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1st Nov 2009

Animal Tracks in Practical Reptile - Frilled Dragons Article

Darren Bridgwood goes back to the age of the dinosaurs.

These stunning lizards have become closely linked with the film Jurassic Park, and interest in them has grown over the years since the film was released. I've always been fascinated by these creatures they're my favourite species. Everything about them is captivating, especially their amazing displays, enthuses Darren Bridgwood.

Frilled dragons (Chlamydosaurus kingii) have a wide range, extending from New Guinea south into Australia. Their colouration differs between localities, with those from Australia tending to vary from dark brown to deep red. Individuals from New Guinea, which is the source of captive-farmed individuals, are generally greyer overall, with a darker marbling effect. Growing to about 76 cm (30 in) in terms of their overall length, and having a frill which can be as large as 30 cm (12 in) in diameter when fully extended, these lizards have one of the most remarkable defensive responses in the reptile kingdom.

If a predator approaches, a frilled dragon will quickly shoot open its frill, using special long spines of cartilage, gape open its mouth and lunge menacingly towards the predator. If this fails to deter the attack, the frilled dragon will then retreat quickly using its powerful hind legs, to scamper into a nearby bush or up a tree. Once the dragon is on a tree, it is surprisingly difficult to spot as its colouration and markings help it to blend in remarkably well against the bark.


These lizards are primarily insectivorous, and mine receive a staple diet consisting mainly of crickets, mealworms and locusts. Waxworms are only offered in limited amounts, because although loved by most lizards, they contain high amounts of fat and therefore should only be fed as a treat I recommend a maximum of six per week. Pinkies should be offered twice weekly for adults and once per week for juveniles. Frilled dragons in the wild will eat basically whatever they can find, and they will also consume greens and fruits. Although not all will accept such foods, it is definitely worth trying to persuade them to do so, as these provide essential vitamins and minerals:

  • Vegetables
    • Romaine lettuce
    • Kale
    • Collard greens
    • Cucumber
    • Zucchini
    • Peas
    • Broccoli leaves and stems
    • Dandelion greens
    • Cabbage (small amounts, as can cause gas)
  • Fruits
    • Strawberries
    • Apricots
    • Mango
    • Melon
    • Blackberries
    • Raspberries
    • Peaches
    • Apples
    • Pears
  • Fruits and Vegetables to avoid
    • Tomatoes
    • Broccoli florets
    • Sprouts
    • Carrots (in high quantities)
    • Citrus fruits. These contain high amounts of citric acid and may damage the stomach lining, even causing ulcers.

Remember! Too much of any one thing is bad, so a good mix is always better! Iceberg lettuce contains mostly water which can cause diarrhoea, has no nutritional value.


Although captive-farmed dragons have a reputation for being lively and not easily handled, I have found that home-bred youngsters obtained at about a month old can become very tame. Start by encouraging the lizard simply to walk on to your hand, just above floor-level, so that if it rushes off, no harm will result. Never grasp one of these lizards this will cause it to try to escape. The more time that you spend with your lizard, the tamer it will become. My largest male has not been handled very much since the day I acquired him, but he has remained friendly and will sit quite happily and watch television just like a bearded dragon. Females can be slightly more skittish, but they can still be quite easily tamed and will readily eat food out of your hand.


Keeping frilled dragons requires plenty of space though, as they need a large area in which to climb and run around, protecting their frills from damage. The minimum dimensions for a vivarium for an adult pair should be around 1.8 x 1.2 x 1.2 m (6 x 4 x 4 ft). I have found they prefer several "hot spots" rather than a single basking area, in the range of 38-49 degrees Celsius (100-120 degrees Fahrenheit). The heating is positioned high up, and a large horizontal log is sited as a basking site, with the lower areas of the vivarium being cooler. I use 10 per cent ultraviolet tubes, with a reflector behind, which are left on for about 10 hours per day. These are located within 25 cm (10 in) of the dragons.

The enclosure is decorated with plenty of strong branches, held firmly in place as these lizards will jump from one to another. I also use a mix of plastic and live plants, which I spray regularly to maintain the relative humidity in the enclosure around 60 per cent. The plants help to make the lizards feel more secure, especially at first, and enhance the look of the vivarium. As a substrate, I use a 2:1 mix of peat and sand, which absorbs any excess moisture and does not turn mouldy or form clumps.


Frilled dragons are reasonably long-lived lizards, with a typical lifespan of between 12-15 years and have been recorded as living for as long as 20 years. Over time, the frills of males can become a bit torn but this is nothing to worry about and is relatively common. When purchasing a young frilled dragon, make sure that it is captive-bred, because even captive-farmed specimens can be afflicted by potentially-harmful microbes such as protozoa and flagellates, as well as worms and may need specialist treatment.

These lizards can also be susceptible to mites that will multiply rapidly in vivarium surroundings, and often localise behind the folds of lizard's skin which form the frill. They can be eliminated using a special mite spray that is safe for reptiles, and new arrivals should be treated accordingly as a precautionary measure. Faced with an outbreak of mites, you will need to spray the vivarium as well, to kill off these pests.

Can I Use Invertebrates from My Garden?

The main problem with invertebrates from these surroundings is that they may be carrying parasites which could infect the lizards, or may be affected by insecticides. I do not think it is worth the risk. If you want to offer more variety, order something a bit different such as silkworms, butter worms, roaches or mario worms and then you can be sure that your lizards are safe.

Should I Gut Load the Crickets?

I always gut load feeder insects before giving them to my frilled dragons. I personally use cricket food and a variety of fruit and vegetables, housing live food in a separate enclosure until it is needed. Not only does this help towards making the lizards' food balanced in due course, but it will also keep the live food alive for longer, saving you money. Live foods should be dusted with a multivitamin and mineral powder. I personally use both Nutrobal and pure calcium, mixed together in a ratio of 2:1 in favour of Nutrobal. This ensures the lizards have adequate calcium, helping to protect them from the risk of metabolic bone disease (MBD).


Determining the sex of these dragons can be quite difficult, but there are subtle clues that can be seen in youngsters from just a month old, in my experience. The snouts of males will start to become more elongated whereas those of females remain rounded, and the frills of males also begin to become longer and more visible from this age onwards. There are some behavioural differences, too. Females tend to prefer the higher areas of the vivarium, whereas the males tend to wander further in search of food, being more active, and nearly always feed first.

As they become adult, the differences between the sexes become more marked. Males have much longer heads and frills, while the hemipenal sacs develop as two prominent swellings down from the base of the tail. Male frilled dragons also have larger teeth and femoral pores running along the inside of the thighs which become enlarged during the mating season.

These lizards can be successfully kept in groups consisting of a male and several females, but males must be kept apart, as they will fight savagely. Initially though, the first signs of an encounter are very similar to that of mating. One of the males starts to wag his tail, and then begins head bobbing and arm waving at the same time. It is sometimes suggested that arm waving indicates submission, but I have noticed that it can mean quite the opposite if seen with other actions such as head bobbing.

The dominant male then begins to take small jumps forward as he keeps bobbing and waving to intimidate his rival. If this works, the other male signals his submission by tilting his head back until it is totally upright, repeating this ritual several times. One the other hand, if the other male refuses to back down, fighting will be inevitable.


Males are mature by about 12 months, and females can breed for the first time from 18 months onwards. Once you are ready to begin breeding, start the frilled dragons by removing the female from the male's company for about a month, and be sure to feed them very well during this period, providing the female additional calcium, for the eggshells. You can then reintroduce the female into the vivarium. Within about 10 minutes, you should start to notice the lizards interacting. The male will begin by wagging his tale, and then will proceed to engage in head bobbing and arm waving at the same time. If the female is receptive, she will often lower her head and make very subtle movements towards him. Within a further 20 minutes, she is likely to head down to the floor of the vivarium, and will dip her head for the male, with mating then taking place.

Egg Disposition

Females will generally lay their eggs in a single nest between two weeks and a month after a successful mating. Provide a choice of nesting sites, in the form of large plastic tubs measuring approximately 51 x 25 x 25 cm (20 x 10 x 10 in). These need to be filled with two parts of peat to one part of sand, which should be dampened slightly do it does not collapse, and yet is not saturated with water either. Once female frilled dragons have started laying, they will generally return to the same site in the future.

Removal of the Eggs and Incubation

When the female has laid her clutch, typically numbering between 7-23 eggs in total, these must be excavated very carefully. They should not be turned or rotated as they are transferred to the incubator, which should have been set up previously. I draw a small line on the egg for this purpose. The eggs then need to be buried halfway into the hatching medium, with the line correctly aligned. The incubator temperature should be between 28-30 degrees Celsius (82-86 degrees Fahrenheit), with the relative humidity set at 80 per cent.

Frilled dragons display temperature dependent sex-determination (or TSD), which means that the sex of the hatchlings is determined by the incubation temperature of the eggs. The cooler the temperature, so the greater chance of males being produced, whereas females predominate at the higher end of this range. The boundaries appear quite narrow, with 29 degrees Celsius (84 degrees Fahrenheit) giving a mix of sexes, but do not allow the temperature to rise above 30 degrees Celsius (86 Fahrenheit) as this may kill the developing embryos.

Rearing Young

When the young begin to hatch, it is generally best to leave them for up to 24 hours. Allow them to rest before moving them into the rearing tank, which should already have been set up for at least two weeks to check everything is working properly. Leave them here for a further day to absorb any of their remaining yolk sac, and then you can offer them a very limited number of crickets. I recommend size 2 browns, lightly coated in the supplements discussed earlier, allowing three crickets for each hatchling and watch to see how they react.

At first, they usually observe the bugs carefully, and then pounce. After the first one has been eaten, the rest are usually consumed very quickly. I then throw approximately four more each in the vivarium and repeat this twice a day. As they grow, the hatchlings are reared on black and brown crickets plus small locusts, with a dish of mini mealworms available to them as well.

The young are less adaptable than adults at this early stage. Although they require the same UV lighting, the heating in their quarters needs to be set up differently. In a small vivarium, I generally have one restricted basking area controlled by a thermostat to between 32-35 degrees Celsius (90-95 degrees Fahrenheit), because in such surroundings, if it was set to 46 degrees Celsius (115 degrees Fahrenheit) then the cooler end of tank would still be too hot, and the young are vulnerable to heat stress. In addition to a shallow dish of drinking water, I also recommend daily misting, to encourage them to drink, as well as maintaining the relative humidity in their vivarium.

* Darren has kept and bred reptiles for most of his life, and currently works as the reptile specialist at Animal Tracks in Ashington, Northumberland (tel 01670 851160/www.animaltracksonline.com), which offers a wide variety of reptiles, amphibians and invertebrates, along with all the necessary equipment and a host of other types of pets as well.

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Frilled Dragons