A practitioner’s guide to bearded dragons

Bearded dragons, with their prehistoric appearance, engaging personalities, and ease of care will certainly be a popular reptile pet for years to come

"Corvus" Photo courtesy Alicia Crawford
“Corvus”
Photo courtesy Alicia Crawford

Depending on the reference source, the central bearded dragon (Pogona vitticeps), which is native to Australia, is either the most popular pet lizard, or at least in the top three. Regardless of where they rank in sales, because of their great personalities, hardy dispositions, and ease of care, most people agree they are one of the best reptile pets on the market. Because of their popularity, “beardies” are commonly presented to veterinarians for care and advice.

Husbandry

Beardies are diurnal, omnivorous, and social animals. They are simple to care for and seem to “enjoy” being around people, making them great for first-time reptile keepers.

The wild or native dragon is a patterned sandy brown with rough skin and covered with small spines along their sides and chin. Both the male and female have a protrusible “beard” that extends when displaying aggression (rarely seen in captives). When stressed or ill the beard will turn black.

These animals reproduce easily in captivity, and selective breeding has produced about a dozen different “morphs.” Simple changes in color are referred to as “fancys,” but animals further from the norm, specifically referring to obvious changes in the skin, spines, and claw types, are classified into one of several morphs. Examples of common morphs include the leatherback, silkback, hypomelanistic, translucent, zero, and German giant.

In the wild, a beardie’s lifespan is around 10 to 15 years, but there are reports of animals in captivity living past 20 years. Full grown, they rarely reach 2 ft long, tip to tail, allowing them to live comfortably in a 75-gal terrarium.

Sexes appear similar in appearance, but mature males have larger femoral pores under their thighs than similar-sized females.

Figure 1: When ill or stressed a dragon’s beard will usually turn black. Photos courtesy Douglas Mader
Figure 1: When ill or stressed a dragon’s beard will usually turn black.
Photos courtesy Douglas Mader

Common medical conditions

Figure 2: Animals housed on sand will often eat the substrate that can cause life-threatening impactions. If not caught early, surgery may be the only treatment option.
Figure 2: Animals housed on sand will often eat the substrate that can cause life-threatening impactions. If not caught early, surgery may be the only treatment option.

As with most reptiles, bearded dragon morbidity is often related to improper management and nutrition. If the above guidelines are followed, these animals tend to prove to be hardy pets. That said, there are some common presenting conditions practitioners should be familiar with.

Nutritional secondary hyper-parathyroidism (aka Nutritional Metabolic Bone Disease, or NMBD)

NMBD is one of the most common disease conditions affecting captive reptiles, especially lizards.

Insectivores and herbivores need the correct combination of dietary vitamins and minerals (Vitamin D, Ca++ and Phos), as well as UV-B exposure and appropriate ambient temperatures or they may succumb to this management-caused morbidity. Young, growing dragons, and adult egg-producing females are especially susceptible owing to their increased demand for dietary calcium.

Immature dragons suffer from typical signs of fibrous osteodystrophy, such as rubber jaw, spongy thickening of the long bones, deformed skeleton, and pathological fractures. Both juveniles and gravid females can also present with hypocalcemic tetany.

If caught early and husbandry deficiencies are corrected, this condition can be reversed. Advanced stages of disease can also be managed, but deformities to the skeletal system may never resolve. Females often need to be spayed to prevent future events. Proper husbandry and diet are paramount to prevention and maintenance.

Periodontal disease

Like dogs and cats, bearded dragons also suffer from dental disease. Beardies have acrodont teeth, meaning they are adhered to the ridge of the jawbone without sockets. When broken off they are not replaced. It is not uncommon for older dragons to present with only a bony ridge remaining as their surface for mastigation.

Periodontal disease, as in companion mammal pets, may present as a loss of appetite, gingivitis, oral bleeding, tooth loss, or dysphagia. It is not known why dragons seem to be overrepresented with this condition (as opposed to other lizards), but diet has been suspected, as this has not been reported in wild conspecifics.

Figure 3: Females (top) are differentiated from males (bottom) by their much smaller femoral pores.
Figure 3: Females (top) are differentiated from males (bottom) by their much smaller femoral pores.

Just as in dogs and cats, treatment consists of proper dental scaling, extracting diseased teeth as needed, antibiotics, and analgesics. Prognosis is good if caught in time, but those left untreated will eventually die, usually of sepsis and inanition.

Atadenovirus

Typically associated with neonates and juveniles, this viral disease causes typical “sick lizard” signs, such as anorexia, diarrhea, lethargy, wasting, failure to thrive or grow, and neurologic symptoms. Adults are also susceptible, but not seen as frequently as the younger animals. Subclinical carriers are suspected, but it is also believed to be passed vertically through the egg.

There is no treatment available and the prognosis is grave. The intestines, pancreas, kidneys, and liver are most commonly affected, with the latter showing evidence of severe necrosis on histopathological analysis.

Antemortem diagnosis can be made via PCR testing. Positive animals should be isolated and culled to prevent transmission to conspecifics.

Coccidiosis

Coccidia (Choleoeimeria pogonae, Isospora amphiboluri, Eimeria spp.) are commonly found in the feces of even normal, healthy beardies—this is referred to as coccidiasis. The mere presence of Coccidia spp. in a fecal sample of a healthy animal is not justification for treatment. Coccidia with concurrent morbidity is referred to as coccidiosis. Sub-adults seem to be more susceptible to coccidiosis as are animals subjected to immunosuppressive conditions (poor husbandry, co-morbidities).

Figure 4: A yellow CANV lesion (red arrow). If caught early and treated aggressively these can be cured.
Figure 4: A yellow CANV lesion (red arrow). If caught early and treated aggressively these can be cured.

Clinical signs are nonspecific, such as anorexia, wasting, failure to thrive, and, ultimately, death. Treatment is generally well tolerated and effective with Ponazuril, 30 mg/g, PO q 24h for three treatments, and repeated in two weeks.

Microsporidiosis

Microsporidia, originally thought to be a protozoan, has been reclassified as a primitive fungus. In beardies specifically, the microsporidian Encephalitozoon pogonae has been associated with several colony outbreaks, including animals housed communally in pet stores. This pathogen is frequently seen in association with either or both Atadenovirus or coccidiosis (I. amphiboluri).

Similar to other pathogens, bearded dragons affected with microsporidia show typical “sick lizard” symptoms. The organism can affect multiple tissues, generally resulting in widespread organ failure. Diagnosis can be made via PCR testing. A Gram stain of oral secretions or fresh feces may reveal the fungal organism. Prognosis is grave.

Mycotic dermatitis

Bearded dragons are seemingly exquisitely sensitive to fungal infections, specifically with a fungus known as the Chrysosporium anamorph of Nannizziopsis vriesii (CANV). The patients present with sometimes deep ulcerations and yellow discoloration of the skin (hence the common name—yellow skin disease). This is highly contagious to other dragons and can cross over to other reptile species. CANV is often fatal due to its destructive nature.

Figure 5: A severe cephalic aneurysm. A contrast CT was performed to identify the location of the leaking vessel. A vascular clip was surgically applied. The patient recovered uneventfully and lived for an additional five years.
Figure 5: A severe cephalic aneurysm. A contrast CT was performed to identify the location of the leaking vessel. A vascular clip was surgically applied. The patient recovered uneventfully and lived for an additional five years.

Treatment involves aggressive therapy with debridement of lesions, systemic voriconazole (10 mg/kg, PO q 24h), and topical antifungals. Treatment may be prolonged, and severe scarring can be expected in some cases.

Cephalic aneurysms

Although most commonly associated with the head, aneurysms have been reported in tissues throughout the body in beardies. In the head, lesions usually arise from the internal carotid or from a portion of the aorta when reported elsewhere. Patients present with large, fluid-filled masses on the side of the head, along the spine, or on an extremity.

The cause is not known. There have been no reported successful medical treatments, but there have been a few isolated cases where surgical intervention has prolonged the patient’s life. Depending on the location of the aneurysm, the prognosis is guarded to grave.

Conclusion

Bearded dragons, with their prehistoric appearance, engaging personalities, and ease of care will certainly be a popular reptile pet for years to come. Veterinarians choosing to treat exotic pets are encouraged to learn more about these fascinating animals.

10 CLIENT TIPS FOR CARE

Whether your client bringing in a bearded dragon is a first-time reptile owner or new to the species, the following can be helpful reminders to them to give their pet the best possible care at home.

Environment

1. Beardies do well being housed solo. When housed together, especially in small cages, dragons may fight and cause severe wounds to their conspecifics.

2. Young beardies should be housed on newspaper, paper towels, or reptile carpet. The latter looks and feels like grass, and is easily cleaned and disinfected. Young animals tend to eat substrate, especially if food gets mixed into it, and impactions can ensue. Adult dragons can be maintained on reptile carpet or plain dirt. Again, avoid sand as it can cause impactions if consumed.

3. Dragons do like to climb. Large rocks and stout branches should be available as cage enrichment. These items will also aid the beardie during times of ecdysis.

4. Beardies are acclimated to warm temperatures. Their housing should have a thermal gradient established where the cool side of the tank is around 85 F progressively increasing to a basking spot on the opposite side in the range of 95 to 110 F. “Hot spots” for basking can be created with either a basking light or ceramic heat emitter. Nighttime lows should not be less than 65 F.

5. If housed indoors, these diurnal lizards require full spectrum lighting (UV-B, wavelength 290-320 nm) for 12 to 14 hours a day, preferably paralleling natural daylight changes. The lights should be inside the cage and not directed through glass.

Food and water

6. Being omnivores, beardies do well on a diet of both animal and plant protein. Juvenile dragons should have a ready supply of baby gut-loaded or vitamin-dusted crickets. A small dish of finely chopped mixed vegetables, generously misted with water, should be available at all times. Any food left over at the end of the day should be discarded and replaced with fresh the following morning.

7. Sub-adult to adult beardies can be meal fed once daily to every other day as they age. Along with fresh vegetables, vitamin/mineral supplemented adult crickets, locusts, cockroaches, waxworms, mealworms, silkworms, butterworms, red worms, earthworms, and zophobas are all well accepted. Lightening bugs have been shown to be toxic to dragons and should be avoided.

8. Regarding the offered veggies, chopped leafy greens, such as romaine lettuce; yellow, spaghetti, or acorn squash; green beans; parsnip; sweet potato; snow peas; and finely diced carrots can all be used in rotation. Fruits are primarily sugar and water and should be avoided, especially in young growing dragons.

9. Water should be available at all times. Placing a large shallow bowl in the cage is a great way to offer a drinking source as well as a place for the beardie to soak. All veggies should be washed and misted prior to being offered.

10. Finally, misting the cage walls, or even gently, directly on the animal itself, will also provide necessary hydration.

Douglas R. Mader, MS, DVM, Diplomate ABVP (canine/feline), Diplomate, ABVP (reptile/amphibian), Diplomate, ECZM (herpetology), Fellow, Royal Society of Medicine, received his DVM from the University of California, Davis in 1986. In addition, he completed a residency in primate and zoo animal medicine. He is a consulting veterinarian for the Monroe County Sheriff’s Zoo, the Key West Aquarium, Dynasty Marine, the Sea Turtle Hospital, the Everglades Alligator Farm, and the Theater of the Sea. Dr. Mader is an internationally acclaimed lecturer and is on the review boards of several scientific journals. He has published numerous articles in scientific and veterinary journals, national magazines, and, is an author-editor and co-editor of three textbooks on reptile medicine and surgery.

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