Reptile & Amphibian Center

Metabolic Bone Disease (MBD) & Disorders in Reptiles

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Metabolic Bone Disease


Reptiles that eat primarily insects or plants are at risk for developing metabolic bone disease, which is caused by an imbalance in the levels of calcium, phosphorous, and vitamin D in their bodies. Snakes and other carnivorous reptiles that are fed whole prey generally get enough calcium and vitamin D in their diets, and metabolic bone disease is rarely a problem for them.


Symptoms and Types of MBD


Typical symptoms of metabolic bone disease include:

  • Limping
  • Bowed legs
  • Hard lumps along the legs, spinal column, or jaw
  • Softening and unusual flexibility of the lower jaw
  • Difficulty raising the body off the ground
  • Decreased appetite


If calcium levels in the blood become very low, depression, lethargy, twitches, tremors, hind end weakness, seizures, and death may result.


A turtle’s shell may become unusually soft, flared up around the edges, or pointed down at the rear. If the large “scales” of a tortoise’s shell (or scutes) have an abnormal pyramid-like shape, metabolic bone disease should be suspected.


Causes of Metabolic Bone Disease in Reptiles


Metabolic bone disease usually develops when dietary levels of calcium or vitamin D are too low, phosphorous levels are too high, and/or when inadequate exposure to ultraviolet-B wavelengths of light hinders normal vitamin D production and calcium metabolism within a reptile’s body.




A veterinarian will often diagnose metabolic bone disease based on an animal’s clinical signs, diet, and access to ultraviolet-B light; X-rays and/or blood work, including measurements of calcium levels, may also be necessary.


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