Biology and medicine of bearded dragons (Proceedings)

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Biology and medicine of bearded dragons (Proceedings)

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Aug 01, 2008

Bearded dragons (Pogona spp.) are omnivorous lizards that are native to Australia. Seven different species of bearded dragon are found in Australia, including the inland dragon (Pogona vitticeps), Northwest dragon (Pogona minor mitchelli.), Nullarbor dragon (Pogona nullarbor), western dragon (Pogona minor minor), Eastern dragon (Pogona barbata), Kimberley dragon (Pogona microlepidota), and Black-soil plains dragon (Pogona henrylawsoni). The inland bearded dragon is the species that is common to the pet reptile trade. This species is highly prolific in captivity, with (estimates of) over 250,000 animals being produced in captivity per year. As the popularity of these reptiles continues to rise, veterinarians can expect to encounter them more frequently in their practices. The purpose of this presentation is to provide attendees an overview of bearded dragon biology and common disease presentations.

Biology

Bearded dragons have a typical agamid-style, dorsoventrally compressed body. These animals were named for their dark, heavily-scaled gular beard. Dragons display their "beard" during both offensive and defensive behaviors. Dragons are acrodonts, so they have only one set of teeth. These lizards are geophagic, and can often be found "tasting" soil or other objects in their environment. Bearded dragons have long, narrow digits. These digits are adapted to climbing on rock and plant substrates. The tail of these animals is not autonomous. Males can be differentiated from females by the presence of large hemipenal bulges and large femoral/pre-vent scales.

Because of the vastness of the continent on which they originate, dragons may be found in both temperate and tropical climates. The humidity in these environments can vary dramatically, and the dragons may be found in arid to semi-arid areas. Bearded dragons are extremely adaptable to different habitats, and may be found in woodland, scrubland, and grasslands.

These animals are diurnal, sun-loving species. Dragons are primarily terrestrial, although they can also be semi-arboreal in those habitats that have appropriate climbing structures or plants. These "sun-loving" species prefer to bask in the morning and late afternoon hours in temperatures that approach and exceed 100o F. Because dragons are ectotherms, it is important to provide them an appropriate environmental temperature range. In general, a diurnal range from 85-100o F is appropriate; while a nighttime drop to 70-80o F will suffice. Dragons not provided an appropriate environmental temperature range may have a decreased metabolic rate and immune response, resulting in limited growth and chronic infections.

In Australia, bearded dragons are reproductively active during October. A clutch can range from 11-25 eggs. Eggs typically hatch in 55 days following incubation at 28o C. In captivity, female dragons may lay 3-4 clutches of eggs per year. It is important to monitor these highly productive animals closely, as they can expend significant amounts of energy on reproduction and die prematurely.