasive Species Database (IUCN SSC Invasive Species Specialist Group), South African National Biodiversity Institute (SANBI), Animal of the week — how we knowAnimal Diversity Web (University of Michigan Museum of Zoology)
U.S. Geological Survey, Nonindigenous Aquatic Species Database
Global Invasive Species Database (IUCN SSC Invasive Species Specialist Group)
South African National Biodiversity Institute (SANBI), Animal of the week
|
| Diet | A generalist carnivore and scavenger that eats almost any animal it can overpower: mollusks, crabs, insects, fish, frogs and toads, lizards, snakes, turtles, birds and their eggs, small mammals, young crocodiles and carrion. Hatchlings eat insects, spiders, snails and other small animals.Land snails of the genus Achatina are called its favorite prey, and its blunt crushing teeth and bowed lower jaw suit breaking shells. It has been known to raid crocodile nests for eggs. Human food scraps and feces are also eaten. In Cape Coral, Florida, stomach contents included whole clutches of reptile and bird eggs and an adult burrowing owl. | Matches source · Animal Diversity Web (University of Michigan Museum of Zoology), U.S. Geological Survey, Nonindigenous Aquatic Species Database, Global Invasive Species Database (IUCN SSC Invasive Species Specialist Group), South African National Biodiversity Institute (SANBI), Animal of the week — how we knowAnimal Diversity Web (University of Michigan Museum of Zoology)
U.S. Geological Survey, Nonindigenous Aquatic Species Database
Global Invasive Species Database (IUCN SSC Invasive Species Specialist Group)
South African National Biodiversity Institute (SANBI), Animal of the week
|
| Body size | Snout-vent length averages 0.6–0.8 m in one account, and reaches up to about 80 cm in another. Adults grow to about 100–140 cm total length; the maximum is given as about 200 cm, or as 2.4 m, 243 cm or more than 2.42 m. Hatchlings are about 30 cm long.sources disagreeTotal length includes the tail, which is much longer than the body. Described as Africa's longest lizard. Among more than 100 lizards removed around Cape Coral, Florida, large males reached nearly 2 m. One account treats a former subspecies as a separate species (V. ornata) that may be as big or bigger. | Sources disagree · U.S. Geological Survey, Nonindigenous Aquatic Species Database, The Reptile Database (Uetz et al.; new species and updates by the Zoological Museum Hamburg), South African National Biodiversity Institute (SANBI), Animal of the week, Animal Diversity Web (University of Michigan Museum of Zoology), Global Invasive Species Database (IUCN SSC Invasive Species Specialist Group) — how we knowWhat each reading says
Maximum total length differs: about 200 cm in two accounts, against 2.4 m, 243 cm, or more than 2.42 m in three others. Snout-vent length also does not fit together: one account's average of 0.6–0.8 m reaches another's maximum of about 80 cm, and with a tail much longer than the body it would exceed the usual total length of 100–140 cm given by a third. U.S. Geological Survey, Nonindigenous Aquatic Species Database
The Reptile Database (Uetz et al.; new species and updates by the Zoological Museum Hamburg)
South African National Biodiversity Institute (SANBI), Animal of the week
Animal Diversity Web (University of Michigan Museum of Zoology)
Global Invasive Species Database (IUCN SSC Invasive Species Specialist Group)
|
| Body mass | Average adult mass 2,827 g. Maximum mass is given as up to 8.1 kg or as over 10 kg, and large males removed in Florida exceeded 12 kg. Hatchlings weigh about 26 g.sources disagreeThe 2,827 g average comes from a life-history database. The 8.1 kg maximum is cited from a 1996 work. The Florida males were among more than 100 lizards removed around Cape Coral. The maxima are not given by sex. | Sources disagree · Human Ageing Genomic Resources: AnAge, The Animal Ageing and Longevity Database (Build 15), Global Invasive Species Database (IUCN SSC Invasive Species Specialist Group), U.S. Geological Survey, Nonindigenous Aquatic Species Database, Animal Diversity Web (University of Michigan Museum of Zoology) — how we knowWhat each reading says
Maximum mass differs: up to 8.1 kg in one account and over 10 kg in another. Human Ageing Genomic Resources: AnAge, The Animal Ageing and Longevity Database (Build 15)
Global Invasive Species Database (IUCN SSC Invasive Species Specialist Group)
U.S. Geological Survey, Nonindigenous Aquatic Species Database
Animal Diversity Web (University of Michigan Museum of Zoology)
|
| Lifespan | Captivity: expected 10–20 years (an estimate shared by two accounts); the longest recorded captive lifespan is 14.6 years. Setting not stated: may live more than 10–15 years, or as long as 10 to 15 years.sources disagreeThe 10–20-year captive estimate appears in identical wording in two accounts, which note that estimates vary; it runs past the 14.6-year captive record (sample size medium, data quality acceptable). The as-long-as figure rests on anecdotal observations. | Sources disagree · Animal Diversity Web (University of Michigan Museum of Zoology), South African National Biodiversity Institute (SANBI), Animal of the week, Human Ageing Genomic Resources: AnAge, The Animal Ageing and Longevity Database (Build 15), U.S. Geological Survey, Nonindigenous Aquatic Species Database, Global Invasive Species Database (IUCN SSC Invasive Species Specialist Group) — how we knowWhat each reading says
Where the setting is not stated, one account says individuals may live more than 10–15 years, while another says the species may live as long as 10 to 15 years. Animal Diversity Web (University of Michigan Museum of Zoology)
South African National Biodiversity Institute (SANBI), Animal of the week
Human Ageing Genomic Resources: AnAge, The Animal Ageing and Longevity Database (Build 15)
U.S. Geological Survey, Nonindigenous Aquatic Species Database
Global Invasive Species Database (IUCN SSC Invasive Species Specialist Group)
|
| Activity pattern | Active by day. In the colder, temperate parts of South Africa it hibernates during cold weather in big rock cracks or burrows. When inactive it basks or rests on waterside vegetation, trees, logs and rocks, often in a prominent position, and it sometimes climbs trees to bask, feed or sleep.During activity periods it is mainly in the water, often hiding in dense vegetation in the shallows. Young often sleep together on branches at night. | Matches source · Animal Diversity Web (University of Michigan Museum of Zoology), South African National Biodiversity Institute (SANBI), Animal of the week, U.S. Geological Survey, Nonindigenous Aquatic Species Database, Global Invasive Species Database (IUCN SSC Invasive Species Specialist Group) — how we knowAnimal Diversity Web (University of Michigan Museum of Zoology)
South African National Biodiversity Institute (SANBI), Animal of the week
U.S. Geological Survey, Nonindigenous Aquatic Species Database
Global Invasive Species Database (IUCN SSC Invasive Species Specialist Group)
|
| Social structure | Usually solitary, with only occasional contact outside the mating season. Mating is promiscuous (polygynandrous), and males may reportedly fight in wrestling matches. Two may occasionally cooperate to raid a crocodile nest, one distracting the guarding female while the other takes the eggs.Young often stay in groups in which one may act as a temporary leader; they lick, groom and rub against one another and extend the dewlap. One account says the species hunts cooperatively. | Matches source · Animal Diversity Web (University of Michigan Museum of Zoology), South African National Biodiversity Institute (SANBI), Animal of the week, Global Invasive Species Database (IUCN SSC Invasive Species Specialist Group) — how we knowAnimal Diversity Web (University of Michigan Museum of Zoology)
South African National Biodiversity Institute (SANBI), Animal of the week
Global Invasive Species Database (IUCN SSC Invasive Species Specialist Group)
|
| Reproduction | Breeds once a year, mating and laying usually after the rains. Eggs are laid in holes in the ground, burrows or active termite mounds, 20 to 60 per clutch. Incubation is given as 6–9 months, apparently 6–10 months in the wild, or as possibly requiring 10 months. Matures at three to four years.sources disagreeThe rainy season varies regionally. In Mali and Chad, females mature at about 24 months (36 cm SVL) and about 50% of mature females breed each year. Captive eggs have hatched in as few as 129 days. Most authors say the young emerge unaided, but one author suggests females return to dig them out. In Cape Coral, Florida, breeding runs April–September, with hatchlings mainly February–April. Parthenogenesis may occur (2010 report). | Sources disagree · Animal Diversity Web (University of Michigan Museum of Zoology), South African National Biodiversity Institute (SANBI), Animal of the week, Global Invasive Species Database (IUCN SSC Invasive Species Specialist Group), U.S. Geological Survey, Nonindigenous Aquatic Species Database, The Reptile Database (Uetz et al.; new species and updates by the Zoological Museum Hamburg) — how we knowWhat each reading says
The laying season differs: one account places breeding in June–October with laying after the August–September rains, while another puts laying in Africa from August to early January. Incubation is given as 6 to 9 months, apparently 6 to 10 months in the wild, or possibly 10 months. Animal Diversity Web (University of Michigan Museum of Zoology)
South African National Biodiversity Institute (SANBI), Animal of the week
Global Invasive Species Database (IUCN SSC Invasive Species Specialist Group)
U.S. Geological Survey, Nonindigenous Aquatic Species Database
The Reptile Database (Uetz et al.; new species and updates by the Zoological Museum Hamburg)
|
| Human interaction | Much exploited in Africa for meat and skins, less so for the pet trade; overexploitation for skins has caused local extinctions. International trade is regulated under CITES Appendix II. Releases by reptile dealers and enthusiasts probably founded Florida's invasive populations.Its melted fat is locally believed to cure earache and protect against lightning, and it occasionally attacks chickens. In Florida it is a threat to native wildlife, including American crocodiles, sea turtles and burrowing owls, and could threaten waterbirds if it spreads into sensitive areas, and researchers are evaluating whether containment or eradication is possible. Its size and defensive disposition make it potentially dangerous to people and pets. | Matches source · Animal Diversity Web (University of Michigan Museum of Zoology), U.S. Geological Survey, Nonindigenous Aquatic Species Database, The Reptile Database (Uetz et al.; new species and updates by the Zoological Museum Hamburg), Global Invasive Species Database (IUCN SSC Invasive Species Specialist Group), University of Florida IFAS, Fort Lauderdale Research and Education Center (The Croc Docs), SUNY Open Access Repository (record of Dowell et al. 2016, Molecular Phylogenetics and Evolution 94: 591-604) — how we knowAnimal Diversity Web (University of Michigan Museum of Zoology)
U.S. Geological Survey, Nonindigenous Aquatic Species Database
The Reptile Database (Uetz et al.; new species and updates by the Zoological Museum Hamburg)
Global Invasive Species Database (IUCN SSC Invasive Species Specialist Group)
University of Florida IFAS, Fort Lauderdale Research and Education Center (The Croc Docs)
SUNY Open Access Repository (record of Dowell et al. 2016, Molecular Phylogenetics and Evolution 94: 591-604)
|
| Conservation status | Least Concern (LC), global assessment, 2021 | Matches source · IUCN Red List of Threatened Species — how we knowIUCN Red List of Threatened Species
|
References for the facts above
- ReferenceThe Reptile Database (Uetz et al.; new species and updates by the Zoological Museum Hamburg)Supports: identity and synonymy (status of V. ornatus and Tupinambis stellatus), identification (diagnosis), range (country list), body-size (diagnosis), reproduction (possible parthenogenesis), human-interaction (local extinction through skin exploitation). Retrieved 2026-10-20.Limitations: Taxonomic record; its detailed descriptions are withheld from the public page. The distribution is a country list without native or introduced tags apart from 'Introduced to USA (Florida)'. Its diagnosis (Lenz in Pianka et al. 2004) still contrasts V. niloticus with V. ornatus, which the record's own comment synonymizes. The query URL (species?genus=Varanus&species=niloticus) redirects to this record path.
- UniversityAnimal Diversity Web (University of Michigan Museum of Zoology)Supports: identification, range, habitat, diet, body-size, weight, lifespan, activity, social-structure, reproduction, human-interaction. Retrieved 2026-10-20.Limitations: Student-written account (Szczepaniuk 2011, last updated 2011-02-13). It treats the forest form as a separate species ('Varanus ornata'), unlike the taxonomic authority, so its figures may leave that form out. Its 2.4 m maximum does not name the measure. Not used: its statement that a 1985 Endangered Species Decree prohibits international trade (beside a CITES Appendix II listing) and its remarks on keeping the species as a pet.
- GovernmentU.S. Geological Survey, Nonindigenous Aquatic Species DatabaseSupports: identification, range (native and introduced), habitat, diet, body-size, weight, lifespan, activity, reproduction, human-interaction. Retrieved 2026-10-20.Limitations: Florida-focused nonindigenous-species profile by L. A. Somma (revision date 4/22/2019), marked preliminary or provisional; its occurrence table was updated 10/20/2026. Its lifespan statement does not say whether wild or captive. Not used: its anecdote about a deceased pet owner, its quotation about pet cats, its remarks on suitability for captivity, and its occurrence table (records from AZ, CA, GA, PR, TX and VA; populations may not be present).
- ReferenceGlobal Invasive Species Database (IUCN SSC Invasive Species Specialist Group)Supports: habitat (native range and Florida), diet, body-size, weight, lifespan, activity, social-structure, reproduction (Africa, Mali and Chad, Florida), human-interaction. Retrieved 2026-10-20.Limitations: Profile published 2010-07-20 and compiled from secondary citations (largely Enge et al. 2004 and Campbell 2005); its identification text is quoted from the USGS profile. It calls V. n. ornatus a distinct species, unlike the authority. Its 8.1 kg maximum disagrees with its own Florida males of over 12 kg. Not used: a toxicant dosing trial (safety rule), Florida possession rules effective 2008 (current FWC rules could not be read) and alien records from Taiwan (context not given).
- GovernmentSouth African National Biodiversity Institute (SANBI), Animal of the weekSupports: identification, range, habitat, diet, body-size, lifespan, activity, social-structure, reproduction. Retrieved 2026-10-20.Limitations: Popular page by N. Dlamini, KwaZulu-Natal National Botanical Garden (January 2016; posted 20/05/2018), with a reference list but no in-text citations. Several passages repeat ADW word for word (solitary behavior, mating system, breeding season, captive lifespan, pet sentence), so it is not independent of ADW on those points. It gives the authorship as (Linnaeus, 1758) and says V. ornatus was raised to species in 1997, unlike the authority. Its remarks on holding the animal and on pet keeping were not used.
- UniversityUniversity of Florida IFAS, Fort Lauderdale Research and Education Center (The Croc Docs)Supports: range (native range; Florida breeding populations), human-interaction (threats to native wildlife; containment and eradication research). Retrieved 2026-10-20.Limitations: Undated research-project page without in-text references; Palm Beach County focus. Its 'more than six feet' length was not used as a size figure.
- UniversitySUNY Open Access Repository (record of Dowell et al. 2016, Royal Society Open Science 3: 150619)Supports: range (Florida breeding populations and their West African origin). Retrieved 2026-10-20.Limitations: Abstract only; the article page at royalsocietypublishing.org returned HTTP 403.
- UniversitySUNY Open Access Repository (record of Dowell et al. 2016, Molecular Phylogenetics and Evolution 94: 591-604)Supports: identity and range (western, northern and southern lineages; the western lineage matched to Tupinambis stellatus), human-interaction (exploitation for bushmeat, leather and the pet trade). Retrieved 2026-10-20.Limitations: Abstract only. The Reptile Database cites this work as Dowell et al. (2015) and follows its synonymy of V. ornatus, but has not adopted a separate western species.
- ReferenceHuman Ageing Genomic Resources: AnAge, The Animal Ageing and Longevity Database (Build 15)Supports: lifespan (captive maximum), weight (average adult mass). Retrieved 2026-10-20.Limitations: The 14.6-year captive maximum cites a secondary web page (ref. 451, 'Frank & Kate's Web Page'); sample size Medium, data quality Acceptable. The life-history averages (maturity 1,278 days; adult weight 2,827 g) carry no per-value reference; the maturity figure was not used.
- ReferenceIUCN Red List of Threatened SpeciesSupports: The global Red List category and the year of the assessment. Retrieved 2026-10-20.Limitations: Read from the Red List export IUCN publishes to GBIF; iucnredlist.org itself does not answer automated reads. Categories are reassessed over time.
Frequently Asked Questions — Nile Monitor
How big do Nile monitors get?
One account says adults grow to about 100–140 cm in total length, with a tail much longer than the body. The maximum is given as about 200 cm, 2.4 m, 243 cm or more than 2.42 m, depending on the account, and the species is described as Africa's longest lizard.
What do Nile monitors eat?
Almost any animal they can overpower — snails and other mollusks, crabs, insects, fish, frogs, lizards, snakes, turtles, birds and their eggs, small mammals and young crocodiles — as well as carrion. They have been known to raid crocodile nests for eggs.
Are Nile monitors invasive in Florida?
Yes. Breeding populations are established in southern Florida, probably founded by releases from reptile dealers and enthusiasts, and the lizards are a threat to native wildlife such as American crocodiles, sea turtles and burrowing owls.
How long do Nile monitors live?
In captivity the expected lifespan is reported as 10–20 years, but the longest recorded is 14.6 years. Where the setting is not stated, accounts say they may live more than 10–15 years, or as long as 10 to 15 years.
Sources and further reading
Authoritative wildlife references used for general educational context. Conservation status should always be verified against current IUCN Red List data. External links open in a new tab.
- ReferenceThe Reptile Database (Uetz et al.; new species and updates by the Zoological Museum Hamburg) — Varanus niloticus taxonomic record — identity and synonymy (status of V. ornatus and Tupinambis stellatus), identification (diagnosis), range (country list), body-size (diagnosis), reproduction (possible parthenogenesis), human-interaction (local extinction through skin exploitation)
- UniversityAnimal Diversity Web (University of Michigan Museum of Zoology) — Varanus niloticus (Nile monitor) species account — identification, range, habitat, diet, body-size, weight, lifespan, activity, social-structure, reproduction, human-interaction
- GovernmentU.S. Geological Survey, Nonindigenous Aquatic Species Database — Nile monitor, Nonindigenous Aquatic Species fact sheet — identification, range (native and introduced), habitat, diet, body-size, weight, lifespan, activity, reproduction, human-interaction
- ReferenceGlobal Invasive Species Database (IUCN SSC Invasive Species Specialist Group) — Varanus niloticus, Global Invasive Species Database — habitat (native range and Florida), diet, body-size, weight, lifespan, activity, social-structure, reproduction (Africa, Mali and Chad, Florida), human-interaction
- GovernmentSouth African National Biodiversity Institute (SANBI), Animal of the week — Animal of the week: Nile monitor — identification, range, habitat, diet, body-size, lifespan, activity, social-structure, reproduction
- UniversityUniversity of Florida IFAS, Fort Lauderdale Research and Education Center (The Croc Docs) — Invasive Nile monitors in Florida (research project) — range (native range; Florida breeding populations), human-interaction (threats to native wildlife; containment and eradication research)
- UniversitySUNY Open Access Repository (record of Dowell et al. 2016, Royal Society Open Science 3: 150619) — Dowell et al. 2016, origins of Florida's Nile monitors (repository record) — range (Florida breeding populations and their West African origin)
- UniversitySUNY Open Access Repository (record of Dowell et al. 2016, Molecular Phylogenetics and Evolution 94: 591-604) — Dowell et al. 2016, genetic lineages of the Nile monitor (repository record) — identity and range (western, northern and southern lineages; the western lineage matched to Tupinambis stellatus), human-interaction (exploitation for bushmeat, leather and the pet trade)
- ReferenceHuman Ageing Genomic Resources: AnAge, The Animal Ageing and Longevity Database (Build 15) — Varanus niloticus longevity entry — lifespan (captive maximum), weight (average adult mass)
- ReferenceIUCN Red List — Varanus niloticus assessment — The global Red List category and the year of the assessment