Sunbeam Snakes: Xenopeltidae

The two species of sunbeam snakes—the common sunbeam snake and the Hainan sunbeam snake—are among the world's most beautiful snakes. Their metallic-looking bodies shine different colors depending on how light bounces off them. When a sunbeam snake is in the shade, its back looks dark purplish brown or black, but when it slithers out into the sun, the large scales on its back and head erupt into a wave of color. Like a raindrop can bend sunlight to create a rainbow, this snake has scales that reflect sunlight into many colors. This property is called iridescence (IH-rih-DEH-sense). In fact, another common name for this snake is the iridescent earth snake. Young snakes, which are also iridescent, often have a white patch, or collar, on the upper neck.

Adults have slightly flattened bodies that are white, light gray, or light yellow on the bottom. The light color also extends up onto the lip scales. Sunbeam snakes have very small eyes on a head that is about the same diameter as the neck, so the head is not as obvious as it is in vipers, pythons, and many other snakes. The head flattens out toward the snout, giving it a wedge shape suited for digging. The skeleton also has some interesting features. The bone in the front of the upper jaw has teeth where most snakes do not. The snake's teeth are also all hinged at the base, rather than more firmly attached to the jaw bone, so they can wiggle back and forth a bit without falling out.

Adults usually reach about 2 to 3 feet (0.6 to 0.9 meters) in length. The tail makes up about one-tenth of the body's total length. In snakes, the tail begins at the vent, a slitlike opening on the belly side.