The Texas lyre snake is a subspecies

Subspecies

Subspecies in biological classification, is either a taxonomic rank subordinate to species, ora taxonomic unit in that rank . A subspecies cannot be recognized in isolation: a species will either be recognized as having no subspecies at all or two or more, never just one...

 of mildly venomous

Venomous snake

"Poisonous snake" redirects here. For true poisonous snakes, see Rhabdophis.Venomous snakes are snakes which have venom glands and specialized teeth for the injection of venom...

 rear-fanged colubrid

Colubrid

A colubrid is a member of the snake family Colubridae. This broad classification of snakes includes about two-thirds of all snake species on earth. The earliest species of the snake family date back to the Oligocene epoch. With 304 genera and 1,938 species, Colubridae is the largest snake family...

. The epithet vilkinsonii is in honor of amateur American naturalist Edward Wilkinson, who collected the first specimen near the city of Chihuahua.^{http://ebeltz.net/herps/biogappx.html} Some sources consider it to be its own species (Trimorphodon vilkinsonii).

Geographic range

It is found in the United States

United States

The United States of America is a federal constitutional republic comprising fifty states and a federal district...

 in the Big Bend region of Texas

Texas

Texas is the second largest U.S. state by both area and population, and the largest state by area in the contiguous United States.The name, based on the Caddo word "Tejas" meaning "friends" or "allies", was applied by the Spanish to the Caddo themselves and to the region of their settlement in...

 and southern New Mexico

New Mexico

New Mexico is a state located in the southwest and western regions of the United States. New Mexico is also usually considered one of the Mountain States. With a population density of 16 per square mile, New Mexico is the sixth-most sparsely inhabited U.S...

, and in Mexico

Mexico

The United Mexican States , commonly known as Mexico , is a federal constitutional republic in North America. It is bordered on the north by the United States; on the south and west by the Pacific Ocean; on the southeast by Guatemala, Belize, and the Caribbean Sea; and on the east by the Gulf of...

 in northeastern Chihuahua.

Description

They are medium-sized snakes, attaining lengths of approximately 1 meter (39 inches) at adult size. They are brown, tan or gray with 17-24 dark brown blotches down the back. They have large eye

Eye

Eyes are organs that detect light and convert it into electro-chemical impulses in neurons. The simplest photoreceptors in conscious vision connect light to movement...

s with vertical pupil

Pupil

The pupil is a hole located in the center of the iris of the eye that allows light to enter the retina. It appears black because most of the light entering the pupil is absorbed by the tissues inside the eye. In humans the pupil is round, but other species, such as some cats, have slit pupils. In...

s. The common name, lyre snakes, comes from a distinctive V shaped pattern on the head which resembles the shape of a lyre

Lyre

The lyre is a stringed musical instrument known for its use in Greek classical antiquity and later. The word comes from the Greek "λύρα" and the earliest reference to the word is the Mycenaean Greek ru-ra-ta-e, meaning "lyrists", written in Linear B syllabic script...

. However, it should be noted that this particular subspecies (T. b. vilkinsonii) has no V mark on the head.

Behavior

Lyre snakes are nocturnal

Nocturnal animal

Nocturnality is an animal behavior characterized by activity during the night and sleeping during the day. The common adjective is "nocturnal"....

, spending most of their time hiding in rock crevices, emerging to feed mainly on lizard

Lizard

Lizards are a widespread group of squamate reptiles, with nearly 3800 species, ranging across all continents except Antarctica as well as most oceanic island chains...

s, and also on small rodent

Rodent

Rodentia is an order of mammals also known as rodents, characterised by two continuously growing incisors in the upper and lower jaws which must be kept short by gnawing....

s, frog

Frog

Frogs are amphibians in the order Anura , formerly referred to as Salientia . Most frogs are characterized by a short body, webbed digits , protruding eyes and the absence of a tail...

s, bat

Bat

Bats are mammals of the order Chiroptera "hand" and pteron "wing") whose forelimbs form webbed wings, making them the only mammals naturally capable of true and sustained flight. By contrast, other mammals said to fly, such as flying squirrels, gliding possums, and colugos, glide rather than fly,...

s and birds. Their venom is not considered to be harmful to humans. Also, if their venom is not fatal to their prey, they may kill by constriction.