Common names: Middle American rattlesnake, Central American rattlesnake,, Tzabcan (local name for subspecies C. s. tzabcan).

Crotalus simus 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 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...

 and Central America

Central America

Central America is the central geographic region of the Americas. It is the southernmost, isthmian portion of the North American continent, which connects with South America on the southeast. When considered part of the unified continental model, it is considered a subcontinent...

. The specific epithet is Latin for "flat nosed"; likely an allusion to the fact that its head is relatively blunt when compared with the lanceheads (Bothrops

Bothrops

Bothrops is a genus of venomous pitvipers found in Central and South America. The generic name is derived from the Greek words bothros and ops that mean "pit" and "eye" or "face"; an allusion to the heat-sensitive loreal pit organs. Members of this genus are responsible for more human deaths in the...

). Currently, 3 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 recognized, including the nominate subspecies described here.

Description

Adults commonly exceed 130 cm in length, with males growing larger than females. Large males reach 140-160cm in some populations. The maximum reported length is 180 cm.

The body has an exceedingly rough appearance as the normal dorsal scale keels are accentuated into protuberances or tuberculations. This is most apparent on the scale rows to either side of the body with a decreasing intensity in the lower rows. The vertebral scales are about as prominently keeled as the fourth row down on the flanks (with the vertebral scales as the first row).

Geographic range

Found from 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 southwestern Michoacán

Michoacán

Michoacán officially Estado Libre y Soberano de Michoacán de Ocampo is one of the 31 states which, with the Federal District, comprise the 32 Federal Entities of Mexico. It is divided in 113 municipalities and its capital city is Morelia...

 on the Pacific coast, and Veracruz

Veracruz

Veracruz, formally Veracruz de Ignacio de la Llave officially Estado Libre y Soberano de Veracruz de Ignacio de la Llave , is one of the 31 states that, along with the Federal District, comprise the 32 federative entities of Mexico. It is divided in 212 municipalities and its capital city is...

 and the Yucatan Peninsula

Yucatán Peninsula

The Yucatán Peninsula, in southeastern Mexico, separates the Caribbean Sea from the Gulf of Mexico, with the northern coastline on the Yucatán Channel...

 on the Atlantic coast, south through Belize

Belize

Belize is a constitutional monarchy and the northernmost country in Central America. Belize has a diverse society, comprising many cultures and languages. Even though Kriol and Spanish are spoken among the population, Belize is the only country in Central America where English is the official...

, Guatemala

Guatemala

Guatemala is a country in Central America bordered by Mexico to the north and west, the Pacific Ocean to the southwest, Belize to the northeast, the Caribbean to the east, and Honduras and El Salvador to the southeast...

, El Salvador

El Salvador

El Salvador or simply Salvador is the smallest and the most densely populated country in Central America. The country's capital city and largest city is San Salvador; Santa Ana and San Miguel are also important cultural and commercial centers in the country and in all of Central America...

, Honduras

Honduras

Honduras is a republic in Central America. It was previously known as Spanish Honduras to differentiate it from British Honduras, which became the modern-day state of Belize...

 and Nicaragua

Nicaragua

Nicaragua is the largest country in the Central American American isthmus, bordered by Honduras to the north and Costa Rica to the south. The country is situated between 11 and 14 degrees north of the Equator in the Northern Hemisphere, which places it entirely within the tropics. The Pacific Ocean...

 to west-central Costa Rica

Costa Rica

Costa Rica , officially the Republic of Costa Rica is a multilingual, multiethnic and multicultural country in Central America, bordered by Nicaragua to the north, Panama to the southeast, the Pacific Ocean to the west and the Caribbean Sea to the east....

. It is absent from Panama

Panama

Panama , officially the Republic of Panama , is the southernmost country of Central America. Situated on the isthmus connecting North and South America, it is bordered by Costa Rica to the northwest, Colombia to the southeast, the Caribbean Sea to the north and the Pacific Ocean to the south. The...

, but apparently does occur on the Atlantic side of Colombia

Colombia

Colombia, officially the Republic of Colombia , is a unitary constitutional republic comprising thirty-two departments. The country is located in northwestern South America, bordered to the east by Venezuela and Brazil; to the south by Ecuador and Peru; to the north by the Caribbean Sea; to the...

. The type locality given is "Ceylan," which is incorrect.

Habitat

Usually found in regions that are semiarid, including tropical forests that are dry or very dry, thorn woodland and arid scrub forest. It also occurs in mesic forests with relatively dry open areas.

Cultural Significance

To the Mayans and their living descendants, the Yucatan subspecies (C. s. tzabcan) was greatly revered. The word tzabcan means rattlesnake in Mayan. It is unknown what the rattlesnake actually symbolizes, but many temples have had rattlesnake shapes carved. Shamans also dry and roast snakes, grinding them into a powder used as medicine.

Venom

Bites from this species are similar to rattlesnake

Crotalus

Crotalus is a genus of venomous pit vipers found only in the Americas from southern Canada to northern Argentina. The name is derived from the Greek word krotalon, which means "rattle" or "castanet", and refers to the rattle on the end of the tail which makes this group so distinctive...

 bites in the United States

United States

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

. Local symptoms may be severe, with pain, massive swelling, blistering and necrosis that often lead to physicians performing fasciotomies

Fasciotomy

Fasciotomy or fasciectomy is a surgical procedure where the fascia is cut to relieve tension or pressure . Fasciotomy is a limb-saving procedure when used to treat acute compartment syndrome. It is also sometimes used to treat chronic compartment stress syndrome...

 and in some cases amputation

Amputation

Amputation is the removal of a body extremity by trauma, prolonged constriction, or surgery. As a surgical measure, it is used to control pain or a disease process in the affected limb, such as malignancy or gangrene. In some cases, it is carried out on individuals as a preventative surgery for...

s. Systemic effects involving hemostatic disturbances are rare, as are renal failure and neurotoxicity. Only venom from neonates contains crotoxin; a constituent typically found in C. durissus

Crotalus durissus

Crotalus durissus is a venomous pitviper species found in South America. The most widely distributed member of its genus, this species poses a serious medical problem in many parts of its range...

 venom that produces neurotoxic symptoms.

Subspecies

Subspecies	Taxon author	Common name	Geographic range
C. s. culminatus	Klauber Laurence Monroe Klauber Laurence M. Klauber , was an American herpetologist, and was considered to be the foremost authority on rattlesnakes... , 1952	Northwestern Neotropical 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...  in southwestern Michoacán Michoacán Michoacán officially Estado Libre y Soberano de Michoacán de Ocampo is one of the 31 states which, with the Federal District, comprise the 32 Federal Entities of Mexico. It is divided in 113 municipalities and its capital city is Morelia... , southern and western Morelos Morelos Morelos officially Estado Libre y Soberano de Morelos is one of the 31 states which, with the Federal District, comprise the 32 Federal Entities of Mexico. It is divided in 33 municipalities and its capital city is Cuernavaca.... , Guerrero Guerrero Guerrero officially Estado Libre y Soberano de Guerrero is one of the 31 states which, with the Federal District, comprise the 32 Federal Entities of Mexico. It is divided in 81 municipalities and its capital city is Chilpancingo....  and southwestern Oaxaca Oaxaca Oaxaca , , officially Estado Libre y Soberano de Oaxaca is one of the 31 states which, along with the Federal District, comprise the 32 federative entities of Mexico. It is divided into 571 municipalities; of which 418 are governed by the system of customs and traditions... . It probably also occurs in extreme western Puebla Puebla Puebla officially Estado Libre y Soberano de Puebla is one of the 31 states which, with the Federal District, comprise the 32 Federal Entities of Mexico. It is divided in 217 municipalities and its capital city is Puebla....  and possibly in the Mexican Federal District.
C. s. simus	Latreille Pierre André Latreille Pierre André Latreille was a French zoologist, specialising in arthropods. Having trained as a Roman Catholic priest before the French Revolution, Latreille was imprisoned, and only regained his freedom after recognising a rare species he found in the prison, Necrobia ruficollis...  In Sonnini & Latreille, 1801	Central American rattlesnake	Southeastern Mexico (central Veracruz Veracruz Veracruz, formally Veracruz de Ignacio de la Llave officially Estado Libre y Soberano de Veracruz de Ignacio de la Llave , is one of the 31 states that, along with the Federal District, comprise the 32 federative entities of Mexico. It is divided in 212 municipalities and its capital city is... , southeastern Oaxaca Oaxaca Oaxaca , , officially Estado Libre y Soberano de Oaxaca is one of the 31 states which, along with the Federal District, comprise the 32 federative entities of Mexico. It is divided into 571 municipalities; of which 418 are governed by the system of customs and traditions... , Tabasco Tabasco Tabasco officially Estado Libre y Soberano de Tabasco is one of the 31 states which, with the Federal District, comprise the 32 Federal Entities of Mexico. It is divided in 17 municipalities and its capital city is Villahermosa....  and Chiapas Chiapas Chiapas officially Estado Libre y Soberano de Chiapas is one of the 31 states that, with the Federal District, comprise the 32 Federal Entities of Mexico. It is divided in 118 municipalities and its capital city is Tuxtla Gutierrez. Other important cites in Chiapas include San Cristóbal de las... ), central and southern Guatemala Guatemala Guatemala is a country in Central America bordered by Mexico to the north and west, the Pacific Ocean to the southwest, Belize to the northeast, the Caribbean to the east, and Honduras and El Salvador to the southeast... , western and southern Honduras Honduras Honduras is a republic in Central America. It was previously known as Spanish Honduras to differentiate it from British Honduras, which became the modern-day state of Belize... , southern Belize Belize Belize is a constitutional monarchy and the northernmost country in Central America. Belize has a diverse society, comprising many cultures and languages. Even though Kriol and Spanish are spoken among the population, Belize is the only country in Central America where English is the official... , El Salvador El Salvador El Salvador or simply Salvador is the smallest and the most densely populated country in Central America. The country's capital city and largest city is San Salvador; Santa Ana and San Miguel are also important cultural and commercial centers in the country and in all of Central America... , southwestern Nicaragua Nicaragua Nicaragua is the largest country in the Central American American isthmus, bordered by Honduras to the north and Costa Rica to the south. The country is situated between 11 and 14 degrees north of the Equator in the Northern Hemisphere, which places it entirely within the tropics. The Pacific Ocean... , and northwestern and central Costa Rica Costa Rica Costa Rica , officially the Republic of Costa Rica is a multilingual, multiethnic and multicultural country in Central America, bordered by Nicaragua to the north, Panama to the southeast, the Pacific Ocean to the west and the Caribbean Sea to the east.... .
C. s. tzabcan	Klauber Laurence Monroe Klauber Laurence M. Klauber , was an American herpetologist, and was considered to be the foremost authority on rattlesnakes... , 1952	Yucatán Neotropical rattlesnake	Mexico (Yucatán Yucatán Yucatán officially Estado Libre y Soberano de Yucatán is one of the 31 states which, with the Federal District, comprise the 32 Federal Entities of Mexico. It is divided in 106 municipalities and its capital city is Mérida.... , Campeche Campeche Campeche is one of the 31 states which, with the Federal District, comprise the 32 Federal Entities of Mexico. Located in Southeast Mexico, it is bordered by the states of Yucatán to the north east, Quintana Roo to the east, and Tabasco to the south west... , Quintana Roo Quintana Roo Quintana Roo officially Estado Libre y Soberano de Quintana Roo is one of the 31 states which, with the Federal District, comprise the 32 Federal Entities of Mexico. It is divided in 10 municipalities and its capital city is Chetumal....  and eastern Tabasco Tabasco Tabasco officially Estado Libre y Soberano de Tabasco is one of the 31 states which, with the Federal District, comprise the 32 Federal Entities of Mexico. It is divided in 17 municipalities and its capital city is Villahermosa.... ), northern Guatemala Guatemala Guatemala is a country in Central America bordered by Mexico to the north and west, the Pacific Ocean to the southwest, Belize to the northeast, the Caribbean to the east, and Honduras and El Salvador to the southeast...  and northern Belize Belize Belize is a constitutional monarchy and the northernmost country in Central America. Belize has a diverse society, comprising many cultures and languages. Even though Kriol and Spanish are spoken among the population, Belize is the only country in Central America where English is the official... .

Taxonomy

Previously, until 2004, the description for this form was listed as the nominate subspecies for the tropical rattlesnake, C. durissus

Crotalus durissus

Crotalus durissus is a venomous pitviper species found in South America. The most widely distributed member of its genus, this species poses a serious medical problem in many parts of its range...

. Molecular genetic data suggest that the taxa culminatus and tzabcan should be considered as separate species from C. simus