Mistakes in husbandry and feeding lead to preventable diseases in Australian lizards. On the other hand, education and medical care help.
Along with European tortoises, bearded dragons are among the most common reptile species kept as pets and are therefore often presented as patients. This article aims to familiarize you with the animal species as well as with the diagnostics and therapy of these Australian lizards.
Of the eight bearded dragon species currently described, only the striped-headed bearded dragon (Pogona vitticeps) and – much more rarely – the dwarf bearded dragon are commercially relevant in Europe. Both species are found in central Australia, a region characterized by hot, dry summers with temperatures between 30 and 40 °C and a cooler and rainy winter period with temperatures between 10 and 20 °C.
The animals are facultatively omnivorous and can be seen as descendants of cultures. The natural habitat is characterized by hard-leaved and woody vegetation, which is what the animals’ digestive tract is designed for. The endodontic saw blade-like teeth are used to bite off and a pronounced large intestine serves as a fermentation chamber for the fermentation of the cellulose-rich food. A study by Oonincx et al. (2015), in which the gastric contents of wild animals were removed using gastric lavage and then analyzed. This occurred in parallel with termite mating season, so numerous winged termites could be detected in the stomach contents. Nevertheless, the vegetable content in the stomach content was over 40 percent. If one considers the short flight phase of the termites and if one takes a critical look at the efficiency of a gastric lavage sample, it can be assumed that the proportion of plants in the diet is considerably higher. This is consistent with the evidence of some diet-related diseases in bearded dragons fed on one side.
Male bearded dragons are solitary and territorial. The dominant male likes to take an exposed sunbathing spot, which is intimidating to other animals. If a territory boundary is violated, the territory owner initially threatens with a cautious nod of the head. Then the throat area (beard) puffs up, turns dark and nodding is intensified. Only when this is ignored does a fight ensue.
Breeders and retailers recommend keeping one male with two or more females and feeding them with plenty of insects. From a veterinary point of view, both must be viewed extremely critically. Ideally, the animals should be kept individually and only allowed together during the mating season. Mating and egg-laying behavior can certainly be seen as an enrichment of behavior and, against the background of induced ovulation, also as a prophylactic measure for the so-called pre-ovulatory laying difficulty. However, the hatching of the eggs must be questioned critically, since the market is oversaturated with male animals in particular.
While dwarf bearded dragons are reasonably easy to keep at 120 × 60 × 60 cm, striped bearded dragons require terrariums that are at least twice as large.
If several animals – under no circumstances several males – are kept together, the terrarium should have a square floor plan with an area of at least 2 × 2 m. With rich structuring and the offer of several sun spots, the animals can avoid each other. Especially in narrow terrariums, the dominant male sits at a central, elevated point and subtly stresses the other animals. It often does this by laying on top of other animals, which is often interpreted as “cuddling” by inexperienced owners but is not part of the behavioral repertoire of a non-social species.
When kept individually, the terrarium should never be less than 0.5 m2 in area. The usable area can be increased using climbing opportunities and various plateaus. Different temperature, light, and humidity zones should be created in the terrarium. As a rule, this is achieved by an acentric, intense sun lamp and a hiding place at the other end of the terrarium. This creates a bright, warm (approx. 40 °C) and dry place in the sun. In the hiding place, the temperature should then be below 30 °C, which increases the humidity there. Avoid wet or even swampy areas.
Since bearded dragons cover their vitamin D3 requirements through their synthesis, a corresponding supply of UV-B radiation is necessary. Combined mercury evaporators have proven their worth here.
When installing these lamps, care must be taken that there is no pane of glass between the light source and the animal to filter the UV radiation, although the minimum distance must be strictly observed. The lamps are often hung lower to achieve higher temperatures in the basking area, which may lead to skin tumors.
The substrate should be suitable for burrowing but is also ingested orally by the animals. Instead of sand or clay-sand mixtures, more easily digestible materials such as earth or coconut fibers are suitable to avoid constipation.
Even bearded dragons, as classic desert animals, are rarely observed drinking and if the additional water requirement is low with appropriate green feeding, fresh water should be permanently available to the animals. When it comes to nutrition, fiber-rich green fodder (meadow herbs, lettuce, no fruit!) is the top priority. The previously washed feed should not be cut into small pieces but offered whole to keep the animals occupied. Biting reduces tartar build-up and is made easier if the feed is secured by tying it to a branch. While young animals can still cope with a higher proportion of insect feeding and also need them during growth, the animals should almost exclusively be fed vegetarian from the age of one year. With a balanced diet and good UV lighting, there is no need for additional substitution of vitamins and minerals. Cuttlebone shells can be offered in the terrarium to supply calcium to laying females. If vitamin preparations are used, an oversupply of vitamin D3 must be avoided to prevent organ calcification.
Most bearded dragons find their rhythm for hibernation and are hardly influenced by the temperature and light programs of the owners. Animals are often presented that already withdraw in August or still want to sleep in March despite high temperatures.
Since there is no difference between sick animals from the outside, it is advisable to check the blood chemistry. During hibernation, the animals should be kept in a quiet place at 16 to 18 °C without artificial lighting. Drinking water and a fodder plant (e.g. Golliwog) should be available in case the animals interrupt the resting phase.
Handling of bearded dragons
Bearded dragons are peaceful. However, their sharp claws can cause scratches if the animal tries to escape over the hand. Bearded dragons do not actively snap at humans. However, you should be careful not to get your fingers between your jaws, especially with oral inputs. The animals have a strong jaw closure and perfectly fitting, pointed teeth, which are used to sever the tough vegetation of the desert.
For clinical examination, the bearded dragon rests on the flat left hand of right-handed people. With the right hand, the tail is first positioned dorsally at a 90° angle to be able to assess the base of the tail. In this position, the males’ two hemipenes are prominent, even in newly hatched juveniles. The cloacal region is examined for contamination. Then the right hand palpates the coelomic cavity (not too hesitantly) from cranial to caudal. With a little experience, increases in circumference, gas build-up, and cong, the question can be easily palpated. The oral cavity is then examined.
The diseases of bearded dragons are diverse and cover the entire spectrum of veterinary medicine. Nevertheless, some disease complexes occur more frequently.
Inadequate feeding promotes the formation of tartar. This can lead to significant infections of the jaw. Accordingly, the animals should be examined regularly and, if necessary, treated under anesthesia at an early stage.
Accumulation of mucus in the oral cavity leads to massive respiratory symptoms and is often interpreted as pneumonia. However, the mucus can also be the result of stress-induced gastritis, which is not uncommon and cannot be treated with antibiotics. On the other hand, germs that are difficult to detect hematogenous can get into the lungs and cause high-grade pneumonia that is difficult to treat. Ideally, germ cultivation with an antibiogram would therefore have to be carried out with material from the lungs (transthoracic pulmoscopy for sample collection), which is expensive in practice. Tracheal swabs are at least a step in the right direction.
Regular fecal examinations are among the sensible prophylactic measures. Oxyurids are very common in reptiles in general. Since they have a direct development cycle and are quite hazardous to health if infested, they should always be treated. Unfortunately, there is no correlation between infestation density and egg excretion. Elimination in the terrarium is difficult if not impossible.
The treatment of coccidia is similarly difficult. These can also be dangerous for adult animals, as they can damage the intestinal wall and cause hematogenous infections in other organs (liver, lungs, heart, etc.). Flagellates of the trichomonad type are also found very frequently They should be treated for inefficient digestion. Bile duct coccidia is rarely detected. Both therapy and success control are difficult.
It is not uncommon for animals to try to compensate for a lack of minerals by taking in sand and other substrates. Depending on the substance and extent, serious constipation is the result. Therapy approaches with infusions (Ringer’s solution, 10–20 ml/kg), fiber-rich feeding, vibration, ns, and enemas are not always effective. Sometimes s surgical repair is unavoidable. The use of paraffin oil should be obsolete by now.
When bearded dragons are kept in mixed-sex groups, the sexual pressure on the females is usually very high. Symptoms of deficiency appear no later than the third clutch in a row and the calcium reserves are no longer sufficient to trigger the laying process. A special form is the preovulatory laying difficulty. This is where ovarian follicular stasis occurs. While the classic laying problem can still be resolved with calcium supplements (10–100 mg/kg) and oxytocin (4 IU/kg), rapid surgical intervention is required for follicular stasis. Since all cases were preceded by a longer phase of vitellogenesis (yolk formation), there are considerable deposits of fat in the liver. These can massively impair the metabolism of anesthetics.
Diet-related calcium-protein deposits in the gallbladder are common in bearded dragons. These are initially rubbery and then harden through calcification. A tentative diagnosis can be made by palpating the blocked gallbladder and confirmed by ultrasound. The gallbladder needs to be surgically opened as soon as possible to empty it.
Feeding them with very protein-rich food (feeding insects), which is popular with keepers and traders, sooner or later leads to lasting damage to the kidneys. All known forms of gout occur. The uric acid levels should therefore be checked regularly, particularly in older animals. Early nutritional advice has the highest prophylactic value.
Since bearded dragons are rather incompatible, bite injuries often occur, especially when rearing young animals together. The toes and the tip of the tail are particularly affected. While the toes are usually amputated by the bite, dry ascending tail tip necrosis is common on the tail. This necrosis rises to the point of damage to the blood supply to the tail, which is usually undetectable. As long as the necrosis is dry, amputation should be avoided, since the necrosis will continue to rise even after surgical amputation in the supposedly vital tissue.
In adult animals, bite injuries occur particularly frequently in the form of a mating bite on the neck. This usually heals without complications, unless there are further bites in the injured area. It is therefore important to only keep males and females together at times.
Injections, blood draw
The importance of the kidney-portal vein system in reptiles has not yet been fully explored. Nevertheless, the motto is to carry out subcutaneous and intramuscular applications only in the front third of the body. Intramuscular applications are carried out in the dorsal muscles of the upper arms parallel to the humerus. The soft skin area in the armpit area is suitable for the subcutaneous application. The blood is taken and administered intravenously from the ventral tail vein. In male animals, the blood should not be taken too close to the cloaca to avoid damaging the copulatory organs and their holding apparatus.
The principles of balanced anesthesia also apply to reptiles. Accordingly, there are different anesthetic regimes for bearded dragons depending on the indication, previous illness, and condition. The ambient temperature also plays a decisive role: only at the preferred temperature, the so-called POTZ (preferred optimum temperature zone), which for bearded dragons is between 30 °C and a maximum of 40 °C. lies, the metabolism is fully efficient and the indicated dosages show their effect. One possible regimen starts with a mixed injection of ketamine (10 mg/kg) and medetomidine (100 µg/kg) SC. After about 20 minutes, the animal should be able to be intubated and the anesthesia can be maintained with isoflurane (oxygen as the carrier gas).
Bearded dragons are just as complex in their medical needs as any other animal. Accordingly, this article can only provide a rough outline of veterinary care.
Frequently Asked Question
Are bearded dragons suitable for beginners?
Which bearded dragons are suitable for beginners? Beginners should opt for the dwarf bearded dragon (Pogona henry lawson) and the striped bearded dragon (Pogona vitticeps).
How many bearded dragons should you keep?
How should you keep bearded dragons? Bearded dragons are loners. Keeping them alone in the terrarium is therefore species-appropriate. If you want a group of bearded dragons, you should only keep one male in the terrarium.
What animals can you keep with bearded dragons?
In principle, bearded dragons can be socialized with other lizards. However, we advise against this. The terrarium would have to be very large and the danger that the animals would have to suffer is too high. Therefore, one should refrain from such experiments.
How warm does a bearded dragon need?
If there are problems with molting, the housing conditions, especially the humidity and the vitamin/mineral content, should be checked. Climate design requirements: The soil temperature should be between 26 and 28°C with local warming up to 45°C. At night the temperature drops to 20 to 23°C.
How long does a bearded dragon need to sleep?
However, the researchers also discovered some differences: the lizards’ sleep cycle, for example, is extremely regular and fast: at a temperature of 27 degrees Celsius, a sleep cycle lasts only around 80 seconds. In contrast, it lasts around 30 minutes in cats and around 60 to 90 minutes in humans.
What fruit can bearded dragons eat?
Recommended fruit for bearded dragons are apples, mangoes, and strawberries. Cucumbers, tomatoes, peppers, and blueberries. You should stay away from citrus fruits and other fruits with a high acid content.
Can you take bearded dragons in your hand?
The animals only tolerate being touched because they usually have a very calm nature. In principle, however, bearded dragons belong in their living environment, which is the terrarium in this case. They should only be taken out for vet visits or to put in an outdoor enclosure.
Can a bearded dragon bite?
Bearded dragons can bite because they have teeth. The chances of a bearded dragon biting you are very slim because they are generally calm reptiles and are used to dealing with humans from birth.
How much does a bearded dragon cost to maintain?
Even the costs for the water bowl, the substrate, or the thermometer can quickly add up to a tidy sum. For starters, you should plan around 400 euros.