I’ve recently observed several frogs and toads to develop difficulties in feeding (American Bullfrogs, Gray Treefrogs, Southern Leopard and Green Frogs; several readers have written to me concerning difficulties with American Toads). It starts with what looks like “bad aim” and progresses to the point where the frogs cannot catch insects at all and must be force-fed. I’ve looked into the problem and found that a Vitamin A deficiency, leading to Short Tongue Syndrome, may be involved (please see this article by Dr. Kevin Wright of the Arizona Exotic Animal Hospital for details). I’d like to request that readers send me their own observations, so that we can learn more about this serious amphibian health problem.
Short Tongue Syndrome
The condition was first observed in captive Wyoming Toads, Bufo baxteri, an endangered species (please see photo).
According to the article mentioned above, studies of the feeding difficulties, labeled Short Tongue Syndrome, revealed that diets deficient in Vitamin A may prevent mucus glands associated with the tongue from producing enough saliva. The tongue is not, as the disorder’s name implies, shortened, but rather insects simply do not stick to the tongue when grabbed.
Other symptoms, such as swellings in the lower eyelid, have been reported in Leopard and various Poison Frogs.
Powdered supplements containing low levels of Vitamin A, or products that have expired or been improperly stored, may be implicated. Dr. Wright’s article (please see below) suggests possible treatments.
Vitamin A and Calcium: My Experience
The afflicted frogs and toads under my care were fed largely upon wild-caught insects during the warmer months, a strategy that has served me well for decades, so I suspect the problem does lie with the Vitamin A content of supplements used during the winter.
Several individuals have also exhibited poor coordination and difficulties in getting about, which sometimes points to Calcium-related disorders. I’m looking into several possibilities and will post updates.
Frogs: Vitamin A Deficiency; Dr. Wright’s thoughts, and research from the San Diego Zoo.