Crocodile Monitor Care Sheet

Scientific Facts

Common Name: Crocodile Monitor, Papua monitor, Salvadori’s monitor
Scientific Name: Varanuss salvadorii
Life Span: 10 to 15 years
Size: 244 cm
Habitat: Mangrove swamps and coastal rainforests
Country of Origin: New Guinea

Physical Description

Image Source

The Varanus salvadorii or crocodile monitor is a lizard that is endemic to the rainforests of New Guinea. It is also known as Salvadori’s monitor, artellia, and Papua monitor. This is the largest lizard known in Papua New Guinea and is also one of the longest lizards known to man at 8 feet long.

The tail of the crocodile monitor is very long, and no other specimens have exceeded its length. The Komodo dragon has a smaller tail compared to the crocodile monitor.

The crocodile monitor is arboreal animals. It has a dark-green body with yellow bands and marks. This snake has a blunt snout but has a very long tail. You’ll find crocodile monitors in mangrove swamps and in coastal rainforests, usually along the southeastern part of the tropical island.

The crocodile monitor will eat birds, eggs, small mammals, and carrion. The teeth of a crocodile monitor area adapted to the animal’s routine. It can snatch moving prey fast. And just like other monitor lizards, the crocodile monitor has better stamina. But when it comes to reproduction, very little is known about it.  Breeders also have very little luck breeding this in captivity.

Crocodile monitor habitats are in danger due to deforestation and poaching. This animal is protected by the CITES agreement; therefore, it is illegal to purchase, sell, and trade this lizard. Local tribesmen hunt and kill this animal for their skin. These lizards may also be skinned alive to make drums. Locals call the crocodile monitor as an “evil spirit” that climbs trees, breathes fire, kills humans, and walks upright. The name crocodile monitor stuck as tribesmen believed that this lizard warns them if crocodiles are nearby.


The most impressive feature of the crocodile monitor is its snout. This makes this monitor very different from other monitors in New Guinea. The tail is very long, about twice as long as the snout to vent length.

The teeth of this lizard are long, sharp, and straight. It has very prominent claws that are curved. You can’t tell the male from the female crocodile lizard. This lizard has mammal-like abilities; a pressure gular pump located along the throat improves lung ventilation. Most lizards are unable to breathe well while running because of the Carrier’s constraint the pump of the monitor lizards allows them to deal with the use of one lung at a time. This is an adaptive mechanism as the lungs are compressed during running. The gular pump’s use is similar to the diaphragm in mammals, which improves ventilation in the lung no matter what the mammal is doing. The crocodile monitor is known as the species that has achieved the best running endurance due to the presence of the gular pump.


The evolutionary history of the crocodile monitor started with the Varanus genus lizards. These lizards originated in Asia for around 40 million years. A tectonic connection between Southeast Asia and Australia allowed the Varanids to spread to Indonesia.

According to mitochondrial DNA and other analyses and studies of the species, it was found that the crocodile monitor is a member of a species of lizard which lace monitors and the Komodo dragons belong.

But the distance of their areas of origin shed some doubt on this theory, but researchers said that it was possible that island hopping may have happened. Also, the similarities with the V. salvadorii and the V. varius may due to convergent evolution. 

Meanwhile, Eric Piankaa placed the crocodile monitor in a larger clade of large monitor lizards, including other species like the Komodo dragon, lace monitor, perentie, Argus monitor, and sand goanna.

The crocodile monitor is known as the largest of all the seven different species of monitors found in New Guinea. V. salvadorii is found in both Papua New Guinea and the Indonesian province of West Papua. This monitor lives in the high and the low areas of the lowland rainforests as well as the coastal mangroves and swamps. There are crocodile monitor sightings during floods during the rainy season in the country.

As of the moment, there is no data regarding the range of the crocodile monitor. Because of the remote and inaccessibility of its habitat has made it impossible to monitor. 


The crocodile monitor is protected by CITES Appendix II, which means exportation and trade should be done under an exportation permit for international trade. However, this lizard is not included in the IUCN Red List of endangered species. This lizard faces threats from poaching and deforestation since this is hunted and skinned by local folks. In 2008, 52 crocodile monitors were kept in 17 zoos and parks in the United States. Still, it is unknown as to how many monitors are kept in private homes. 

Life Span

Only a few people had the rare opportunity to raise this lizard in captivity compared to juvenile and adult wild-caught monitors. Captive specimens of crocodile monitors can live around 10, but some large captive monitor lizards can live 15 years or more.

The usual cause of death in captive populations include complications from health conditions like egg impaction, infection of bite wounds, stomach abscesses, mouth abscesses, liver lesions, brain lesions, and other conditions., 

The Crocodile Monitor has three life stages, just like other lizard species:


A Crocodile Monitor will lay eggs in clutches, and these eggs will hatch with hatchlings around 18 inches long. Hatchlings are small, but the facial features and body are already the same as adults. Hatchlings are also ready to eat anything offered to them. These snakes are also more colorful than their parents are.


During the juvenile stage, both male and female Crocodile Monitors are at the same size, color, and shape. Juveniles have slightly brighter markings than adults.


Adult Crocodile Monitors eventually become mature and ready to mate. The colors are darker, and the body is longer, and the tail is thicker as well.

Eating Habits

Crocodile monitors have teeth that are very different from other monitor lizards. These are blunt, facing rearward, and are described like wooden pegs. The lizard’s upper teeth are very long and fang-like and are set in a vertical manner in its jawbone. This allows the lizard to capture fast-moving prey like bats, birds, and rodents. The lower teeth have a fleshy sheath.

The crocodile monitor is the top predator in New Guinea, and locals say that it can even feed on dogs. It will take its prey into the forest canopy so it can consume it in peace. There are still people who care for crocodile monitors in captivity like in parks and zoos. Captive crocodile monitors can eat rodents, chickens, fish, frogs, and dog food.

Experts have seen the crocodile monitor hunting prey, but the manner how it hunts is quite unique from other monitor lizards. Rather than taking down the prey from the back, it will stalk its prey and find out where it will run or turn and meets it head-on.  


This lizard needs water to drink. If you are keeping one as a specimen, a shallow bowl of water is recommended. The water dish should be large and heavy so it won’t get knocked down by the monitor. It also has a long tongue that can lick the vapor off plants, walls, and floors. You can spray water inside its enclosure at least twice or thrice a day.  

Development, Reproduction, and Breeding

The development and reproduction of the crocodile monitor have only been observed while in captivity. There is no information about its development in the wild. The female deposits up to 12 eggs around October to January. The eggs have remarkable differences when it comes to dimensions. It is unknown as to why these differences happened.

Most clutches that have been laid while the lizard is in captivity have become infertile, and as far as experts say, only four successful breeding has been documented. And like most monitors, the hatchling is as colorful compared to their parents.

Common Health Problems

Here are the common problems that Crocodile Monitors experience:


Reptiles such as lizards come with parasites that at first may have no effect on their health. But when lizard feels stressed or has any immune system condition, these parasites can cause life-threatening diseases.

These parasites can multiply and affect the lizard’s health. Parasites may also affect other animals and humans. You can stop parasites and infections from spreading by keeping a new lizard under quarantine. A new lizard is the usual cause of parasites, and placing it on quarantine will reduce parasites in the enclosure or tank.

Check for signs and symptoms of parasitic infections such as a smelly or runny poop, weight loss, a large abdomen, anorexia, and a lack of energy.

According to experts, wild-caught specimens are infected with mite ova, flagellates, cestodes, strongyles, and oxyurids. But with good husbandry, access to natural sunlight, and a good diet, these lizards may not be affected at all.

Incomplete Shedding

Monitor the lizard for signs of incomplete shedding difficulty like having skin flakes, skin clinging on the tail or the eyes, and restlessness. Any stuck skin should be removed as soon as possible. And for any severe shedding worries, consult a vet. A vet can remove stuck skin and will treat wounds because of incomplete shedding.

Metabolic Bone Disease

MBD is a very common condition in reptiles and other animals that lay eggs. This is due to the lack of calcium in bones, and symptoms may happen over time and may show acute symptoms such as bowed legs, a rubbery jaw, and kinks along the spine.

Also, females that hatch eggs like crocodile monitor females also need calcium in their diets.

MBD can be reversed by consuming vitamin D3 and calcium. Use calcium supplements and proper UV lighting to enhance the D3 levels in the body.

Bleeding Gums and Imbedded Teeth

The gums of crocodile monitors are prone to bleeding, and it’s unclear as to this is a natural result of biting on food or prey, cutting new teeth, or as a fear response. A crocodile monitor also suffers from embedded teeth in the gums, which result in infection, and this needs treatment ASAP.


Crocodile monitors enjoy a lot of time basking, and this may be the reason why this lizard suffers from cataracts. Some lizards have severe cataracts, which may lead to blindness.

Preventing Illness

The most important way to prevent illness is to keep enclosure tank temperature and humidity at the ideal levels. This is needed by lizards even something as large and as ferocious as the crocodile monitor.

Place a bowl of water in the tank because this will become your monitor’s water dish. It can also enhance humidity and to enhance shedding. You must keep your tank clean because a dirty tank can lead to the growth of bacteria, which can affect the health of your lizard. Also, a good cleaning product is important. Don’t use products with residue and toxins that may harm your lizard.

Provide the best food. When it comes to using rodents and lizards, these have to be organic. Never capture in your yard because these have toxins coming from pesticides, which can affect the health of your lizard.

Always quarantine new lizards. These new pets may have pests, mites, and parasites; therefore, you must monitor its health before you introduce it to other lizards. How long the monitor remains in the quarantine may depend on you. You can wait till a week or a month to quarantine a lizard as large a monitor lizard.


The following are common behaviors of Crocodile Monitors:

Arboreal Lizards

The crocodile monitor is a highly arboreal lizard that can hang on to tree branches using its rear legs. It may also use its tail as a prehensile grip. So if ever you’re in New Guinea and you chance upon a crocodile monitor, don’t run for the trees because it can easily climb up trees and hang on to branches.

Strong Tails

These lizards have very strong tails, and this has many uses. The tail can be used as a counterbalance when it leaps from branch to branch of the tree. It is useful as a defense. There are reports that captive specimens using their tails to lash out on their keepers. The keepers suffered severe wounds and bruises afterward.

Aggressive and Unpredictability

This lizard is known for its extreme aggression and sometimes unpredictable behavior, which is not a good behavior for kept lizards. It is not a pet and should not be placed in a home or property that’s not secure.

Resting on Trees

Aside from wandering around looking for prey, this lizard also loves to rest on trees. This can also remain on the ground and even submerged in water. The crocodile monitor is actually a versatile lizard since it can rest on tree branches, on the ground, and in water as well. And since it does not have any predator, it remains supreme in looking for prey in water, land, and in forest canopies.

Can Rise on Hind Legs

Another impressive thing about this monitor lizard is that it can stand on their hind legs to monitor their surroundings. The crocodile lizard looks like it is patrolling the area, and experts say that it actually is, especially when it is planning its next move.

“Warning Posture”

The so-called “warning posture” is something that locals dread. This large lizard may be seen standing up and carrying its tail all rolled up behind their backs. It is a weird sight to see, and up till now, it remains a mystery as to the real reason why the crocodile monitor does this.

An expert on reptile behavior said that this warning posture could mean that the lizard is looking for its prey and does not want anyone knowing that it is nearby. This is the reason why it holds its tail from behind.

Avoids Human Contact

In captivity or in the wild, the crocodile monitor avoids any form of human contact. If you find a crocodile monitor in captivity, chances are it is rarely petted or handled by its owner. It is also possible that a monitor was purchased as a juvenile lizard and was thrown away by its owner after growing its full size.

Dangerous Bite

The most dangerous part of crossing paths with a crocodile lizard is that it has a very dangerous bite. According to reports, the bite of this monitor can cause an infection, just like the bite of a Komodo dragon. It is said that one fatality was reported in the 1980s, and it was a Papuan woman who was bitten and died because of an infection in the wound.

The reason why the bite of a monitor is dangerous is that its saliva and mouth contain bacteria that can cause inflammation and, eventually, an infection. The only way to save a person bitten by the monitor is to clean the wound and have it checked by a doctor.

Weird Gait

This lizard has a weird running gait that compresses its lungs. But its body compensates by the presence of the gular pump, which allows the lizard to enhance its ventilation. Experts actually studied the idea of breathing using the gular pump. It is said that the crocodile monitor is the species of monitor lizard that has achieved the best running endurance. The researchers said that gular breathing is an adaptation of an evolutionary development that covers the effects of the Carrier’s constraint.


Crocodile monitors must not be kept together in one cage or enclosure, especially males or females, or of the same sex. If you want to keep a pair, set up a cage where the two can meet and interact safely. Closely monitor their behavior before totally placing the two in one cage.

May Pair Bond

There are reports that two crocodile monitors may pair bonds in captivity. But it’s still better if you introduce the two lizards slowly to avoid aggression.


Shedding should be complete and in one go from head to tail. But some lizards may have problems with incomplete shedding. In incomplete shedding, parts of the tail, limbs like the hands and feet and eyes, shed in flakes. Also, the skin may be hard to remove in some areas of the body. Mostly, incomplete shedding can be due to humidity problems and other metabolic conditions.

To treat incomplete shedding and for the monitor lizard to shed completely, you must improve humidity levels inside its cage or enclosure.  Take note that shedding may happen in juveniles and less frequently when it comes to adults. Shedding is stressful, so leave the lizard alone. Take the lizard to the vet for any problems with shedding.


The ideal enclosure is a huge one, preferably a large metal cage. This is only for one lizard, but during breeding time, place one male to one female to ensure success in mating.

Place the metal enclosure or cage under lock and key to prevent this lizard from escaping and from other pets entering the tank. You should place the lizard tank in an outdoor environment

In the wild, it’s a very different thing for Crocodile Monitors. These animals can be seen walking proudly along with sunny areas or soaking under rocks. Usually, these lizards are solitary. It may come across another monitor lizard, but when you look closer, there is almost no interaction that happens between each individual lizard.

Lighting, Humidity, and Temperature

The Crocodile Monitor may be kept indoors or outdoors. Outdoors, it will simply be contented with basking under the warm sun. Indoors, it’s a different story.

It needs a good lighting system. A basking light is the best choice for a small tank or enclosure. High-powered lamps are perfect for a large tank. Place your lizard in a minimum of 12 hours of light daily to mimic daylight. This is the best amount of light to enhance the health and tank environment.

Use an under-cage heating pad to maintain the tank temperature. This will keep the tank interiors at 110 to 120 degrees Fahrenheit in the morning and 100 degrees at night. One way to enhance humidity is to apply a spray of water several times a day to ensure that the tank remains humid.

Use a humidifier for a large area and for more accurate humidity readings. A bowl of water is a good way to enhance humidity. Tie the bowl of water to the tank avoid being knocked over. Keep your lizard’s water clean and fresh day after day. 

Tank Bedding and Accessories

Crocodile Monitors should have dens similar to where it resides in the wild. A hollow log will do. Cut this in the proper size and place this inside the enclosure. You can have a simple or an elaborate enclosure or tank; just remember that an elaborate tank is a challenge to clean, and it is also hard to see your pet as well.

The accessories must be safe, must have no pointed edges, which can injure the crocodile monitor. Your pet’s health is foremost, so don’t place dangerous accessories. Create one den near the heat source and one farther away in case your lizard wants a cooler area where it can sleep.  For the bedding or substrate, use paper, newspaper, butcher, or packing paper for young lizards.


Maintain your lizard’s cage with natural and safe solutions. You can use homemade cleaners or commercially available cleaners. Homemade enclosure cleaners like baking soda, lemon, or vinegar are effective and natural.

Another good technique is to use dishwashing soap, bleach, and water. Use a large brush with long handles to scrub the enclosure thoroughly. Rinse everything before you place the lizard back inside the tank. Baking soda and lemon can clean the tank and deodorize it.

For chemical cleaners, follow the instructions on the label to the T. Rinse well with running water when you’re done. Use paper towels or a soft clean towel to dry the walls, flooring, and tank accessories. You must clean filters, humidifiers, and fans regularly to efficiently maintain your lizard’s tank.

Availability – Where to Get One?

You can get a baby Crocodile Monitor from a pet store or an online reptile trade shop, but it’s not a guarantee that you’ll find one ready to ship because it’s hard to look for good specimens.

The price for a regular Crocodile Monitor depends on the trader. Usually, it depends on the size, color, gender, and age. The cost of shipment and delivery will affect the cost of a Crocodile Monitor. And considering that it’s hard to breed this in captivity, most traders may poach on baby crocodile monitor in the wild.

How to Care for a Crocodile Monitor

Crocodile Monitors should be cared for with the following techniques:

  • Keep the reptile tank humid to avoid illnesses, enhance shedding, and to keep this huge lizard healthy. For you have a bigger tank enclosure, use a humidifier to control humidity. Correct lighting also enhances humidity, so apply proper lighting conditions inside the lizard’s enclosure.
  • Install the tank in a quiet area when the lizard is asleep and especially during nighttime. Feed your lizard when it’s awake and energetic. Because lizards are diurnal, monitor your lizard’s preferred time to eat and use this as your daily feeding schedule.
  • For small lizards or juvenile lizards, change your substrate frequently to prevent mold, bacteria, and parasite growth. You can use all kinds of soft soil for a substrate to mimic the natural environment of this lizard.
  • Avoid overcrowding, so use a larger cage or enclosure. As much as possible, place one lizard in one tank to prevent crowding and from aggression. Use smaller tanks for breeding.
  • You must always change the water inside the bowl. Keep this fresh and clean. Never remove this inside the tank to enhance humidity.
  • Take your pet to a reptile specialist or an exotics vet regularly, especially when you notice poor appetite, sick, wounded, or lethargic. 
  • Some lizards carry parasites and may still appear healthy. To completely avoid infection, wash your hands before and after handling your pet.
  • Use substrates like peat moss, gravel, natural earth, mulch, and all kinds of wood shavings and tree bark. The substrate should be able to retain moisture without creating an environment that can harbor mold and bacteria. A soft, moist substrate also acts as a soft cushion where the lizard can land on.
  • A large outdoor cage is probably the best captive enclosure for this lizard. It should be large, open, yet secure. The enclosure should also be clean and sanitized to ensure the health of your pet lizard.
  • When handling this lizard, use a large leash and a collar. Walk it as if you would a dog. Never let it loose in your yard because this can escape easily.
  • Also, before thinking of taking a crocodile monitor in your home, find out if this is legal to own and keep in your area, country, or state. If you are unsure, contact the animal regulatory office in your country or state.  
  • Finally, consult a reptile specialist regarding your pet’s diet. A large part of a crocodile monitor’s life is spent in hunting prey. You must understand your lizard’s needs and provide the right food at the right time.

FAQ Section

Can you have a crocodile monitor as a pet?

Yes, some people take the crocodile monitor as pets. You can spot breeders taking care of this large lizard at home in enclosures that are customized, pre-ordered. Usually, crocodile monitor breeders keep more than on lizards in the hopes of breeding success.

Can you buy a crocodile monitor online?

Yes, you can buy one online, but it can take time to confirm your order since this lizard is hard to breed. Online ordering also means your snake will likely arrive many weeks from the date you ordered it unlike buying this snake from a local trader or pet owner you don’t have to wait.

How do you feed a crocodile monitor?

You feed this snake with size-appropriate food. You can place it inside the dish inside the tank or place food directly in the tank. Your pet lizard will gladly eat food from the dish or from the different areas of the tank.                                                                                                                                                                                                                                                                                                                                                                                

Do you pet a crocodile monitor?

Yes, you can have this as a pet. You must train your pets for better handling early on. Petting on the head of a lizard means that it is willing to submit to your handling.

Can you place the crocodile monitor tank outdoors?

Yes, a crocodile monitor tank is best kept outdoors because it is a huge lizard and may also pose a safety risk to other people at home.

Wil crocodile monitor love cold or warm weather?

This monitor lizard will love a moderate climate, which means not too cold and not too hot. Take this test; if you feel hot inside the room, then it’s also hot for your pets. If you are cold inside the room, then the area is also too cold for your pet.

How do you distinguish a female and a male crocodile monitor?

There are no distinguishing characteristics in female and male crocodile monitors.

Do crocodile monitor lay eggs?

Yes, these are egg-laying lizards that need a safe area where it can lay its eggs. It takes a few weeks to hatch the clutch of eggs, and hatchlings usually come out of the eggs ready and hungry.

Will crocodile monitor poison you?

The bite of a crocodile monitor can lead to a vicious wound and an infection. It is non-venomous, but the bite is dangerous because of bacteria in the lizard’s saliva and mouth.

What happens when you are bitten by a crocodile monitor?

A crocodile monitor has a nasty bite. The wound will become infected because of the bacteria in the saliva and mouth of the monitor. The best chance to survive is to clean the wound soon and use a disinfectant.

Will a crocodile monitor follow you around?

Yes, it will follow its handler and will also follow its victim. Once it has bitten a victim, it will follow it around and will consider it his prey. This lizard can also predict the behavior of its prey and will wait for it head-on.

Are locals afraid of the crocodile monitor?

Locals are very afraid of the crocodile monitor in such a way that they fear its bite and the possibility that crocodiles are near.

What is the warning pose of a crocodile monitor all about?

The warning pose is about a crocodile monitor standing with its tail at the back. It is still unknown as to what this pose means, but experts say that it is a way for the monitor to check on its prey.

Crested Gecko Care Sheet

Cuban False Chameleon Care Sheet