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Reptiles · Papua

Crocodile monitor

The crocodile monitor (Varanus salvadorii) is a large tree-climbing monitor lizard found only on New Guinea, with a very long tail and serrated teeth.

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Photograph of Crocodile monitor (Varanus salvadorii).
Crocodile monitor at Cincinnati Zoo, United States (captive animal). Ltshears, Wikimedia Commons · CC BY 3.0 · Image cropped for layout.

Quick answer

IUCN status: Least Concern

Crocodile monitor at a glance

The crocodile monitor (Varanus salvadorii) is a reptile in the family Varanidae. Range in Indonesia: Papua (Indonesian New Guinea). Diet: birds, small mammals, fish, eggs and carrion; a carnivore. IUCN Red List status: Least Concern.

Quick facts: Crocodile monitor
Scientific nameVaranus salvadorii
Indonesian nameBiawak Papua
GroupReptiles
FamilyVaranidae
Range in IndonesiaPapua (Indonesian New Guinea)
Linked habitatsTropical Rainforests, Mangroves
DietBirds, small mammals, fish, eggs and carrion
Range in IndonesiaLowland forest and mangroves in Papua
Key featureTail up to two-thirds of total length
Other namesPapuan monitor, Salvadori's monitor
Risk to peopleBite and tail lash can cause serious injury
IUCN statusLeast Concern · IUCN Red List (via GBIF) · checked 1 October 2026
Lifespan in captivityAbout 10 years, up to 20 years · Smithsonian's National Zoo — Crocodile monitor
Diet typeCarnivore (meat-eater) — predator (birds, eggs, small mammals) and scavenger · Animal Diversity Web
ReproductionLaying eggs (oviparous) · Reptile Database
Venom or poisonMildly venomous (weak venom for people) · Koludarov et al. 2017, Enter the Dragon: The Dynamic and Multifunctional Evolution of Anguimorpha Lizard Venoms (Toxins)
ActiveDiurnal (active by day) · ReptTraits v1-2 (Oskyrko et al. 2024, Scientific Data 11:243), column 'Active time'
In this guide (12)
About this guideCompiled and checked against the listed sources; not yet reviewed by a specialist.

What is the crocodile monitor?

The crocodile monitor (Varanus salvadorii) is a large tree-climbing monitor lizard from New Guinea and one of the longest lizards in the world. Smithsonian's National Zoo says it can exceed 2.4 metres in total length and weigh up to 20 kg, with the tail making up to two-thirds of that length. It is blackish-green with bright yellow spots and stripes. Its teeth are flat, very sharp and serrated.

The Reptile Database places it in the subgenus Papusaurus. It is named after the ornithologist Tommaso Salvadori, and its type specimen came from Dorei, today's Manokwari.

Evidence: Smithsonian's National Zoo and Conservation Biology Institute — Crocodile monitor ↗ · The Reptile Database — Varanus salvadorii ↗ · Journal of Threatened Taxa — Range extension and new ecoregion records of the crocodile monitor Varanus salvadorii in Papua New Guinea (2022) ↗

Where does the crocodile monitor live?

The crocodile monitor lives only on New Guinea, in both Indonesian Papua and Papua New Guinea. Smithsonian's National Zoo describes its populations as fragmented and records it in Papua and West Papua. It lives in lowland rainforest, floodplain forest, mangrove swamps and riverside woodland that are undisturbed by people.

It is usually found from sea level to about 740 metres, but camera traps in the Torricelli Mountains of Papua New Guinea recorded one at 1,500 metres. It spends much of its time in trees but also comes down to the ground near water.

Evidence: Smithsonian's National Zoo and Conservation Biology Institute — Crocodile monitor ↗ · Animal Diversity Web — Varanus salvadorii (crocodile monitor) ↗ · Journal of Threatened Taxa — Range extension and new ecoregion records of the crocodile monitor Varanus salvadorii in Papua New Guinea (2022) ↗

What does the crocodile monitor eat?

The crocodile monitor is a carnivore that preys on birds, mammals, fish and other small animals. Smithsonian's National Zoo says its wild diet is poorly known but is thought to include birds, mammals and fish, and occasionally eggs, small reptiles and carrion. Animal Diversity Web adds rodents, amphibians and insects.

Long, sharp teeth and powerful jaws seize the prey, which is swallowed whole. As an apex predator in New Guinea's forests, it helps keep populations of smaller animals in check.

Evidence: Smithsonian's National Zoo and Conservation Biology Institute — Crocodile monitor ↗ · Animal Diversity Web — Varanus salvadorii (crocodile monitor) ↗ · Journal of Threatened Taxa — Range extension and new ecoregion records of the crocodile monitor Varanus salvadorii in Papua New Guinea (2022) ↗

How does the crocodile monitor behave?

The crocodile monitor is an agile climber that usually lives alone. Animal Diversity Web says it basks during the day and uses its long tail for balance when jumping between branches. Smithsonian's National Zoo notes it is aggressive towards other individuals, especially those of the same sex.

Its breeding in the wild is almost unknown. In captivity, females lay 4–12 eggs four to six weeks after mating, up to three times a year, and the eggs incubate for five to eight months. Hatchlings measure about 35–41 cm.

Evidence: Animal Diversity Web — Varanus salvadorii (crocodile monitor) ↗ · Smithsonian's National Zoo and Conservation Biology Institute — Crocodile monitor ↗

Is the crocodile monitor dangerous?

The crocodile monitor can be dangerous if disturbed, because its bite and tail lash can cause serious injury. Animal Diversity Web notes it can do severe damage to people who disturb it, and that attacks on livestock are not uncommon. Smithsonian's National Zoo says it uses its tail like a whip in defence, and its sharp, serrated teeth for defence and catching prey.

Do not approach, catch, handle or kill it. Keep a safe distance and ask trained officers for help. If bitten, seek medical care at a health facility immediately.

Evidence: Animal Diversity Web — Varanus salvadorii (crocodile monitor) ↗ · Smithsonian's National Zoo and Conservation Biology Institute — Crocodile monitor ↗

What threatens the crocodile monitor, and how can it be protected?

The biggest threat to the crocodile monitor is forest loss from logging and clearing for agriculture, because it avoids areas disturbed by people. Smithsonian's National Zoo also lists hunting for skin and meat, and notes that the species has recently entered the pet trade. According to Animal Diversity Web, its skin has traditionally been used for clothing and ritual drum heads.

The IUCN rates it Least Concern, but its population is thought to be declining, and international trade is controlled under CITES Appendix II. Do not buy wild-caught monitors, and support the protection of Papua's lowland forests.

Evidence: Smithsonian's National Zoo and Conservation Biology Institute — Crocodile monitor ↗ · Animal Diversity Web — Varanus salvadorii (crocodile monitor) ↗

Explore related habitats

These habitat relationships are supported by species sources in this guide. This is not a complete range map.

Scientific classification of the Crocodile monitor

Scientific classification from kingdom to species
KingdomAnimalia
PhylumChordata
ClassReptilia
OrderSquamata
FamilyVaranidae
GenusVaranus
SpeciesVaranus salvadorii

Source: GBIF Backbone Taxonomy, adjusted to the ranks commonly used in school biology (for example class Reptilia).

Common questions about the crocodile monitor

What is the scientific name of the crocodile monitor?

The scientific name of the crocodile monitor is Varanus salvadorii, in the family Varanidae. In Indonesian it is called Biawak Papua.

What kind of animal is the crocodile monitor?

The crocodile monitor is a reptile in the family Varanidae. By diet it is a carnivore (meat-eater): a predator (birds, eggs, small mammals) and scavenger.

Where does the crocodile monitor live in Indonesia?

In Indonesia, this guide records the crocodile monitor in: Papua (Indonesian New Guinea).

Source-supported habitats: Tropical Rainforests, Mangroves.

What does the crocodile monitor eat?

Diet of the crocodile monitor: birds, small mammals, fish, eggs and carrion. That makes it a carnivore (meat-eater). Source: Animal Diversity Web.

How does the crocodile monitor reproduce?

The crocodile monitor reproduces by laying eggs (oviparous). Source: Reptile Database.

Is the crocodile monitor venomous?

Yes. The crocodile monitor is mildly venomous (weak venom for people). Its venom has been reported to cause prolonged bleeding after bites to people; the main danger remains the deep bite wound. Source: Koludarov et al. 2017, Enter the Dragon: The Dynamic and Multifunctional Evolution of Anguimorpha Lizard Venoms (Toxins).

Do not catch, handle or disturb wild animals. If bitten, stung or exposed to its toxins, go to the nearest health facility straight away.

Is the crocodile monitor nocturnal?

The cited source records the crocodile monitor as diurnal (active by day). Source: ReptTraits v1-2 (Oskyrko et al. 2024, Scientific Data 11:243), column 'Active time'.

See also the list of nocturnal and diurnal animals in Indonesia.

What are the main features of the crocodile monitor?

Key features of the crocodile monitor, from this guide’s sources: Key feature: tail up to two-thirds of total length.

Is the crocodile monitor dangerous to people?

Bite and tail lash can cause serious injury.

Do not approach, catch or handle wild animals. If you are injured or bitten, get medical care at a health facility straight away.

What is the scientific classification of the crocodile monitor?

Scientific classification of the crocodile monitor: kingdom Animalia, phylum Chordata, class Reptilia, order Squamata, family Varanidae, genus Varanus, species Varanus salvadorii.

Source: GBIF Backbone Taxonomy, adjusted to the ranks commonly used in school biology.

Is the crocodile monitor endangered?

No, according to the global IUCN assessment. On the IUCN Red List, the crocodile monitor is listed as Least Concern: it does not qualify for a threatened category or for Near Threatened in the global assessment. Source: IUCN Red List (via GBIF), checked 1 October 2026.

This global category is separate from legal protection in Indonesia. To check whether the crocodile monitor is a protected species, consult the current national list of protected species or contact the local BKSDA (natural resources conservation office).

Sources & references

  1. The Reptile Database — Varanus salvadorii ↗
  2. Animal Diversity Web — Varanus salvadorii (crocodile monitor) ↗
  3. Smithsonian's National Zoo and Conservation Biology Institute — Crocodile monitor ↗
  4. Journal of Threatened Taxa — Range extension and new ecoregion records of the crocodile monitor Varanus salvadorii in Papua New Guinea (2022) ↗
  5. Wikipedia bahasa Indonesia — Biawak Papua ↗
  6. ReptTraits v1-2 (Oskyrko et al. 2024, Scientific Data 11:243), column 'Active time' ↗
  7. Koludarov et al. 2017, Enter the Dragon: The Dynamic and Multifunctional Evolution of Anguimorpha Lizard Venoms (Toxins) ↗
  8. GBIF Backbone Taxonomy (GBIF) ↗
  9. IUCN Red List of Threatened Species, version 2026-1, via GBIF (CC BY 4.0) ↗

References can change. Check dates and context in the original source. How we use sources and data →

Further reading

Monitor lizard: facts, threats and conservation ↗ — World Animal Rescue Network. A broader overview that covers this animal.

Related site: PanduanHewan’s founder is also a director of World Animal Rescue Network.

Cite this page

Credit PanduanHewan when referring to this page. Check the original evidence sources before reusing a claim.

PanduanHewan. Crocodile monitor (Varanus salvadorii). Last substantive update: 1 October 2026. https://panduanhewan.org/en/species/crocodile-monitor/