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Crotalus catalinensis
– Critically Endangered
Taxonomy
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Kingdom:
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ANIMALIA
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Phylum:
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CHORDATA
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Class:
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REPTILIA
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Order:
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SQUAMATA
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Family:
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VIPERIDAE
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Scientific Name:
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Crotalus catalinensis
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Species Authority:
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Cliff, 1954
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Common Name/s:
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SANTA CATALINA ISLAND RATTLESNAKE (Eng)
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Assessment Information
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Red List Category & Criteria:
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CR B1ab(v) ver 3.1 (2001)
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Year Assessed:
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2007
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Assessor/s:
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Avila Villegas, H., Frost, D.R. & Arnaud, G.
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Evaluator/s:
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Cox, N., Chanson, J.S. & Stuart, S.N. (Global Reptile Assessment Coordinating Team)
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Justification:
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Listed as Critically Endangered because it is known only from one location: Santa Catalina Island in the Gulf of California, Mexico, where it faces a number of threats. The threats include: a highly restricted range, the recent past presence of feral cats on the island, persecution for illegal trade, occasional killing by visitors to the island when they encounter the species, and land pollution left by visitors. Its vulnerability is increased by the fact that 70% of its diet is composed of the only rodent species on the island, hence any threat to the prey would have a direct impact on this species.
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Geographic Range
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Range Description:
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this species is endemic to Isla Santa Catalina, a 40 km² island in the Gulf of California, off the coast of Loreto, in Mexico (Campbell and Lamar, 1989).
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Range Map:
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 (click for detailed map)
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Countries:
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Native:
Mexico
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Population
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Population:
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It was formerly a common species, but has probably declined, principally due to over-collecting. Abundance data gathered between 2003 and 2004 fluctuated between 0.23 (one snake every four person-hours) in June to 2.11 (two snakes per person-hour) in August (H. Avila-Villegas, pers. comm.).
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Population Trend:
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Habitat and Ecology
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Habitat and Ecology:
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The island topography is composed of rocky hillsides separated by wide and narrow sandy arroyos bearing the typical Sonora Desert vegetation. This species occurs mainly in heavily-vegetated arroyos (dry creeks), but can also be found on rocky and scrubby hillsides, beneath roots and rocks or even in open areas of sandy soils. It is mainly nocturnal and can be easily found and caught. Most of its diet (70%) is composed of the endemic Catalina Deermouse Peromyscus slevini, the only ground mammal species on the island.
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System:
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Terrestrial
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Threats
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Threats:
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The main threat to this species is the loss of individuals by killing and illegal collection. "Pit fall" traps have been found on the island, and some fishermen have observed persons collecting reptiles in bags. Others have taken these people to the island to collect the species (what they get paid equals their profits in a week of hard work fishing). Santa Catalina Island is home to 10 reptile species, of which seven are endemic (Grismer, 2002). Insular endemic species are the most wanted in the illegal trade market, hence, are the more threatened (Mellink 1995). Its passive behaviour makes it easy to catch or kill. Population declines of its main prey, P. slevini is also an important threat. A population of feral cats invaded the island, Grismer (2002) observed several remains of C. catalinensis in the scants. These cats were eradicated in 2002 (J. Donlan pers. comm. to H. Avila-Villegas).
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Conservation Actions
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Conservation Actions:
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It is necessary to implement a program to control the population of feral cats inhabiting the island since at least three species of reptiles are predated by the cats.
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