:''Common names: Tortuga Island diamond rattlesnake,Campbell JA, Lamar WW. 2004. The Venomous Reptiles of the Western Hemisphere. Comstock Publishing Associates, Ithaca and London. 870 pp. 1500 plates. . Klauber LM. 1956. ''Rattlesnakes: Their Habitats, Life Histories, and Influence on Mankind''. Second Edition, 1997. irst published in 1956, 1972.University of California Press, Berkeley. . Tortuga Island rattlesnake.''Crotalus tortugensis''
a

Accessed 23 March 2007.'' ''Crotalus atrox tortugensis'' is a

venomous Venom or zootoxin is a type of toxin produced by an animal that is actively delivered through a wound by means of a bite, sting, or similar action. The toxin is delivered through a specially evolved ''venom apparatus'', such as fangs or a sti ...

pit viper The Crotalinae, commonly known as pit vipers,Mehrtens JM (1987). ''Living Snakes of the World in Color''. New York: Sterling Publishers. 480 pp. . or pit adders, are a subfamily (biology), subfamily of Viperidae, vipers found in Asia and the ...

subspecies In Taxonomy (biology), biological classification, subspecies (: subspecies) is a rank below species, used for populations that live in different areas and vary in size, shape, or other physical characteristics (Morphology (biology), morpholog ...

found only on Tortuga Island in the

Gulf of California The Gulf of California (), also known as the Sea of Cortés (''Mar de Cortés'') or Sea of Cortez, or less commonly as the Vermilion Sea (''Mar Vermejo''), is a marginal sea of the Pacific Ocean that separates the Baja California peninsula from ...

Description

This

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

is smaller than its close relative, '' C. atrox atrox'', with large males not growing too much more than in length. The largest specimen on record is ( Klauber, 1972). Compared to ''C. atrox atrox'', the head is shorter relative to the length of the body—a trait considered to be an indication of dwarfing, which is common in island populations. The color pattern consists of a gray to gray-brown ground color, occasionally with a slight purplish or pinkish hue, overlaid dorsally with a series of 32–41 dark brown to purplish-brown blotches running down the length of the body. The blotches are hexagonal or diamond-shaped, marked with black spots, and bordered with irregular black mottling.

Geographic range

Found only on Tortuga Island,

Baja California Sur Baja California Sur, officially the Free and Sovereign State of Baja California Sur, is a state in Mexico. It is the 31st and last state to be admitted, in 1974. It is also the second least populated Mexican state and the ninth-largest state by ...

, in the

Mexico Mexico, officially the United Mexican States, is a country in North America. It is the northernmost country in Latin America, and borders the United States to the north, and Guatemala and Belize to the southeast; while having maritime boundar ...

. Its type locality is "Tortuga Island".

Habitat

It lives in barren, rocky, desert terrain, sparsely covered with brush and cacti.

Conservation status

This subspecies is classified as "

Least Concern A least-concern species is a species that has been evaluated and categorized by the International Union for Conservation of Nature (IUCN) as not being a focus of wildlife conservation because the specific species is still plentiful in the wil ...

" on the

IUCN Red List The International Union for Conservation of Nature (IUCN) Red List of Threatened Species, also known as the IUCN Red List or Red Data Book, founded in 1964, is an inventory of the global conservation status and extinction risk of biological ...

of Threatened Species. The population trend was stable when assessed in 2007. Species are listed as "Least Concern" due to their wide distribution, presumed large population, or because they are unlikely to be declining fast enough to qualify for listing in a more threatened category. However, this

is threatened due to its limited range, though it is common on the island. ''Crotalus tortugensis''
a
San Diego Natural History Museum
Accessed 23 April 2007.

Behavior

Although Van Denburgh reported they would rattle vigorously when approached, they have been described as being less excitable than '' C. atrox atrox'', their mainland relative.

Feeding

Its diet apparently consists of mice. Several specimens from the island are reported to have contained mammal hair, and a white-footed mouse, ''Peromyscus dickeyi'', is common on the island.

Venom

Klauber (1956) gives an average venom yield of 56 mg for this species. For comparison, the same study yielded an average of 277 mg for ''C. atrox atrox''.

Taxonomy

Though most recent authors consider this taxon to be distinct, it may actually be

conspecific Biological specificity is the tendency of a characteristic such as a behavior or a biochemical variation to occur in a particular species. Biochemist Linus Pauling stated that "Biological specificity is the set of characteristics of living organism ...

with ''C. atrox''.

References

External links

*
''Crotalus tortugensis'', incl. brief info and picture
a
San Diego Natural History Museum
Accessed 23 April 2007. {{Taxonbar, from=Q2445131 atrox tortugensis Endemic reptiles of Mexico Endemic fauna of the Baja California Peninsula Fauna of Gulf of California islands Reptiles described in 1921 Taxa named by Joseph Richard Slevin