Neotropical Sunbeam Snake: Loxocemidae

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NEOTROPICAL SUNBEAM SNAKE: Loxocemidae

PHYSICAL CHARACTERISTICS

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.

GEOGRAPHIC RANGE

This snake lives from southwestern Mexico through much of Central America, including Guatemala, El Salvador, Honduras, Nicaragua, and northwestern Costa Rica.

HABITAT

Neotropical sunbeam snakes live in warm climates and a variety of forested areas, but not in the mountains. They also sometimes make their home along the beaches of the coastline. They are secretive animals that hide among rocks and leaves, beneath logs and/or under their bark, in below-ground holes, and even in ant nests.

DIET

This snake will eat small mammals and adult and young lizards, including whip-tailed lizards. It also eats the eggs of black and green iguanas and olive Ridley seaturtles. The snake apparently crawls into the lizard and turtle nests, wraps its body around the eggs, then moves in with its head to swallow them whole. In captivity, the snakes will sometimes bite into the eggs, but then swallow the entire egg. A snake may eat several eggs, sometimes more than two dozen, at one time.

WHAT IS CITES?

CITES is the Convention on International Trade in Endangered Species of Wild Fauna and Flora. Governments from all over the world volunteer to participate in CITES to control the buying and selling, called trade, of plants and animals from one country to the next. This is especially important for species that are threatened with extinction or otherwise in danger, because such collecting could possibly wipe out an entire species. CITES protects these plants and animals by listing each species under one of three sets of rules that control or ban almost all trade of animals. Currently, CITES protects about five thousand species of animals, including the neotropical sunbeam snake, and twenty-eight thousand species of plants.

BEHAVIOR AND REPRODUCTION

Because this snake spends a good deal of its time underground, scientists know little about the details of its behavior in the wild but have learned some information from captive snakes, which are held in various zoos around the world. They are called semi-fossorial (SEM-ee-faw-SOR-ee-ul) animals. "Fossorial" means that they spend time below ground, and adding "semi" points out that they frequently leave their underground homes. During the daytime, the snakes stay out of sight by using their upward-curved snouts to push through leaves to reach the ground, where they dig into loose dirt to make tunnels, or burrows. They come out at night and on rainy days to wander around above ground looking for things to eat. The white speckles on the backs of adults likely provide some camouflage. Like many other animals, the pattern on the skin breaks up the outline of their bodies and makes it more difficult for predators (PREH-duh-ters), or animals that hunt other animals for food, to spot them against the background habitat. For example, a completely dark snake slithering over a pile of leaves would be more noticeable than a snake with lighter patches that hide its outline.

The neotropical sunbeam snake finds its food by following scent trails or by simply spotting a mammal, lizard, or an egg. It is a constrictor (kun-STRIK-tuhr), which means that it coils its body around the animal it wants to eat, then tightens the coil until the animal passes out or dies. It then releases the coil, slides its head around, and eats the prey. As noted, it wraps its body around eggs but does not crush them.

During breeding season, male neotropical sunbeam snakes fight over females, sometimes biting one another in quite vicious battles. The males have sharp spurs near the vent. These spurs can apparently cut the female quite deeply during mating. About two months after mating, captive females commonly lay from two to four eggs at a time, although they can lay eight or more. Baby snakes in the wild hatch in May. When they reach four to five years old, they can begin to have their own babies.

NEOTROPICAL SUNBEAM SNAKES AND PEOPLE

This is not a typical pet species, probably because of its tendency to spend much of its time underground. The Convention on International Trade in Endangered Species (CITES) lists this species as one that people cannot freely buy and sell.

CONSERVATION STATUS

This species is not listed as endangered or threatened.

FOR MORE INFORMATION

Books

Burnie, David, and Don Wilson, eds. The Definitive Visual Guide to the World's Wildlife. New York: DK Publishing, 2001.

Greene, H. W. Snakes: The Evolution of Mystery in Nature. Berkeley: University of California Press, 1997.

McDiarmid, R. W., J. A. Campbell, and T. Touré. Snake Species of the World. Vol. 1. A Taxonomic and Geographic Reference. Washington, DC: The Herpetologists' League, 1999.

Savage, J. M. The Amphibians and Reptiles of Costa Rica. Chicago: University of Chicago Press, 2002.

Wilson, L. D., and J. R. Meyer. The Snakes of Honduras. 2nd ed. Milwaukee: Milwaukee Public Museum, 1985.

Web sites

"New World Sunbeam Snake." Vida Preciosa International Inc. http://www.vpi.com/5VPIBreeders/NewWorldSunbeamSnake/NewWorldSunbeamSnake.htm (accessed on September 11, 2004).

"Mexican Burrowing Python, Loxocemus." Glasgow Zoopark. http://www.glasgowzoo.co.uk/articles/coldblooded/mexburrowingpyth.php (accessed on September 11, 2004).

"Mexican Burrowing Snake." Utah's Hogle Zoo. http://www.hoglezoo.org/animals/view.php?id=42 (accessed on September 11, 2004).