Rena humilis humilis - Southwestern Threadsnake

Nonvenomous

Considered harmless to humans.

Size

Adults 7 - 16 inches long (18-41 cm). Hatchlings are around 4 - 5 inches long.

Appearance

A very thin snake with a blunt head and tail. The tail is tipped with a small spine. Eyes are nonfunctional dark spots visible under translucent plates. The scales are shiny and cycloid. Belly plates are not enlarged. The lower jaw is countersunk.

Coloring is brown, purple, or pink. This snake can be mistaken for a large worm.

Behavior and Natural History

When hunting for food, burrows under roots, rocks, and into ants nests. Often found under rocks, boards, or other surface debris where the soil is slightly moist. Sometimes found crawling on roads at night.

When threatened, this snake often writhes around, forming a tight coil while releasing pungent fluids from the cloaca. These fluids serve to repel defensive attacks by the ants and termites on which it feeds.

Diet

Eats ants and termites and their larvae and pupae, and occasionally other small insects.

Reproduction

Mates in the spring, lays eggs July - August. Females tend to the eggs, and may use communal nests.

Range

This species, Rena humilis humilis - Southwestern Threadsnake, occurs along the Southern California coast, the east, north of the range of R.h.cahuilae, into southern Nevada and western Arizona, and south along the west coast of Baja California.

The species Rena humilis - Western Threadsnake, is found from Southern California east through southern Arizona and New Mexico, into southwestern Texas, and south into Mexico and Baja California, Mexico.

Habitat

Inhabits areas where the soil is suitable for burrowing: brushy mountain slopes, deserts, rocky hillsides, washes near streams, beach sand.

Taxonomic Notes

Some herpetologists do not recognize subspecies of Rena humilis. Those who do recognize four subspecies in the United States, and five in Mexico.

In 2009, Adalsteinsson, Branch, Trape, Vitt & Hedges (Molecular Phylogeny, Classification, and Biogeograpy of Snakes of the Family Leptotyphlopidae (Reptilia, Squamata). Zootaxa. 2240: pp. 1 - 50) placed this species in the genus Rena, making it Rena cahuilae.

Conservation Issues (Conservation Status) None.