Moloch Lizard / Thorny Devil Care Sheet

Moloch Lizard

Scientific Facts

Common NameThorny Dragon
Scientific NameMoloch Horridus
Type of AnimalReptile
Natural HabitatAustralia
Length15-20cm (5.9-8 in)
Life Span15-20 years
Average Weight70-95g (2.5-3.4 oz)

Physical Description

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Moloch Lizard or Thorny Devil is known for their unusual and intimidating array of spikes that covers the entire upper side of their body. Their large spines may cause fear especially to predators, but these are entirely boneless. Their parietal spines on the skull are the only bony part on their head. For them to be able to camouflage easily, they are equipped with thick shields and spiny cones that have brown patches so that they can be seen as a thorny bush from afar.

A unique feature that they possess is the spiny “false head” on the back of its neck that serves as another defense mechanism to predators. The ventral surface of their body is covered in a non-overlapping, conical scales that had a hard texture. This complicated ventral surface helps in retaining and absorbing water through body contact.

Their ability to change in color is brought about by the temperature. In the morning, they are in color brown or olive, and as the temperature rises in the afternoon, their color changes into yellow. They also possess pale colors during the warm weather and darker colors during the cold weather.


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You can mostly see these species in the arid to semi-desert conditions in inland Australia, Western Australia, the southern half of the Northern Territory, South Australia and western Queensland. They like thriving in the heat or in sandy surroundings, grasslands, and scrubs where they can easily blend into their environment. 

They are found across central parts of Australia where you can see most of them apart from their origin place which is at the Western Australia where the climate is their home territory but since they already migrated in the Central parts of Australia, you can mostly see them in dry desert. Since these lizards have one of the most excellent defense mechanisms, they are one of the lizards that rule among the majority when it comes to their populations.

Behavior and Temperament

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Thorny Devil has a versatile personality where it has a lot of interesting adaptation in the wild such as storing themselves, capturing their prey, and drinking water. They are very good at camouflaging because they use their ability to change colors, whether in grey, red, orange or yellow. In defending themselves from predators they will tuck their real head between their legs while exposing the false head and thorny body making them bigger giving their predators the impression that they are hard to swallow. When they see a prey, they’ll freeze or form their body into rock-like while getting near their prospects.

You will often see them stand still in bodies of water, but you will not see them drink, experts prove that the design of their bodies allow them to absorb water from all areas of their body. This is a way for them to fully adapt during hot weather so that the salt is excreted while retaining their water still. They are a slow-moving reptile that is diurnal, at night they burrow themselves to keep them warm.

The way how they adapt to different seasons is through bimodal seasonal activity where they tend to become inactive during winter months which is the coldest season and during the summer where it is the hottest season. They are active during late winter, autumn and early summer. They do not like extreme coldness and hotness, that is why if you would take them into captivity, make sure to always check the temperature.

Breeding and Production

Leg-waving and head-bobbing are just simple gestures a male Thorny Devil does to attract females to mate. As soon as they reach the age of three, they can already start mating for reproduction. The mating season carries on from late August to early ownersDecember. For the breeding to be successful, they should be very well fed with ants during the winter season.

Once the courtship and mating are completed, the females burrow about 30 centimeters below the ground. They are expected to lay at least 3-10 eggs in the chamber burrowed. If the eggs are exposed to the medium to high temperatures, the eggs will break to free the hatchlings after three to four months. Hatchlings are independent, as soon as they hatch, they can start eating ants.

Thorny Devil Life Cycle

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The females would secure the place where they burrow, they will dig much deeper holes than their normal ones and before leaving, they will ensure to cover up signs of a hole or burrow. After the eggs hatched, they dig their way up to the ground’s surface. They are already equipped with spines just like their parents at an early age. Both males and females have the same growth rate during their first year, but the females start growing at a greater pace than males. 

The growth rate also varies depending on the season, during the winter season there are little to no changes in growth. It would take 5-6 years for them to reach maturity. The mating process occurs yearly and is already considered as a consistent process.

Eating Behavior

Thorny Devil is known as myrmecophagies, their diet consists of entire ants, but you can also feed them small insects. They usually eat in the morning and late in the afternoon. When they see a trail of ants, they lick them all through the use of their sticky tongue. Experts calculate that they can eat up to a thousand ants in a single meal. 

Size and Weight

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The female Thorny Devil is generally larger than males. Females have an average snout-vent length of about 45.5 grams to 88.7g while the males have an average snout-vent length of about 31.2 grams to 78.7 grams. The length of their body contributes to their body’s weight. Their body’s weight changes, either gaining or losing throughout the year by 30% depending on their activity. Their size and weight differ from one lizard to another based on their location, habitat, and diet that is why there is a variety of Thorny Devil in different sizes.


Their lifespan ranges from 15-20 years. Studies show that they can live longer when taken in captivity because breeders can attend to their needs. If they aren’t infested with different kinds of diseases and illnesses, expect that there is a higher chance for them to live longer.

Impact on the Environment

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Because of the high populations of ants in Australia, the impact of Thorny Devil doesn’t have an impact on the ant populations. In fact, the Thorny Devil helps balance the ecosystem. The population of Thorny Devil is threatened because of its natural predators such as large birds and other mammals. 

They are also vulnerable to habitat loss and disturbances. Since they are ectotherms they love basking anywhere such as in warm roads increasing the high risk of being run over by vehicles, so if in case you live near their habitat and you see them on the roads, guide them to a place where it is impossible for them to get hit by a vehicle or get hunted by abusive humans. 

Common Disease and Illnesses

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Thorny Devils are considered a hardy pet that does not require high maintenance, but there are still factors to consider in making sure that it will grow healthy to reach its maximum lifespan. Like other reptiles, they are also prone to different kinds of illnesses especially if their habitat in captivity is not well maintained.  They are equipped with defense mechanisms that is why you can easily tell if something is wrong with their functioning. If you observe an unusual behavior or changes in the physical appearance or behavior of your pet, then it is best to seek help from professional help which specializes in taking care of lizards. 

Metabolic Bone Disease

Their diet which is ants is not enough to sustain the nutrients its body needs. In captivity, make sure that aside from ants they are also given different kinds of supplements, especially those that are high in calcium and Vitamin D3. Metabolic disease is also a result of giving them an incorrect diet.


They may not be prone to parasitic infections, but they suffer from constipation due to impaction because sometimes they tend to eat unnecessary things that can’t be digested such as sand and garbage. They do not defecate on a normal basis, and sometimes it would depend on the temperature. Low temperature makes it difficult for the reptile to digest their food, so they become constipated. Make sure that your pet’s habitat is equipped with the right temperature and make sure freshwater series daily liable to keep them hydrated.


Even though they thrive in warmer areas, they are also prone to burns in captivity if the lighting equipment is not properly situated. Make sure that the light sources are placed at a distance. Minor burns can be treated with the use of antiseptic ointment, before applying to make sure that the area is clean.


Even though Thorny Devils has the capabilities to provide cuts or scrapes, they are also prone to it that is why in setting up your housing, make sure that there are no accessories that are sharp that can cut their skin because different cuts and scrapes can lead to infection if not treated immediately. If in any case that they are mishandled, they may be prone to broken bones that is why if you notice that your pet executes different kinds of defense mechanisms before handling it, it is advisable to just leave it alone to avoid the harm that you can cause them and the harm that they can give you.

Respiratory Infection

They are not comfortable in temperatures that are too hot and too cold. If they are exposed in this environment for too long, expect that your pet will be prone to different respiratory infections, especially that too cold or too hot temperatures may lower down their immunity. If there is no water that they could absorb, it can also lead to some respiratory infections.

Preventing Illness

Thorny Devils are considered hardy lizards that can live long. In captivity, there is a higher chance to exceed their maximum lifespan, which is 20 years if the different kinds of diseases or illnesses are avoided. If these are not avoided at least giving proper aid will help to regain their good health. Make sure their environment mimics the natural habitat so that their bodies will have better immunity.

Make sure to provide them with basic needs such as food, water, and vitamins. It is also important to promote cleanliness, clean their housing at least once every 2 weeks and also observe them on a regular basis so that you can attend to bodily problems immediately. You can avoid different kinds of diseases if you have a fixed schedule per week when to personally examine each part of their body.

Captive Breeding

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They may look fierce, they are not aggressive, and that is why they always attract captive breeders. If you were to breed them in captivity, make sure that the environmental conditions are excellent, they are naturally grown outdoors in their natural habitat and taking them in captivity may change their internal lifestyle that may cause some other health, behavioral and overall well-being problems. The breeders or owners should be able to check upon the potential cost of having a Thorny Devil basing on their diet and housing.

How to Care Reptile as a Pet


This species should be placed in an environment where they can freely move. You can make use of aquarium that is big enough that is equipped with artificial sand dunes and thorny bushes to make them feel that they are in the natural environment. As much as possible, place their housing in a place where there is minimal noise so that they will just stay calm or they won’t feel any aggressiveness.

Lighting and Temperature

They thrive in a hot environment that is why it is a must to give them a housing environment that mimics their natural habitat which is dry and humid. You may need to set up lighting equipment since Thorny Devil loves basking. If you are located in a region that is cold, you may need to set up heating devices or warmer. They are not comfortable in a too hot or too cold environment so always check that their housing environment is at the optimum level.


In the wild, they eat almost every day, but in captivity, since their energy is not always used, you may feed them at least thrice a week. You need to have a source of ants so that you can feed them at the right volume during mealtime. There are also available supplements in pet shops to maintain the needed nutrients for them to survive.


Thorny Devil doesn’t need much caring, they do not like being handled. When they are threatened because of human touch, their spines may prick the human hands. Taming them is necessary for captive breeding. As much as possible, if not needed, avoid holding them too often so as not to irritate them or bring out their aggressiveness.


Thorny Devils have high levels of digging activities, especially when it is cold. Make sure to use dry sand or soil as substrates. To mimic the natural environment, make use of thorny shrubs or bushes where they can hide. The use of dry sand will help if you do not intend to use any heating device because it has the ability to conserve the warm temperature of the body. However, if you would use soil, it can easily make the body cold that is why you may need to ensure that your pet will still absorb heat. If you are planning to breed in captivity, you should add more substrate where they can burrow and lay their eggs.


For hygiene and sanitation, make sure to regularly clean their housing. Change their substrate every 2 weeks to avoid dirt-causing illnesses. The unsanitized environment is the starting cause of different health problems. It is also advisable to always clean your hands before handling them to avoid parasite transfer.


Hydrating is one of the activities of the Thorny Devil. They love basking in an underground water source or in any bodies of water to absorb water for the regulation of temperature into their bodies. Make sure to place a bowl of water in their housing to keep them hydrated. 

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Since these species are considered endangered in different regions apart from Australia, you may have a hard time acquiring it in your local pet shops. You can find pet owners on the internet that are actively breeding Thorny Devils. There are also pet shop websites that sell Thorny devil but its seasonal. Purchasing these reptiles outside your country will cost a lot because you may need to pay for the shipping and the documents needed plus the actual price of the item 

Danger to Humans

Thorny Devils are attractive, they may look aggressive because of their spikes, but they do not pose a danger to humans. They may not be an ideal pet for beginners, but they are the hardy ones. If you are considering getting one, make sure to be prepared in housing it in a large tank so that it can still move according to its active lifestyle.  They are not comfortable being handled by humans, just be cautious in doing so because their spike can prick human hands that is why wearing gloves is advisable.

When they pricked your hands or when they bite you the wounds may be infected if not treated properly. They may not possess venom that is fatal, but it can give you fear that is traumatizing so before getting one, make sure to do your research about how to deal with them to avoid problems in the future. 

Thorny Devil Interesting Facts

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  • This type of lizard has the ability to eat at least a thousand ants in a meal or at least 45 ants in a minute.
  • They are a good runner at a maximum speed of 60 kilometers per hour.
  • They are named after a sacrificed god, Moloch Horridus. Moloch means a horrible king smeared with the blood of human sacrifice and the Latin word horridus can mean rough, bristly, or dreadful.
  • Their spikes are almost the same as the thorn of a rose.
  • They exhibit jerky movements, they walk slowly, and sometimes they rock back and forth and freeze in place especially if they suspect that a predator sees them. 
  • They have distinctive fecal pellets, which are black prolate spheroids and glossy. They have the ability to distinguish their defecation site from the place where they eat and bask. Usually, they defecate away from their place.
  • They prefer to have a bimodal seasonal pattern where they choose to be active or not. They may thrive in hot temperatures, but they do not like extremely hot or cold temperatures.
  • Their spikes do not serve as a protective gear, but this gear allows them to collect water in an arid habitat.
  • Some cultures do not permit taking it into captivity because they see it as a representation of evil that may cause bad omen.

FAQ Section

How do they obtain water?

They acquire water from the rain directly or through the dew that condenses on their bodies overnight, during rainfalls, or by scrubbing up against dew-coated grass. They can also absorb water by just standing up in any bodies of water. Any water that gets through its thorns is drained by capillaries up to its mouth.

Why are they named Thorny Devil?

It was named Thorny Devil because of its appearance that has painful spikes and because of its intense lifestyle that gives the idea that they are aggressive. Aside from their looks, smaller prey would also perceive that they are the king because of their stance.

Why do they puff to appear bigger?

Puffing is one of the greatest defense tactics of Thorny Devil. They puff so that their predators will be intimidated by their appearance, and there is less chance for it to be swallowed for food. This is also a way for them to let their predators know that they are capable of something so instead of going near, their predators are already frightened.

Are they endangered?

They are not considered endangered in the Australian region but if experts would look at their total population in the world, they may be considered on the list that is why they are trying to create a new breeding ground in captivity so that they can be distributed in some parts of the world that can serve as their new habitat. Taking it into captivity requires some process because this may be a cause of the deterioration of their population in the future.

What is the use of their horns for them?

Their horns serve as another self-defense for them, they just try to intimidate potential predators. They can use their horns to attack or prick their predators. It doesn’t serve too much purpose but it adds up to its unique attributes. 

Can they be taken care of by beginner lizard owners?

Thorny Devil is a hardy type of reptile, but it needs a home that exactly mimics its natural environment. It may be costly to set up a tank or an aquarium designated for them plus their diet. You also need to ensure that they have enough substrate especially when they are about to hatch.

How does it move?

They move slowly and when they see a predator, they jerky gait and form like a rock to somehow camouflage and confuse their predator.

Are they a voracious eater?

When it sees a flock of ant, it captures its prey through the use of its sticky tongue at a rate of 45 ants per minute. In just a single meal, they can eat at least 600 to 3000 ants.

Can they change the color of their scale depending on their mood?

They can change colors depending on their activity and the temperature. When they race away from predators, their skin’s color will change into yellow with bright spots of brown and red. When the temperature is cold, their skin’s color will change into the green with dark spots.

Can they be tamed?

They are not quite comfortable being touched by humans, but if you’ve taken them in captivity at an early age they won’t be able to adapt their fierce and aggressive behavior allowing you to tame them easily. You can start by learning some tricks or techniques on how to feed them in that why you are using the classical conditioning way of letting them know that you are no threat to them.

How do they drink from their feet?

Aside from their belly parts, they can drink water from their feet just by standing in a basin with water or through other bodies of water with the tiny channels and micro-grooves located on their skin.

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