Sonoran Lyresnake
Trimorphodon lambda
A slender, big-eyed nocturnal snake named for the lyre-shaped mark on its head, with rear fangs used to subdue small prey.
- Venomous?
- Mildly venomous
- Adult length
- 50-90 cm (20-35 in)
- Range
- Southwestern United States (Arizona) and northwestern Mexico
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Overview
The Sonoran Lyresnake is a slender, nocturnal colubrid found in rocky desert habitats of the American Southwest and northwestern Mexico. It is named for the lyre- or V-shaped marking on top of its head.
It possesses mildly venomous rear-positioned fangs used to subdue small prey, though it is not considered dangerous to humans.
How to identify it
- Slender body with tan to gray ground color and dark brown or gray crossbands or blotches
- Distinctive lyre- or V-shaped dark marking on top of the head
- Large, vertically elliptical pupils, unusual for a colubrid, reflecting its nocturnal habits
- Smooth scales; relatively large head compared to slender neck
- Distinguished from gophersnakes by its elliptical pupils and lyre-shaped head marking
Habitat & range
Found in rocky canyons, cliffs, and desert foothills, often near boulder piles and rock crevices that provide daytime shelter.
Behavior, diet & reproduction
Strictly nocturnal, emerging at night to hunt lizards, small mammals, and bats from crevices. Uses mildly venomous rear fangs delivered through a chewing bite to subdue prey. Lays eggs in summer.
Frequently asked questions
Is the Sonoran Lyresnake dangerous to humans?
It is only mildly venomous, using its rear fangs on small prey, and is not considered dangerous to people.
Why does it have vertical pupils?
Its elliptical pupils are an adaptation for nocturnal hunting, allowing better vision in low light.
What is the lyre-shaped mark?
It refers to a distinctive V- or lyre-shaped dark marking on top of the head that gives the species its common name.
Where does it live?
In rocky canyons and desert foothills, especially near boulders and rock crevices in Arizona and northwestern Mexico.
Sonoran Lyresnake guides
In-depth guides for identifying and understanding Sonoran Lyresnake.
