Neotropical Sunbeam Snake: Loxocemidae

This family has only one species, the neotropical sunbeam snake. It also is known as a Mexican burrowing python, New World python, ground python, dwarf python, and burrowing boa, but it is actually neither a boa nor a python. Boas and pythons are in separate families. For many years, some researchers felt this snake was similar enough to the boas that it should be placed in the Boidae family, but now most agree that it should have its own family, as it does in this chapter.

The neotropical sunbeam snake has a small mouth, tiny cateyed pupils, and a somewhat-pointed, upturned snout. Its head is covered with larger scales than the rest of the upper body. The belly side of the snake is whitish, while the upper snake is brown, sometimes with small, white speckles. This obvious shift from the brown back to the white underside gives the snake its scientific name bicolor ("bi" meaning two). Its scales are slightly iridescent (IH-rih-DEH-sent), which means that they change color depending on how light bounces off them. Often, the neotropical sunbeam snake is confused with another family of snakes that lives in southeast Asia. The southeast Asian sunbeam snakes have iridescent scales much like those on the neotropical sunbeam snakes. One feature that helps to tell them apart is the presence of pelvic spurs, which are tiny bits of bone that stick out from the underside of neotropical sunbeam snakes near the vent, which is the slitlike opening on the belly side between the middle and end of the snake. Asian sunbeam snakes do not have spurs. Male neotropical sunbeam snakes have two noticeable pelvic spurs. Females also have spurs, but they are small and difficult to see. Young snakes look like smaller versions of the adults. They have the slightly iridescent, copper-colored skin, but they do not have any white speckles on their backs.

Neotropical sunbeam snakes have heavy muscular bodies. Adults usually are less than 3 feet (1 meter) long, but large ones can reach 5 feet (1.5 meters) in length. The short tail makes up only about 10 to 14 percent of its total body length. As in all snakes, the tail begins at the vent.