Lyre Snake

(Trimorphodon biscutatus)

Color Photographs: Chris Brown, U.S. Geological Survey

Lyre Snake (Trimorphodon biscutatus)

Identification: Snake 18 to 48 inches in length. Eye pupil narrow, vertical, so called "cat's eye") in shape. Head broad, contrasting with a relatively narrow neck. Back of the head usually with a prominent dark brown chevron and triangle. Body light brown to gray. Back with brown blotches, continued by thin lines down the sides and with a central lighter crossbar in the center. Belly yellow to cream-white. Scales smooth and anal plate either single or divided.

Geographical Variation:

Baja California Lyre Snake (T. b. lyrophanes): Back of head with prominent dark brown chevron and inner triangle; 21 to 43 dorsal blotches. Range: Southern California except for the southeastern part of the state, southward into Northern Baja California.

Sonoran Lyre Snake (T. b. lambda): Back of the head with prominent dark brown chevron and inner triangle; fewer than 34 dorsal blotches. Range: Southeastern California westward to southwestern New Mexico, and northward into extreme southern Nevada and Utah. Extends southward throughout much of Sonora.

Texas Lyre Snake (T. b. vilkonsinii): Back of head without either a prominent dark brown chevron or an inner triangle; 17 to 24 dorsal blotches. Range: Western Texas and northern Chihuahua, and northward into central New Mexico.

Range (see map on left): The Lyre Snake is found in the southwestern United States and southward into Mexico. It occupies southern California, southern Arizona, southern New Mexico, and westward into west Texas.

Habitat: This species occurs in a variety of western habitats including grasslands, chaparral, desert scrubland, pinyon-juniper, and oak woodlands. It is most commonly found in rocky habitats at relatively low elevations.

Food: Lizards, birds, and small mammals.

Behavior: The Lyre Snake is most often associated with rocks, commonly hiding among crevices during the day, and emerging by night. The enlarged teeth at the back of the jaw secrete a poison.

Reproduction:  Poorly known. Clutches of 7 and 20 eggs have been reported.

Lyre Snake (Trimorphodon biscutatus)

Similar Species:

Gopher Snake (Pituophis catenifer)

Night Snake (Hypsiglena torquata)

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