View source for Crotalus ruber

{{Short description|Species of snake}}
{{Speciesbox
| name = Red diamond rattlesnake
| image = Crotalus ruber1.jpg
| status = NT
| status_system = IUCN3.1
| status_ref = <ref>''Crotalus ruber'' https://explorer.natureserve.org/Taxon/ELEMENT_GLOBAL.2.100051/Crotalus_ruber </ref>
| genus = Crotalus
| species = ruber
| authority = [[Edward Drinker Cope|Cope]], 1892
| range_map = Crotalus ruber distribution.png
| synonyms = {{collapsible list|bullets = true|title=<small>List</small>
| ''Caudisona atrox sonoraensis'' - Kennicott, 1861
| ''Crotalus adamanteus atrox'' - Cope, 1875
| ''Crotalus exsul'' - Garman, 1884
| ''Crotalus adamanteus ruber'' - Cope, 1892
| ''Crotalus ruber'' - Van Denburgh, 1896
| ''Crotalus atrox ruber'' - Stejneger, 1895
| ''Crotalus exsul'' - Grinnell & Camp, 1917
| ''Crotalus atrox elegans'' - Schmidt, 1922
| ''Crotalus exul ruber'' - Kallert, 1927
| ''Crotalus ruber ruber'' - Klauber, 1949
| ''Crotalus ruber elegans'' - Harris & Simmons, 1978
| ''Crotalus ruber monserratensis'' - Harris & Simmons, 1978
| ''Crotalus exsul exsul'' - Grismer, McGuire & Hollingsworth, 1994<ref name="McD99">McDiarmid RW, Campbell JA, Touré T. 1999. Snake Species of the World: A Taxonomic and Geographic Reference, vol. 1. Herpetologists' League. 511 pp. {{ISBN|1-893777-00-6}} (series). {{ISBN|1-893777-01-4}} (volume).</ref>
}}
}}

:'''''Common names:''' red diamond rattlesnake, red rattlesnake, red diamond snake,<ref name="W&W57">Wright AH, Wright AA. 1957. Handbook of Snakes. Comstock Publishing Associates. (7th printing, 1985). 1105 pp. {{ISBN|0-8014-0463-0}}.</ref> [[#Common names|more]]''

'''''Crotalus ruber''''' is a [[venomous snake|venomous]] [[Crotalinae|pit viper]] [[species]] found in southwestern [[California]] in the [[United States]] and [[Baja California]] in [[Mexico]]. Three [[subspecies]] are currently recognized, including the [[nominate subspecies]] described here.<ref name="ITIS">{{ITIS |id=174316 |taxon=Crotalus ruber |accessdate=7 February 2007}}</ref>

==Description==
[[File:Crotalus-ruber.jpg|thumb|left|''C. ruber'']] 
This moderately large species commonly exceeds {{convert|100|cm|in|abbr=on}} on the mainland. Large males may exceed {{convert|140|cm|in|abbr=on}}, although specimens of over {{convert|150|cm|in|abbr=on}} are quite rare. The largest specimen on record measured {{convert|162|cm|in|abbr=on}} (Klauber, 1937).<ref name="C&L04">Campbell JA, Lamar WW. 2004. The Venomous Reptiles of the Western Hemisphere. Comstock Publishing Associates, Ithaca and London. 870 pp. 1500 plates. {{ISBN|0-8014-4141-2}}.</ref>

''Crotalus ruber'' is very similar in pattern to ''C. atrox'', but it is distinguished by its reddish color, to which the [[Specific name (zoology)|specific name]], ''ruber'', refers. Also, the first lower labial scale on each side is transversely divided to form a pair of anterior chin shields.<ref>[[Karl Patterson Schmidt|Schmidt, K.P.]] and D.D. Davis. ''Field Book of Snakes of the United States and Canada''. G.P. Putnam's Sons. New York. 365 pp. ("Red Diamond Rattlesnake.&ndash;''Crotalus ruber'' Cope.", pp. 299-300 & Plate 32.)</ref>

The dorsal scales are usually arranged in 29 rows, but may vary from 25 to 31 rows. Ventrals range from 185 to 206.<ref>[[Hobart Muir Smith|Smith, H.M.]] and E.D. Brodie, Jr. 1982. ''Reptiles of North America: A Guide to Field Identification''. Golden Press. New York. 240 pp. ("RED DIAMOND RATTLESNAKE (''Crotalus ruber'')", pp. 204-205.)</ref>

Snakes found in coastal regions are longer on average than those found in desert regions.<ref>Eric A. Dugan and William K. Hayes (2012) Diet and Feeding Ecology of the Red Diamond Rattlesnake, Crotalus ruber (Serpentes: Viperidae). Herpetologica: June 2012, Vol. 68, No. 2, pp. 203-217.</ref>

==Common names==
Common names include: red diamond rattlesnake, red rattlesnake, red diamond snake, red diamond-backed rattlesnake, red rattler, and [[western diamond rattlesnake (disambiguation)|western diamond rattlesnake]].<ref name="W&W57"/> The form found on [[Cedros Island]], previously described as ''C. exsul'', was referred to as the Cedros Island diamond rattlesnake,<ref name="Kla97">Klauber LM. 1997. Rattlesnakes: Their Habitats, Life Histories, and Influence on Mankind. Second Edition. First published in 1956, 1972. University of California Press, Berkeley. {{ISBN|0-520-21056-5}}.</ref> or Cedros Island rattlesnake.<ref name="Dit33">Ditmars RL. 1933. Reptiles of the World. Revised Edition. The MacMillan Company. 329 pp. 89 plates.</ref>

==Geographic range==
Red diamond rattlesnakes are found in the United States in southwestern [[California]] and southward through the [[Baja California]] peninsula, although not in the desert east of the [[Sierra de Juárez]] in northeastern Baja California. It also inhabits a number of islands in the [[Gulf of California]], including [[Angel de la Guarda]], Pond, San Lorenzo del Sur, [[San Marcos, Baja California Sur|San Marcos]], Danzante, [[Monserrate]] and San José. Off the west coast of Baja California, it is found on [[Santa Margarita Island (Mexico)|Isla de Santa Margarita]], which is off [[Baja California Sur]], and (as ''C. ruber exsul'') on [[Isla de Cedros]].<ref name="McD99"/> Dwelling in brush covered hillsides, a favored habitat is the small caves and clefts of reddish sandstone mesas.<ref name=SC>{{cite book|last1=Campbell|first1=Sheldon|last2=Shaw|first2=Charles E.|title=Snakes of The American West|year=1974|publisher=[[Alfred A. Knopf]]|location=New York|isbn=978-0-394-48882-0}}</ref>
[[File:Red Diamond Rattlesnake, San Diego Zoo Safari Park, San Diego, CA, US imported from iNaturalist photo 21507732.jpg|thumb|Eating a [[cottontail rabbit]]]]

==Conservation status==
This species is classified as Least Concern on the [[IUCN Red List]] of Threatened Species (v3.1, 2001).<ref name="ICUN">{{Redlist species|no=64331|genus=Crotalus|species=ruber|date=13 September|year=2007}}</ref> Species are listed as such 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. The population trend was down when assessed in 2007.<ref name="ICUN-31">{{Redlist CC2001|date=13 September|year=2007}}</ref>

==Habitat==
''C. ruber'' inhabits the cooler coastal zone, over the mountains, and into the desert beyond. It prefers the dense [[chaparral]] country of the foothills, cactus patches, and boulders covered with brush, from sea level to 1,500&nbsp;m  in altitude.<ref name="B&K79">Behler JL, King FW. 1979. The Audubon Society Field Guide to North American Reptiles and Amphibians. New York: Alfred A. Knopf. 743 pp. LCCCN 79-2217. {{ISBN|0-394-50824-6}}.</ref>

==Diet==
This species preys on rabbits, ground squirrels, birds,<ref name="B&K79"/>  lizards, and other snakes.<ref name="W&W57"/><ref name="Wright and Wright 1957">Wright and Wright (1957)</ref>
Snakes from coastal populations consume prey of larger body mass than snakes from desert populations.<ref>Eric A. Dugan and William K. Hayes (2012) Diet and Feeding Ecology of the Red Diamond Rattlesnake, Crotalus ruber (Serpentes: Viperidae). Herpetologica: June 2012, Vol. 68, No. 2, pp. 203-217.</ref>

==Reproduction==
Mating occurs between February and April. ''C. ruber'' is known to be [[Ovoviviparity|ovovivparous]].<ref name=":0" /> Females give birth in August, to between three and 20 young. Neonates are 30 to 34&nbsp;cm in length.<ref name="B&K79"/>

==Venom==
[[File:Crotalus ruber male video.ogv|thumb|180px|''C. ruber'' shaking its rattle]]
As with all [[Rattlesnake|rattlesnakes]], it is [[Venom|venomous]].<ref name=":0">{{Cite web |title=Crotalus ruber |url=https://reptile-database.reptarium.cz/species?genus=Crotalus&species=ruber |access-date=2025-01-07 |website=The Reptile Database}}</ref> This species is of a mild disposition<ref name="Wright and Wright 1957"/> and has one of the least potent rattlesnake venoms. Nonetheless, a bite from this species is still a medical emergency and can be fatal without prompt antivenom treatment.

Brown (1973) lists an average venom yield of 364&nbsp;mg (dried) and {{LD50}} values of 4.0, 3.7&nbsp;mg/kg [[Intravenous therapy|IV]], 6.0, 7.0, 6.7&nbsp;mg/kg [[Peritoneum#Intraperitoneal|IP]] and 21.2&nbsp;mg/kg [[Subcutis|SC]] for toxicity.<ref name="Bro73">Brown JH. 1973. Toxicology and Pharmacology of Venoms from Poisonous Snakes. Springfield, Illinois: Charles C. Thomas. 184 pp. LCCCN 73-229. {{ISBN|0-398-02808-7}}.</ref>

However, Norris (2004) warned this species has a relatively large venom yield containing high levels of [[proteolytic enzyme]]s, especially in the adults. A publication he mentions by Rael ''et al.'' (1986) showed it contains at least three proteolytic hemorrhagins that degrade [[fibrinogen]] and cause [[myonecrosis]], but no [[Crotalus scutulatus#Venom|Mojave toxin]]. On the other hand, three specimens from Mexico studied by Glen ''et al.'' (1983) did have Mojave toxin and lacked hemorrhagic activity.<ref name="Nor-C&L04">Norris R. 2004. Venom Poisoning in North American Reptiles. ''In'' Campbell JA, Lamar WW. 2004. The Venomous Reptiles of the Western Hemisphere. Comstock Publishing Associates, Ithaca and London. 870 pp. 1500 plates. {{ISBN|0-8014-4141-2}}.</ref>

Bite symptoms include massive tissue swelling, pain, [[ecchymosis]], hemorrhagic blebs, and necrosis. Systemic symptoms may include nausea, vomiting, [[coagulopathy]], clinical bleeding and [[hemolysis]].<ref name="Nor-C&L04"/>

==Subspecies==
{|cellspacing=0 cellpadding=2 border=1 style="border-collapse: collapse;"
!bgcolor="#f0f0f0"|Subspecies<ref name="ITIS"/>
!bgcolor="#f0f0f0"|Taxon author<ref name="ITIS"/>
!bgcolor="#f0f0f0"|Common name
!bgcolor="#f0f0f0"|Geographic range<ref name="McD99"/>
|-
|''C. r. exsul''<ref name="C&L04"/>
|[[Samuel Garman|Garman]], 1884<ref name="C&L04"/>
|Cedros Island red diamond rattlesnake
|style="width:40%"|[[Mexico]], [[Cedros Island]]<ref name="Kla97"/>
|-
|''[[Crotalus ruber lucasensis|C. r. lucasensis]]''
|[[J. Van Denburgh|Van Denburgh]], 1920
|San Lucan red diamond rattlesnake
|Mexico, Cape region of lower [[Baja California]]
|-
|''C. r. ruber''
|[[Edward Drinker Cope|Cope]], 1892
|Red diamond rattlesnake
|The United States in southwestern California, and Mexico in Baja California, except for the Cape region of lower Baja California
|-
|}

''C. r. exsul'' is thought to have separated from the mainland sister subspecies of ''C. ruber'' 210 thousand years ago.<ref>{{Cite journal |last1=Douglas |first1=Michael E. |last2=Douglas |first2=Marlis R. |last3=Schuett |first3=Gordon W. |last4=Porras |first4=Louis W. |date=2006 |title=Evolution of rattlesnakes (Viperidae; ''Crotalus'') in the warm deserts of western North America shaped by Neogene vicariance and Quaternary climate change |url=https://www.researchgate.net/publication/6823290 |journal=Molecular Ecology |language=en |volume=15 |issue=11 |pages=3353–3374 |doi=10.1111/j.1365-294X.2006.03007.x |pmid=16968275 |bibcode=2006MolEc..15.3353D |issn=1365-294X}}</ref>

==Taxonomy==
Not enough genetic and morphological diversity exists between ''C. exsul'' from [[Cedros Island]] and ''C. ruber'' from the mainland to warrant the recognition of both species.<ref>Murphy ''et al.'' (1995)</ref> Since ''C. exsul'' Garman (1884) has priority over ''C. ruber'' Cope (1892), they suggested the island population be referred to as ''C. e. exsul'' and those from the mainland as ''C. e. ruber''. In response, Smith ''et al.'' (1998) petitioned the [[International Commission on Zoological Nomenclature|ICZN]] to validate ''ruber'' over ''exsul'' in the interest of nomenclatural stability. In 2000, the ICZN published Opinion 1960 in which they ruled ''C. ruber'' should have precedence over ''C. exsul''.<ref name="C&L04"/>

Hence, '''''Crotalus ruber exsul''''', also known as the '''Cedros Island Rattlesnake''', and native to [[Mexico]] is a [[subspecies]] of ''C. ruber''.<ref>{{cite journal| title=Phylogenetic relationships and origin of the rattlesnakes of the Gulf of California islands (Viperidae: Crotalinae: ''Crotalus'')| journal=Herpetological Journal| date=2019| volume=29| issue=3| pages=162–172| last1=Ruiz-Sanchez| first1=Eduardo| last2=Arnaud| first2=Gustavo| last3=Cruz-Andrés| first3=Oscar Roberto| last4=Garcia-De León| first4=Francisco Javier| doi=10.33256/hj29.3.162172| doi-access=free}}</ref>

==References==
{{Reflist}}

==Further reading==
{{Refbegin}}
* Cope ED. 1892. A critical review of the characters and variations of the snakes of North America. Proceedings of the U.S. National Museum 14(882): 589-694.
* Garman S. 1884. The reptiles and batrachians of North America. Memoires of the Museum of Comparative Zoology 8(3): 1-185.
* Murphy RW, Kovac V, Haddrath O, Oliver GS, Fishbein A. 1995. MtDNA gene sequence, allozyme, and morphological uniformity among red diamond rattlesnakes, ''Crotalus ruber'' and ''Crotalus exsul''. Canadian Journal of Zoology 73(2): 270-281.
* Smith HM, Brown LE, Chiszar D, Grismer LL, Allen GS, Fishbein A, Hollingsworth BD, McGuire JA, Wallach V, Strimple P, Liner EA. 1998. ''Crotalus ruber'' Cope, 1892 (Reptilia, Serpentes): proposed precedence of the specific name over that of ''Crotalus exsul'' Garman, 1884. Bulletin of Zoological Nomenclature 55(4): 229-232.
{{Refend}}

==External links==
{{Commons category|Crotalus ruber}}
* {{NRDB species|genus=Crotalus|species=ruber|date=12 December|year=2007}}
* [http://www.sdnhm.org/fieldguide/herps/crot-exs.html ''Crotalus exsul'' (=''Crotalus ruber'') Red Diamond Rattlesnake] at [http://www.sdnhm.org/ San Diego Museum of Natural History]. Accessed 7 February 2007.
* [https://www.youtube.com/watch?v=9XNdwKfkGzQ ''Crotalus exsul'' (=''Crotalus ruber'') Red Diamond Rattlesnake] Field Observation at Laguna Beach, CA, Water Tank Road. Accessed 26 March 2022.

{{Taxonbar|from=Q2033803}}

[[Category:Crotalus|ruber]]
[[Category:Reptiles of Mexico]]
[[Category:Reptiles of the United States]]
[[Category:Fauna of California]]
[[Category:Natural history of Baja California]]
[[Category:Natural history of Baja California Sur]]
[[Category:Fauna of the California chaparral and woodlands]]
[[Category:Fauna of the Colorado Desert]]
[[Category:Fauna of the Mojave Desert]]
[[Category:Fauna of Gulf of California islands]]
[[Category:Cedros Island]]
[[Category:Natural history of San Diego County, California]]
[[Category:Reptiles described in 1892]]
[[Category:Taxa named by Edward Drinker Cope]]