High-Power Ballistic Tongue Projection in Hydromantes

Salamanders of the genus Hydromantes in the family Plethodontidae have the longest tongues of any salamanders, by absolute as well as relative measure. This genus of salamanders can extend the tongue more than half the length of the body, excluding the tail. The species in this movie is Hydromantes platycephalus, which is from the Sierra Nevada mountains of California. It lives at high elevation in rocky areas along streams and at the edges of snow packs. It uses its webbed feet to climb vertical rock faces, and its long tongue to pick off its insect prey. Notice that it moves slightly backward from the recoil of the tongue being launched. The rate of this movie is 2250 images per second.

The projectile tongue of Hydromantes can be shot to 80% of body length, or more than 6 cm. Hydromantes is the only plethodontid genus found in the Old World, and is restricted there to Italy and a small part of southern France. There are currently seven recognized species in Europe. Hydromantes platycephalus is one of three species found in the New World.

The photo above shows H. supramontis capturing a housefly. Pass your mouse over the image to view the anatomy of the tongue projection system. Or view a complete diagram. Tongue projection distance in this photo is greater than in the video above, or about 6 cm.

This photo and figure show one of the amazing things we have discovered about Hydromantes tongue projection, namely that it is ballistic. The tongue skeleton is shot from the body of the salamander completely, and travels to the prey under its own momentum. The mechanism is like shooting a watermelon seed from between your fingers. We have also discovered that other plethodontids, like Bolitoglossa and Eurycea, also have ballistic tongue projection systems that they have evolved independently from a non-ballistic tongued ancestor in each case.