Emerald Monitor

Image Credit : Mickael Leger Photographie


Varanus prasinus is a small to medium-sized arboreal monitor lizard. It is known for its unusual coloration, which consists of shades from green to turquoise, topped with dark, transverse dorsal banding. This coloration helps camouflage it in its arboreal habitat.

It uses its prehensile tail and long claws to grip branches. Unlike other varanids, this monitor defends its tail rather than lashing with it for defense when threatened. The soles of the feet of the emerald tree monitor have enlarged scales which aid the lizard when climbing.

  • Scientific name : Varanus Prasinus
  • Distribution : Australia (Queensland), New Guinea
  • Average Size : 0.8 m (2.5 ft)
  • Life Span : 15 years or more
  • Difficulty : Advanced


A custom built enclosure 1.8 meters (6 feet) tall, 1.2 meters (4 feet) wide, 0.6 meters (2 feet) deep minimum. Most of the enclosure should be solid wood, glass or plastic to keep in humidity and heat. Install a couple air vents for ventilation. The walls inside should be covered in something the monitors can use to climb, cork sheeting or cork tiles work great. Build a central tree or attach a lot of branches everywhere so they can climb, walk and jump around as they are a very active species. Use some fake vines or plants around the branches, real plants will be destroyed and possibly chewed on. You will also need some cork tubes for them to crawl in and out of. The tubes provide security and a place for them to sometimes sleep.

Hide box

Use cork tubes and also a moss filled nest box. You can buy parrot boxes at the petstore or make them yourself for lone adults or babies. For breeding pairs you will need a much larger nest box because the females will also lay eggs in there.
A breeding nest box needs to be around 0.9 meters (3 feet) deep and filled to the top with damp moss, eco earth or a mix of both. I use a tall 13 gallon trashcan with an additional container attached to the top to make it taller. I also drilled a few holes on the bottom for drainage in case I add too much water to the moss mix inside.


Moisture retaining substrate is a must. Use moss, eco earth, dirt or very finely shredded cypress mulch mixed with any of those just mentioned. I personally use a moss and fine cypress mulch mix and add fallen leaves from outside in the fall season. Do not use sand, pebbles or rocks. Pebbles and rocks can be ingested causing impaction. This almost always results in the monitors death.

Lighting – Heating

I use a 5.0 UVB light and for heat, create a basking temperature of 44-48 °C (110-120 °F). The ambient temperature should be 27-32°C (80-90 °F). Lighting is on a twelve hour cycle. Night time temps should never go below 24 °C (75 °F).


Give them a large water bowl big enough for them to soak in. These monitors rarely drink from a water bowl though, and prefer to be hand misted. Gently spray their face with water every morning and they will drink it.


This should be above 70% but be careful to not overdo it. If you are always using a fogger and mister the cage will  become too wet and grow mold. The monitors can also develop a respiratory infection from too high humidity.
On the other hand, if humidity is too low, they will also develop a respiratory infection as well as become dehydrated and develop stuck shed. What works for me is misting the enclosure heavily in the morning by hand and then running a fogger for a few hours only. In the afternoon I let it dry out a little and in the evening I will hand mist again.


Feed daily a variety of foods so they have a balanced diet and don’t become bored eating the same thing everyday. I feed mainly insects like roaches and crickets. Less often I will feed moths, butterflies,silkworm,waxworm, hornworm and superworm.
I feed meaty items a couple times a month, these include rodents, birds, shrimp, ground turkey and cooked eggs.
Insects are gut loaded before feeding and dusted weekly with calcium plus vitamin D3 powder, I will also add this supplement to ground turkey. Once a month I will dust insects with a multivitamin.


Wild caught tree monitors are scared and hide a lot. It will take time for them to trust you and feel comfortable being held. If you work with them daily, just sticking your hand in the enclosure and sitting there, they will eventually get curious and come over. You can try putting your hand next to them and just staying still and work up to sliding your hand under them. It may take several months to get these wild caught monitors to trust you but it can be done.
Captive bred and born tree monitors are a different story. They are born without fear of people and become very friendly very quickly. Since CBB baby tree monitors are curious and bold, the only thing you have to do is stick your hand in the cage and they will readily climb out on it. As long as you never grab, constrict or scare your monitor, it will stay unafraid and grow into a friendly adult.


Wipe down windows and cage décor with plain water on a paper towel. Spot clean feces. Churn the substrate once a month so bacteria can decompose any fecal matter you miss.


If the humidity is correct (70% and above) you will not have any shed problems. There is no need to soak these monitors, they are not aquatic and do not like it. Soaking them will stress them out and cause them to be afraid of you. The only time you may need to soak them is if they have stuck shed on their toes or tail tips due to not being kept at proper humidity levels. It is important to get off stuck shed because it can restrict blood flow and cause the toes and tail tip to fall off.

Potential Health Problems

When you first get a tree monitor it is important to take it to a veterinarian for a fecal exam and health check. All wild caught tree monitors have parasites and need the appropriate medication to kill them. There are different medications for worms and protozoa infections, this is why you need a fecal exam to determine what medicine you need.
Many tree monitors also have respiratory infections from a combination of stress and being kept incorrectly by the supplier/pet store. These infections will need antibiotics your veterinarian can prescribe you. Sometimes tree monitors will have fungal infections. At first it may look like a gray area that’s going to shed or it may look like a bruise or burn. Eventually the area will spread or new areas will pop up. It does not heal normally and go away. You will need anti-fungal medicine for these areas. After treatment the area will heal and you will see a scar. After a few years, colored scales will grow over the scar and it will not be as noticeable. Fungus is very contagious and spreads through the air so quarantine in a separate room away from other reptiles as soon as you notice infection.
If correct care is given to a healthy tree monitor (free of infection/parasites) there should be no future health problems.



The Reptile Whisperer

The information contained in this care sheet reflect the opinions and methods of the mentioned breeder, based on their expertise and long-established experience.