Crotalus enyo
Encyclopedia
- Common names: Baja California rattlesnake, Lower California rattlesnake.
Crotalus enyo 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...
native to the coast and islands of northwestern 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...
. Three 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
The maximum reported length of this species is 89.8 cm (Klauber, 1972). It is sexually dimorphicSexual dimorphism
Sexual dimorphism is a phenotypic difference between males and females of the same species. Examples of such differences include differences in morphology, ornamentation, and behavior.-Examples:-Ornamentation / coloration:...
, with the males typically being larger than the females. The head is remarkably small and narrow, while the eyes are proportionately large.
Geographic range
Found in western MexicoMexico
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 the north it is found in the Baja California Peninsula
Baja California Peninsula
The Baja California peninsula , is a peninsula in northwestern Mexico. Its land mass separates the Pacific Ocean from the Gulf of California. The Peninsula extends from Mexicali, Baja California in the north to Cabo San Lucas, Baja California Sur in the south.The total area of the Baja California...
from around Río San Telmo on the west coast and from opposite Isla Angel de la Guarda
Isla Ángel de la Guarda
Isla Ángel de la Guarda, also called Archangel Island, and called Xazl Iimt east of Bahía de los Ángeles, and separated from the Baja California Peninsula by the Canal de Ballenas . It is the second largest of the eleven Midriff Islands or Islas Grandes. It is part of the state of Baja California,...
on the gulf coast, south to Cabo San Lucas
Cabo San Lucas
Cabo San Lucas , commonly called Cabo, is a city at the southern tip of the Baja California peninsula, in the municipality of Los Cabos in the Mexican state of Baja California Sur. As of the 2010 census, the population was 68,463 people...
. Also found on the following islands in the Gulf of California
Gulf of California
The Gulf of California is a body of water that separates the Baja California Peninsula from the Mexican mainland...
: San Marcos, Carmen, San José, San Francisco, Partida del Sur, Espírita Santo and Cerralvo. Off the pacific coast it is also found on the island of San Margarita. The type locality is "Cape San Lucas, Baja California Sur
Baja California Sur
Baja California Sur , is one of the 31 states which, with the Federal District, comprise the 32 Federal Entities of Mexico. Before becoming a state on October 8, 1974, the area was known as the South Territory of Baja California. It has an area of , or 3.57% of the land mass of Mexico and comprises...
."
Habitat
Prefers desert, but in the northwestern part of its range it can be found in chaparralChaparral
Chaparral is a shrubland or heathland plant community found primarily in the U.S. state of California and in the northern portion of the Baja California peninsula, Mexico...
country, while in the cape region (Sierra de San Lázaro) it occurs in pine-oak and tropical deciduous forest. It can be found in rocky areas with arid thronscrub and cacti, but sometimes also in sand dunes. Often attracted to human habitation where it has been found in piles of refuse.
Conservation status
This species is classified as Least Concern (LC) on the IUCNWorld 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: 2007.
Feeding
Snakes of this species, regardless of their size, are known to eat small rodents, lizards, and centipedes. This is in contrast to many other rattlesnake species that prey on lizards almost exclusively as juveniles, switching to mammals as adults. With C. enyo, small snakes eat lizards more often than do large ones, and large snakes eat mammals more often than do small ones. Adults also prey on large centipedes of the genus ScolopendraScolopendra
Scolopendra is a genus of centipedes of the family Scolopendridae.-Description:In temperate climates, only relatively small species occur, but species from the tropics may exceed .-Ecology and venom:...
.
Reproduction
Captive specimens have produced litters of 2-7 young. New born specimens with lengths of between 20.6 and 22.2 cm have been mentioned. Grismer (2002) reported finding neonates in the wild between late July and mid October, which would indicate that the species mates in the spring and gives birth in the summer or early fall.Subspecies
| Subspecies | Taxon author | Common name | Geographic range |
|---|---|---|---|
| C. e. cerralvensis | Cliff, 1954 | Cerralvo Island rattlesnake | Isla Cerralvo in the Gulf of California Gulf of California The Gulf of California is a body of water that separates the Baja California Peninsula from the Mexican mainland... . |
| C. e. enyo | (Cope Edward Drinker Cope Edward Drinker Cope was an American paleontologist and comparative anatomist, as well as a noted herpetologist and ichthyologist. Born to a wealthy Quaker family, Cope distinguished himself as a child prodigy interested in science; he published his first scientific paper at the age of nineteen... , 1861) |
Lower California rattlesnake | Baja California Baja California Baja California officially Estado Libre y Soberano de Baja California is one of the 31 states which, with the Federal District, comprise the 32 Federal Entities of Mexico. It is both the northernmost and westernmost state of Mexico. Before becoming a state in 1953, the area was known as the North... , Mexico, from about El Rosario southward down the peninsula. |
| C. e. furvus | Lowe & Norris, 1954 | Rosario rattlesnake | Baja California, Mexico, from about Río San Telmo south to around El Rosario. |
Taxonomy
All three of the current subspecies were recognized by Beaman and Grismer (1994) in their review, but indicated that C. e. furvus should not be considered a separate subspecies and that C. e. cerralvensis would best be considered a full species.External links
- Image of neonate C. e. furvus feeding at Ratelslangen.eu. Accessed 9 February 2007.
- Longevity record for C. enyo at Max Planck Institute for Demographic Research. Accessed 9 February 2007.
- Image of C. enyo at Cape Snakes. Accessed 9 February 2007.
- Closeup image of C. enyo at Ratelslangen.nl. Accessed 9 February 2007.
