Trimorphodon lyrophanes - California Lyresnake

Mildly Venomous

One of the larger rear-fanged snakes, but considered harmless to humans, but handle with caution, as some people have had unpleasant reactions to this snake's bite.

Size

Trimorphodon have been recorded from 18 - 47 3/4 inches in length (46 - 121 cm). Most snakes encountered are 24 - 36 inches long (61 - 91 cm).

Appearance

A slender snake with a broad head well-differentiated from the slim neck. Coloring closely matches a snake's rocky habitat, from gray to light brown. There are usually about 35 dorsal blotches with light edges and a pale crossbar in the center, and smaller irregular blotches on the lower sides. A lyre-shaped marking is present on top of the head. The pupils are vertical, like those of a cat. The underside is off-white or yellowish with dark spots. The anal plate is usually undivided.
According to Stebbins there is a dark form of this snake with a light brown middorsal stripe found at the Pisgah lava flow.

Behavior

Nocturnal, active in very dry conditions as well as during rains. Terrestrial, and good climbers. This snake often searches rock crevices for prey. It can be found during the day inside crevices in large rock outcrops, as well as crossing desert roads at night.

Diet

Primarily lizards, but also known to eat small mammals, nestling birds, and snakes.

Reproduction

Not well known. Lyre snakes apparently originated in the tropics, where breeding is year round, and the northern races may have retained this capability.

Range

In California, this snake occurs from around Santa Barbara County northeast into Inyo County, and south along the coast into Baja California, in two strips through the peninsular ranges, and along the Colorado River, splitting around the Imperial Valley. It is also absent from a large area of the Mojave Desert except for isolated localities including the Pisgah lava flow area. This may be due to the secretive nature of this snake. It may be more widespread in this area.

Habitat

Associated primarily with rocky locations in desert scrub and grassland, chaparral, oak woodland, coniferous forest, but found in rockless areas, also.

Taxonomic Notes

Devitt et al, in a 2008 paper*, recommended that the subspecies of Trimorphodon biscutatus - lambda, lyrophanes, and vilkinsonii, be recognized as distinct species - Trimorphodon lambda, Trimorphodon lyrophanes, and Trimorphodon vilkinsonii.

*Thomas J. Devitt, Travis J. LaDuc & Jimmy A. McGuire. (2008. The Trimorphodon biscutatus (Squamata: Colubridae) Species Complex Revisited: A Multivariate Statistical Analysis of Geographic Variation. Copeia. 2008(2): 370-387) Conservation Issues (Conservation Status) None.