Weird jaws let tiny snake gulp fast.

An eating style and jaw structure unlike that of any other known vertebrate may give a minute predator an edge in its perilous hunts.

Texas threadsnakes raid ant nests to prey on the young, a bold move for such a small attacker. An adult threadsnake in the genus Leptotyphlops grows 6 to 8 inches long and a bit thicker than a strand of spaghetti, and it weighs about a gram. Its size renders the snake vulnerable to serious injury and death when attacked by ants.

This rather delicate predator turns out to have a unique jaw structure for high-speed gulping, thus minimizing time in a risky ant nest, say Nate J. Kley and Elizabeth L. Brainerd of the University of Massachusetts at Amherst. In the Nov. 25 NATURE, they describe videotaping the snakes in a Plexiglas feeding chamber.

Most snakes eat big prey by stepping their upper jaw, one side at a time, over the victim, essentially walking dinner into their mouths. The process takes minutes to hours.

Threadsnakes, however, depend on their toothy lower jaw, which is divided at the midline. The halves bend in, then out, "like a pair of swinging doors," as the researchers put it. The snakes can flip their jaws several times a second, pulling meals down the hatch in an eye blink. Kley notes admiringly, "They're able to pile away dozens of little ants in a minute."