Tongue problems are not uncommon in chameleons and are usually related to either traumatic injury and/or nutritional imbalances. Tongue trauma often causes a sudden onset of tongue paralysis. Types of trauma to the tongue might include getting the tongue wrapped around or caught on something in the enclosure, damage to the tongue by a live prey item, hand-feeding injuries (if the feeder accidentally grabs or pulls the tongue when it makes contact with the fingers), or even two chameleons shooting their tongues at the same prey item that get their tongues entangled. Occasionally, foreign bodies have been associated with tongue dysfunction, such as sharp insect parts that become lodged in the mouth or tongue tissue.

With nutritional deficiencies, there is typically a slower, more chronic loss of tongue function. The chameleon tongue's aim may become misguided, or the tongue's projectile length gradually decreases until the chameleon can project it just a little or not at all.

CASE REPORT
This juvenile male veiled chameleon presented for a sudden onset of inability to shoot its tongue at prey. On initial examination, the tongue was not visible in the floor of the mouth. Looking more closely, the tongue was actually swallowed and was directed backwards, down the esophagus and into the stomach!

The mouth was held open with strips of white adhesive tape (folded in half lengthwise) and the tongue was gently manipulated out of the mouth.

The chameleon returned for a recheck examination one week later. Upon opening of the mouth, the tongue again was difficult to find. In fact, the tongue was neither on the floor of the mouth nor swallowed! It was completely absent. It was suspected that the tongue was probably re-swallowed after the last examination, and over the course of the week was weakened, tore, and may even have been auto-digested by the chameleon's stomach. The only remnant of the tongue was the hyoid bone, seen protruding from the mouth in this image:

The hyoid bone is a piece of cartilage that serves as the rigid base of the tongue. The hyoid bone attaches to the hyolingual apparatus, a complex structure in the throat made up of cartilage and bone. In an analogy made by Ardi Abate (2001), think of the hyoid bone as an arm and the tongue as a long sleeve pushed up over the arm. The tongue is launched from the hyoid bone with the use of ringed muscles in the tongue.

TREATMENT and DIAGNOSIS
No treatment was indicated in this specific chameleon, except for instructions to hand-feed. Some chameleons that have permanently lost their tongues can actually learn to eat from bowls and will learn to go right up to prey items and grab them with their teeth rather than using the tongue.

When a chameleon presents with a tongue disorder, a thorough examination of the mouth should be made for trauma or foreign bodies, being careful to gently manipulate the tongue. Diet and lighting should be thoroughly reviewed and corrected if necessary. Tongue dysfunction may be responsive to injections of Vitamin E/selenium and/or calcium gluconate, and further work on this topic is warranted.