Spade-Headed Wormlizards: Trogonophidae

These wormlizards move oddly when they are tunneling. Instead of forcing their heads forward into the soil, they turn their heads up on one side and then up on the other, scraping the sharp sides of the face in this back-and-forth swiveling motion, and scrape away dirt. Just as twisting an apple corer will cause the corer to cut into and through an apple, swiveling the head of one of these wormlizards slices into the soil to make a tunnel. This swiveling motion is known as oscillation (AH-sih-LAY-shun). Besides cutting through the soil, the oscillation packs the dirt against the sides of the tunnel to make it smooth and rather strong. Although the head turns back and forth, the rest of the wormlizard's body does not. Its body's upside down "U" shape helps the wormlizard grab hold of the soil with its belly side and keep its body still. In addition, its very short tail digs in to the bottom of the tunnel to hold the body in place while the head swivels.

Because they have tiny eyes, if they have them at all, these wormlizards do not rely on vision to find their prey. Instead, they have excellent senses of hearing and smell. Although their ears are hidden by scales, they can hear even small movements, like a termite taking a few steps somewhere else in the soil. They also stick out their forked tongues to pick up chemical odors, then draw the tongue back inside the mouth to touch a special organ on the roof of the mouth. This organ, called the Jacobson's organ, smells the chemical odor.

Their underground homes provide considerable protection against predators (PREH-duh-ters), or animals that hunt other animals for food. Sometimes, when they are on the surface, however, they may face a predator. Unlike wormlizards in other families, the spade-headed wormlizard cannot drop the tail, a tactic that other species use to escape attackers. Instead, wormlizards roll over to be belly-up, and they stop moving. Predators may be surprised by the color or the belly or may lose interest because the wormlizard is so still. Either way, this behavior apparently helps the wormlizard to live another day.

The females of some species of these wormlizards give birth to about five baby wormlizards at a time. Scientists believe that some other species lay eggs. Little else is known about the courtship, mating, or reproduction of these animals.