EARLY BLIND SNAKES: Anomalepididae

PHYSICAL CHARACTERISTICS

Early blind snakes are small, thin snakes, with many species reaching just 6 to 10 inches (15 to 25 centimeters) in length and less than one-tenth of an ounce (2.8 grams) in weight when full-grown. Five of the sixteen species are a bit larger and can top 12 inches (31 centimeters) in length, with some reaching as much as 16 inches (41 centimeters). The larger species include the greater blind snake and the four lesser blind snakes known by their scientific names. Most members of this family Anomalepididae have no common names and are known only by their scientific names. The typical early blind snake has a dark brown or black body with white, yellow, or pink on the head and tail. A few species lack the lighter color on the head and tail and are all reddish brown to brown.

The snakes in this family all have short heads with rounded snouts, and most have slightly larger scales on the snout than on the rest of the body. Compared to other snakes, their tongues are quite short. They have stumpy tails that make up just 1 to 3.4 percent of the snake's total body length. In snakes, the tail begins at the vent, a slitlike opening on the belly side of the animal. The tail in half of the early blind snake species is tipped with a thin, sharp spine. The other species have tails without spines.

They look much like slender blind snakes of the family Leptotyphlopidae and blind snakes of the family Typhlopidae. The snakes in all three families have tube-shaped bodies that are covered in smooth, round scales. Unlike most snakes that have belly scales, or ventrals, that are noticeably larger than the scales on the sides and back, the members of these three families have belly scales that are about the same size as the others. The three families also share a few other traits. All have small mouths that open not on the front end of the head as in most other snakes, but slightly before the front end and on the bottom. They have tiny eyes that are barely noticeable, if they are noticeable at all, beneath scales on the head.

Early blind snakes do have some differences from the other two blind snake families. Early blind snakes have teeth on both the upper and lower jaws, while snakes in the other families have them only on the upper jaw or only on the lower jaw. In addition, early blind snakes have more scale rows than the others. Scientists determine scale rows by counting the number of scales from the belly up the side over the top and down the other side. Most early blind snakes have more than 20 scale rows.

Early blind snakes sometimes go by the common names of primitive or dawn blind snakes. Because many individuals have a head and tail that are very hard to tell apart, they are also sometimes called two-headed snakes.

TANGLED FAMILIES

Although some sources lump the blind snakes together in one family, most scientists place them in three separate families: the blind snakes of the family Typhlopidae, the early blind snakes of the family Anomalepididae, and the slender blind snakes of the family Leptotyphlopidae. The early blind snakes first got their own family in 1939 when Edward H. Taylor noticed several differences in them from other blind snakes, including a greater number of scale rows and the presence of teeth on both jaws instead of just one or the other. They also have an unusually shaped bone, called the hyoid (HIGH-oid), that supports the tongue. In early blind snakes, it is M-shaped, rather than the typical V- or Y-shape seen in other snakes.

GEOGRAPHIC RANGE

Early blind snakes live in southern Central America, across northern South America and possibly on Trinidad, and then down the eastern side of South America to northeastern Argentina. Of the four main groups, or genera (jen-AIR-uh), in this family, two live from Costa Rica to northern South America. These include the four species in the genus (JEAN-us) (the singular of genera) Anomalepis and the three species in the genus Helminthophis. The two species of the genus Typhlophis live only in South America, from central Venezuela eastward through French Guiana and southward through northeastern Brazil. One species may extend onto Trinidad. The largest genus is Liotyphlops with eight species. Some of these live from Costa Rica into northern South America, and others make their homes farther south in southern Brazil, southeastern Paraguay, and northeastern Argentina.

One species, Helminthophis flavoterminatus, lives on the Indian Ocean island of Mauritius, far away from the other early blind snakes. Humans are likely responsible for bringing the snake to the island.

HABITAT

These snakes live most of their lives below the ground; one individual was reported buried 1.6 feet (0.5 meters) deep in the soil. They also spend time beneath rocks, logs, and piles of leaves. Like other underground-living, or fossorial (faw-SOR-ee-ul), species that stay out of human sight and live in remote areas, scientists know little about them. People have reported these snakes in a number of different habitats from dry forests to rainforests, and from low-lying grasslands to nearly 6,000 feet (1,830 meters) up rocky mountainsides. Although no one has seen early blind snakes doing it, scientists suspect that they can and do climb trees.

DIET

At least two species eat ant eggs, as well as ant larvae (LAR-vee) and pupae (PEW-pee), which are the life stages between the egg and the adult ant. Scientists suspect that other early blind snakes also eat ants and possibly other insects, but they have not studied them in enough detail to say for sure.

BEHAVIOR AND REPRODUCTION

Scientists know little about their behavior in the wild but suspect that they remain active all year and mainly at night. In captivity, the snakes stay underground most of the time. When picked up by a person, an early blind snake defends itself by squirming and twisting its body and then releasing body waste —both of which may cause the person to lose grip or let go of the snake. If it has a spine-tipped tail, the snake will also jab it into the person's hand.

Snake researchers guess that the early blind snakes probably lay eggs rather than give birth to live babies, but they have not studied them enough to be sure. No information is available on when or how the snakes mate or on how many young they have.

EARLY BLIND SNAKES AND PEOPLE

Early blind snakes and people rarely encounter one another.

CONSERVATION STATUS

These species are not listed as endangered or threatened. Like many other species that live much of their lives underground, however, scientists have little information about their numbers in the wild. In fact, scientists know about six of the sixteen species only from a few individuals caught in the area where the first ones were found, and they have not seen one species, the South American blind snake (Anomalepis aspinosus), since 1916.

LESSER BLIND SNAKE (Liotyphlops ternetzii): SPECIES ACCOUNT

Physical characteristics: One of the larger members of the family, lesser blind snake adults can grow to more than 12 inches (31 centimeters) in length. It is a thin, black, wormlike snake with white on its head. Its shiny body is covered with small scales that are all about the same size. It has tiny eyes and a small mouth that opens on the bottom of the head rather than in front like the mouths in most other snakes. Its body is tube-shaped and ends with a short spine-tipped tail. Its skeleton includes bits of hip bones that are leftover reminders of its ancient ancestors, which had legs.

Geographic range: The lesser blind snake lives in Central and South America.

Habitat: This species spends most of its time underground, beneath rocks or logs, or in other hiding places.

Diet: They eat ant eggs, larvae, and pupae. The larvae and pupae are the life stages between the egg and the adult ant. They may also eat other insects.

Behavior and reproduction: Scientists know almost nothing about their behavior and reproduction. They suspect, however, that these snakes are active at night throughout the year and that they lay eggs.

Lesser blind snakes and people: Lesser blind snakes and people rarely encounter one another.

Conservation status: The species is not listed as endangered or threatened, but scientists have little information about their numbers in the wild. ∎

FOR MORE INFORMATION

Books

Brazaitis, P., and M. Watanabe. Snakes of the World. New York: Crescent Books, 1992.

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

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

Mehrtens, John M. Living Snakes of the World in Color. New York: Sterling Publishing. 1987.

Peters, James A., and Braulio R. Orejas-Miranda. Catalogue of the Neotropical Squamata. Vol. 1, Snakes. Washington, DC: Smithsonian Institution Press, 1970.

Taylor, Barbara. Snakes. New York: Lorenz: 1998.

Web sites

"Blind snake (Typhlopidae)." MavicaNET. http://www.mavicanet.ru/directory/eng/24710.html (accessed on October 5, 2004).

"Blindsnakes (Infraorder Scolecophidia)." Singapore Zoological Gardens. http://www.szgdocent.org/cc/c-blind.htm (accessed on September 29, 2004).

"Family Anomalepidae (Dawn Blind Snakes)." EMBL Reptile Database. http://www.embl-heidelberg.de/uetz/families/Anomalepidae.html (accessed on October 5, 2004).

"Superfamiliy Typhlopoidea (blind snakes)." The University of Michigan Museum of Zoology, Animal Diversity Web. http://animaldiversity.ummz.umich.edu/site/accounts/pictures/Typhlopoidea.html (accessed on October 5, 2004).