Common names: rock rattlesnake, green rattlesnake, blue rattlesnake, more.

Crotalus lepidus is a 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...

 pitviper

Crotalinae

The Crotalinae, commonly known as "pit vipers" or crotaline snakes, are a subfamily of venomous vipers found in Asia and the Americas. They are distinguished by the presence of a heat-sensing pit organ located between the eye and the nostril on either side of the head...

 species

Species

In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...

 found in the southwestern United States

United States

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

 and northern central 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...

. Four 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...

 are currently recognized, including the nominate subspecies described here.

Description

This is a small species that rarely exceeding 32" in length. They have a large, rounded head, and fairly heavy body for their size, with 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 that have 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. Like other rattlesnakes, their tail has a rattle on it, which is composed of keratin

Keratin

Keratin refers to a family of fibrous structural proteins. Keratin is the key of structural material making up the outer layer of human skin. It is also the key structural component of hair and nails...

. Each time the snake sheds its skin, a new segment is added to the rattle, but the rattle is fragile and may break off, and the frequency of shedding can vary, so the snake's age cannot be determined by its length or number of segments.

The color pattern varies greatly, but generally reflects the color of the rock in their natural environment. Snakes found near areas that are predominantly limestone

Limestone

Limestone is a sedimentary rock composed largely of the minerals calcite and aragonite, which are different crystal forms of calcium carbonate . Many limestones are composed from skeletal fragments of marine organisms such as coral or foraminifera....

 tend to be a light grey

Grey

Grey or gray is an achromatic or neutral color.Complementary colors are defined to mix to grey, either additively or subtractively, and many color models place complements opposite each other in a color wheel. To produce grey in RGB displays, the R, G, and B primary light sources are combined in...

 in color, with darker grey banding. Snakes found at higher altitudes have darker colors. Specimens of the mottled rock rattlesnake (C. l. lepidus) from the Davis Mountains

Davis Mountains

The Davis Mountains are a range of mountains in West Texas, located near Fort Davis, after which they are named. They are a popular site for camping and hiking and the region includes Fort Davis National Historic Site and Davis Mountains State Park...

 region often exhibit a more pink

Pink

Pink is a mixture of red and white. Commonly used for Valentine's Day and Easter, pink is sometimes referred to as "the color of love." The use of the word for the color known today as pink was first recorded in the late 17th century....

 coloration, with dark grey speckling rather than distinct banding.^{http://www.designeratrox.com/lepidus.html} The banded rock rattlesnake (C. l. klauberi) gets its common name from its distinctive, clean banding, often with little speckling or mottling.

Common names

Blue rattlesnake, Eastern rock rattlesnake, green rattlesnake, little green rattlesnake, pink rattlesnake, rock rattlesnake, Texas rock rattlesnake, white rattlesnake.

Geographic range

Found in the southwestern United States

United States

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

 (Arizona

Arizona

Arizona ; is a state located in the southwestern region of the United States. It is also part of the western United States and the mountain west. The capital and largest city is Phoenix...

, 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 southwestern 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 northern central 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...

. The type locality given is "Presidio del Norte and Eagle Pass" (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...

, USA

United States

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

). H.M. Smith and Taylor (1950) emended the type locality to "Presidio (del Norte), Presidio County, Texas."

Conservation status

This species is classified as Least Concern (LC) on the IUCN

World Conservation Union

The International Union for Conservation of Nature and Natural Resources is an international organization dedicated to finding "pragmatic solutions to our most pressing environment and development challenges." The organization publishes the IUCN Red List, compiling information from a network of...

 Red List of Threatened Species

IUCN Red List

The IUCN Red List of Threatened Species , founded in 1963, is the world's most comprehensive inventory of the global conservation status of biological species. The International Union for Conservation of Nature is the world's main authority on the conservation status of species...

 (v3.1, 2001). Species are listed as such due to their wide distribution, presumed large population, or because it is unlikely to be declining fast enough to qualify for listing in a more threatened category. The population trend is stable. Year assessed: 2006.

However, it is listed as a threatened species

Threatened species

Threatened species are any speciesg animals, plants, fungi, etc.) which are vulnerable to endangerment in the near future.The World Conservation Union is the foremost authority on threatened species, and treats threatened species not as a single category, but as a group of three categories,...

 by the US state of 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...

, although the state 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...

 does not protect it. Its habitat is largely inaccessible, and not currently threatened by human development, though it is gradually becoming more and more fragmented.

Behavior

In general, these snakes are not aggressive. They tend to rely heavily on their camouflage

Camouflage

Camouflage is a method of concealment that allows an otherwise visible animal, military vehicle, or other object to remain unnoticed, by blending with its environment. Examples include a leopard's spotted coat, the battledress of a modern soldier and a leaf-mimic butterfly...

, and will often not strike or even rattle their tails unless physically harassed. They spend most of their life in rocky outcroppings and talus

Scree

Scree, also called talus, is a term given to an accumulation of broken rock fragments at the base of crags, mountain cliffs, or valley shoulders. Landforms associated with these materials are sometimes called scree slopes or talus piles...

 slopes, which is where they get their name from. Man-made road cuts are often a favorite place. They are primarily nocturnal.

Feeding

Their diet consists of small mammal

Mammal

Mammals are members of a class of air-breathing vertebrate animals characterised by the possession of endothermy, hair, three middle ear bones, and mammary glands functional in mothers with young...

s, 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 sometimes 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. They are often more active at colder temperatures than other rattlesnake species.

Captivity

Two 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...

, C. l. lepidus and C. l. klauberi

Crotalus lepidus klauberi

Crotalus lepidus klauberi is a venomous pitviper subspecies found in the southern United States, in Arizona, New Mexico and Texas, and northern Mexico, including the states of Baja California, Sonora, Chihuahua, Coahuila, Nuevo Leon, Tamaulipas, Durango, Zacatecas, San luis Potosi and Jalisco...

, are frequently available in the exotic animal trade, and are well represented in zoo

Zoo

A zoological garden, zoological park, menagerie, or zoo is a facility in which animals are confined within enclosures, displayed to the public, and in which they may also be bred....

s around the world. They are sought after for their wide array of potential colorations, and typically docile nature. Most available are wild caught; captive breeding, while not unheard of, is not commonplace. The two subspecies found only in Mexico are not often found in captivity outside of Mexico.

Reproduction

These snakes are ovoviviparous

Ovoviviparity

Ovoviviparity, ovovivipary, or ovivipary, is a mode of reproduction in animals in which embryos develop inside eggs that are retained within the mother's body until they are ready to hatch...

. They breed once a year, in the spring, and give birth approximately 4 months later to 6-8 young. The young generally look like miniature versions of the parents and take 3 or more years to mature.

Venom

The venom is primarily a haemotoxin

Hemotoxin

Hemotoxins, haemotoxins or hematotoxins are toxins that destroy red blood cells , disrupt blood clotting, and/or cause organ degeneration and generalized tissue damage. The term hemotoxin is to some degree a misnomer since toxins that damage the blood also damage other tissues...

, but has been known to have significant neurotoxic

Neurotoxin

A neurotoxin is a toxin that acts specifically on nerve cells , usually by interacting with membrane proteins such as ion channels. Some sources are more general, and define the effect of neurotoxins as occurring at nerve tissue...

 effects as well. While not type specific, the polyvalent

Polyvalent

In chemistry, polyvalence or multivalence refers to species that are not restricted to a distinct number of valence bonds....

 antivenin

Antivenin

Antivenom is a biological product used in the treatment of venomous bites or stings. Antivenom is created by milking venom from the desired snake, spider or insect. The venom is then diluted and injected into a horse, sheep or goat...

 CroFab

CroFab

CroFab is the commercial name for a Crotalidae Polyvalent Immune Fab snake antivenom, indicated for minimal or moderate North American Crotalid snake envenomation. It is developed and manufactured by BTG plc , and distributed in the US by Nycomed Inc...

 is generally used to treat serious envenomations.

Subspecies

Subspecies	Taxon author	Common name	Geographic range
C. l. klauberi Crotalus lepidus klauberi Crotalus lepidus klauberi is a venomous pitviper subspecies found in the southern United States, in Arizona, New Mexico and Texas, and northern Mexico, including the states of Baja California, Sonora, Chihuahua, Coahuila, Nuevo Leon, Tamaulipas, Durango, Zacatecas, San luis Potosi and Jalisco...	Gloyd, 1936	Banded Rock Rattlesnake	Arizona Arizona Arizona ; is a state located in the southwestern region of the United States. It is also part of the western United States and the mountain west. The capital and largest city is Phoenix... , 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... , 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... , 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...  (south to Jalisco Jalisco Jalisco officially Estado Libre y Soberano de Jalisco is one of the 31 states which, with the Federal District, comprise the 32 Federal Entities of Mexico. It is located in Western Mexico and divided in 125 municipalities and its capital city is Guadalajara.It is one of the more important states... )
C. l. lepidus	Kennicott Robert Kennicott Robert Kennicott was an American naturalist.-Biography:Kennicott was born in New Orleans and grew up in "West Northfield" , Illinois, a town in the prairie north of the then nascent city of Chicago.... , 1861	Mottled Rock Rattlesnake	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... , 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... , 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...  (Chihuahua)
C. l. maculosus	Tanner, Dixon James R. Dixon Dr. James Ray Dixon is Professor Emeritus and Curator Emeritus of Amphibians and Reptiles at the Texas Cooperative Wildlife Collection at Texas A&M University. His main research focus has been the natural history of Texas amphibians and reptiles and he has authored numerous field guides and...  & Harris, 1972	Durango Rock rattlesnake	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...  (Durango Durango Durango officially Estado Libre y Soberano de Durango is one of the 31 states which, with the Federal District, comprise the 32 Federal Entities of Mexico. The state is located in Northwest Mexico. With a population of 1,632,934, it has Mexico's second-lowest population density, after Baja... , Sinaloa Sinaloa Sinaloa officially Estado Libre y Soberano de Sinaloa is one of the 31 states which, with the Federal District, comprise the 32 Federal Entities of Mexico. It is divided in 18 municipalities and its capital city is Culiacán Rosales.... , Nayarit Nayarit Nayarit officially Estado Libre y Soberano de Nayarit is one of the 31 states which, with the Federal District, comprise the 32 Federal Entities of Mexico. It is divided in 20 municipalities and its capital city is Tepic.It is located in Western Mexico... , Jalisco Jalisco Jalisco officially Estado Libre y Soberano de Jalisco is one of the 31 states which, with the Federal District, comprise the 32 Federal Entities of Mexico. It is located in Western Mexico and divided in 125 municipalities and its capital city is Guadalajara.It is one of the more important states... )
C. l. morulus	Klauber Laurence Monroe Klauber Laurence M. Klauber , was an American herpetologist, and was considered to be the foremost authority on rattlesnakes... , 1952	Tamaulipan Rock rattlesnake	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...  (Sierra Madre Oriental Sierra Madre Oriental The Sierra Madre Oriental is a mountain range in northeastern Mexico.-Setting:Spanning the Sierra Madre Oriental runs from Coahuila south through Nuevo León, southwest Tamaulipas, San Luis Potosí, Querétaro, and Hidalgo to northern Puebla, where it joins with the east-west running Eje Volcánico... )

External links

• Rock rattlesnake at Chihuahuan Desert Museum and Gardens. Accessed 12 December 2007.
• Crotalus lepidus at University of Texas. Accessed 12 December 2007.
• Mottled rock rattlesnake at kingsnake.com. Accessed 12 December 2007.