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Home/Species/ Mohave Rattlesnake

Crotalus scutulatus

(Kennicott, 1861)

Mohave Rattlesnake

G5Secure Found in 18 roadless areas NatureServe Explorer →
G5SecureGlobal Rank
Least concernIUCN
LowThreat Impact
Identity
Unique IDELEMENT_GLOBAL.2.100052
Element CodeARADE02100
Record TypeSPECIES
ClassificationSpecies
Classification StatusStandard
Name CategoryVertebrate Animal
IUCNLeast concern
Endemicoccurs (regularly, as a native taxon) in multiple nations
KingdomAnimalia
PhylumCraniata
ClassReptilia
OrderSquamata
FamilyViperidae
GenusCrotalus
Other Common Names
Mojave rattlesnake (EN) Mojave Rattlesnake (EN)
Concept Reference
Pyron, R. A., F. T. Burbrink, and J. J. Wiens. 2013. A phylogeny and revised classification of Squamata, including 4161 species of lizards and snakes. BMC Evolutionary Biology 29:131.
Taxonomic Comments
The spelling of the word "Mojave" or "Mohave" has been a subject of debate. Lowe, in the preface to his Venomous Reptiles of Arizona (1986), argued for "Mohave" as did Campbell and Lamar (2004). According to linguistic experts on Native American languages, either spelling is correct, but using either the "j" or "h" is based on whether the word is used in a Spanish or English context. Given that this is an English names list, Crother (2017) use the "h" spelling (P. Munro, Linguistics, UCLA, pers. comm.). Jones (2016) argued that the spelling should be with "j" but the committee was not convinced and voted to continue to spell it as Mohave (Crother 2017).

The traditional view of rattlesnake taxonomy that recognizes the two monophyletic sister genera Crotalus and Sistrurus (e.g. Brattstrom 1964) has recently been challenged. Stille (1987) and McCranie (1988) presented data that suggested Sistrurus is not monophyletic and rendered Crotalus paraphyletic. Parkinson (1999) found Sistrurus monophyletic but its position rendered Crotalus paraphyletic. Knight et al. (1993) used mtDNA to defend the traditional generic taxonomy, but in order to do so ignored the most parsimonious tree. The genus Crotalus is monophyletic when including the Mexican C. ravus (Murphy et al. 2002), and is supported as such in most recent phylogenies, as well as being the sister taxon to a monophyletic Sistrurus (e.g., Pyron et al. 2013) (Crother 2017).

Two geographically distinct venom types are produced by populations in Arizona; biochemical evidence indicates that there is high gene flow between the populations producing the different venom types and that they are conspecific (Wilkinson et al. 1991). Venom characteristics indicate hybridization between C. scutulatus and C. viridis in New Mexico (Glenn and Straight 1990).
Conservation Status
Review Date2006-08-29
Change Date1996-10-31
Edition Date2006-08-29
Edition AuthorsHammerson, G.
Threat ImpactLow
Range Extent200,000-2,500,000 square km (about 80,000-1,000,000 square miles)
Number of Occurrences81 to >300
Range Extent Comments
The range extends from southern California, southern Nevada, and southwestern Utah south through Arizona (Lowe et al. 1986), southern New Mexico (Degenhardt et al. 1996), western Texas (Tennant 1984), and central Mexico to near the south end of the Mexican Plateau in Puebla and adjacent Veracruz (Stebbins 2003, Campbell and Lamar 2004). Elevational range extends from sea level to around 2,530 meters (8,300 feet) (Stebbins 2003); above 1,800 meters at the southern end of the range (Campbell and Lamar 2004).
Occurrences Comments
This species is represented by a large number of occurrences (subpopulations). On a range-wide scale, Campbell and Lamar (2004) mapped hundreds of collection sites.
Threat Impact Comments
No major threats are known.
Ecology & Habitat

Habitat

Habitat is mostly upland desert and lower mountain slopes, including barren desert, grassland, open woodland, and scrubland; in the United States, vegetation in most occupied areas includes creosotebush, palo verde, mesquite, or cacti (Ernst 1992, Ernst and Ernst 2003, Stebbins 2003, Campbell and Lamar 2004). This snake usually is not in broken rocky terrain or densely vegetated areas. In southeastern Arizona, it is more numerous in semidesert grassland than in desert scrub (Mendelson and Jennings 1992). In southern Arizona and adjacent Mexico, it is very common in prairie valleys between forested mountain ranges (Armstrong and Murphy 1979). In the southern part of the range in Mexico, it occurs in open high interior plains, mesquite-grassland, pine-oak, and lava beds with cactus, agave, and grasses (Armstrong and Murphy 1979). In spring, this snake commonly coils under a small tree or shrub in early morning (Armstrong and Murphy 1979). Refuges include animal burrows, spaces under or among rocks, or similar sites.

Reproduction

Young are born mainly July-August (often mid-August), sometimes in September. Litter size ranges up to 17 (Herp. Rev. 21:93), average around 8.
Terrestrial Habitats
Woodland - HardwoodWoodland - ConiferWoodland - MixedShrubland/chaparralGrassland/herbaceousDesert
Other Nations (1)
United StatesN5
ProvinceRankNative
NevadaS4Yes
UtahS2Yes
New MexicoS3Yes
TexasS4Yes
CaliforniaSNRYes
ArizonaS5Yes
Roadless Areas (18)
Arizona (11)
AreaForestAcres
Arnold MesaPrescott National Forest12,286
Black CanyonPrescott National Forest10,683
ChiricahuaCoronado National Forest76,876
GaliuroCoronado National Forest28,333
Grief HillPrescott National Forest12,535
Lower RinconCoronado National Forest3,278
Middle Dragoon RoadlessCoronado National Forest10,543
PinalenoCoronado National Forest130,920
Upper Dragoon RoadlessCoronado National Forest2,533
WhetstoneCoronado National Forest20,728
WinchesterCoronado National Forest13,459
California (5)
AreaForestAcres
Fish CanyonAngeles National Forest29,886
Granite PeakSan Bernardino National Forest450
Pleasant ViewAngeles National Forest26,395
ScodiesSequoia National Forest725
TuleAngeles National Forest9,861
Nevada (1)
AreaForestAcres
Lovell Summit SouthHumboldt-Toiyabe National Forest28,455
New Mexico (1)
AreaForestAcres
Peloncillo (NM)Coronado National Forest43,339
References (30)
  1. Armstrong, B. L., and J. B. Murphy. 1979. The natural history of Mexican rattlesnakes. Univ. Kansas Museum Natural History Special Publication. No. 5. vii + 88 pp.
  2. Behler, J. L., and F. W. King. 1979. The Audubon Society field guide to North American reptiles and amphibians. Alfred A. Knopf, New York. 719 pp.
  3. Brattstrom, B. H. 1964. Evolution of the pit vipers. Transactions of the San Diego Society of Natural History 13(11):185-268.
  4. Campbell, J. A., and E. D. Brodie, Jr., editors. 1992. Biology of the pit vipers. Selva, Tyler, Texas.
  5. Campbell, J. A., and W. W. Lamar. 1989. The venomous reptiles of Latin America. Comstock Publ. Associates, Division of Cornell Univ. Press, Ithaca, New York. xii + 425 pp.
  6. Campbell, J. A., and W. W. Lamar. 2004. The venomous reptiles of the Western Hemisphere. 2 volumes. Cornell University Press.
  7. Collins, J. T. 1990. Standard common and current scientific names for North American amphibians and reptiles. 3rd ed. Society for the Study of Amphibians and Reptiles. Herpetological Circular No. 19. 41 pp.
  8. Conant, R. and J. T. Collins. 1991. A field guide to reptiles and amphibians: eastern and central North America. Third edition. Houghton Mifflin Co., Boston, Massachusetts. 450 pp.
  9. Crother, B. I. (editor). 2012. Scientific and standard English names of amphibians and reptiles of North America north of Mexico, with comments regarding confidence in our understanding. 7th edition. SSAR Herpetological Circular 39:1-92.
  10. Crother, B. I. (editor). 2017. Scientific and standard English names of amphibians and reptiles of North America north of Mexico, with comments regarding confidence in our understanding. 8th edition. SSAR Herpetological Circular 43:1-104. [Updates in SSAR North American Species Names Database at: https://ssarherps.org/cndb]
  11. Degenhardt, W. G., C. W. Painter, and A. H. Price. 1996. Amphibians and reptiles of New Mexico. University of New Mexico Press, Albuquerque. xix + 431 pp.
  12. Ernst, C. H. 1992. Venomous reptiles of North America. Smithsonian Institution Press, Washington, D.C. ix + 236 pp.
  13. Glenn, J. L., and R. C. Straight. 1990. Venom characteristics as an indicator of hybridization between <i>Crotalus viridis viridis</i> and <i>Crotalus scutulatus</i> in New Mexico. Toxicon 28:857-862.
  14. Gloyd, H. 1940. The rattlesnakes. Chicago Academy Science, Special Publication No. 4.
  15. Jones, L.L.C. 2016. The spelling of Mojave vs Mohave as it applies to standard English names for reptiles and amphibians. Sonoran Herpetologist 29(4):65-71.
  16. Klauber, L. M. 1972. Rattlesnakes: their habits, life histories, and influence on mankind. Second edition. Two volumes. Univ. California Press, Berkeley.
  17. Knight, A., D. Styer, S. Pelikan, J. A. Campbell, L. D. Densmore III, and D. P. Mindell. 1993. Choosing among hypotheses of rattlesnake phylogeny: a best-fit rate test for DNA sequence data. Systematic Biology 42(3):356-367.
  18. Lowe, C. H., C. R. Schwalbe, and T. B. Johnson. 1986. The venomous reptiles of Arizona. Arizona Game and Fish Department. ix + 115 pp.
  19. McCranie, J. R. 1988. Description of the hemipenis of <i>Sistrurus ravus </i>(Serpentes: Viperidae). Herpetologica 44:123-126.
  20. Mendelson, J. R., III, and W. B. Jennings. 1992. Shifts in the relative abundance of snakes in a desert grassland. J. Herpetol. 26:38-45.
  21. Murphy, R. W., J. Fu, and A. Lathrop. 2002. Phylogeny of the rattlesnakes (<i>Crotalus </i>and <i>Sistrurus</i>) inferred from sequences of five mitochondrial DNA genes. Pages 69-92 in G. W. Schuett, M. Hoggren, M. E. Douglas, and H. W. Greene, editors. Biology of the Vipers. Eagle Mountain Publishing, Eagle Mountain, Utah.
  22. Parkinson, C. L. 1999. Molecular systematics and biogeographical history of pitvipers as determined by mitochondrial ribosomal DNA sequences. Copeia 1999:576-586.
  23. Price, A. H. 1982. Crotalus scutulatus. Cat. Am. Amph. Rep. 291.1-291.2.
  24. Pyron, R. A., F. T. Burbrink, and J. J. Wiens. 2013. A phylogeny and revised classification of Squamata, including 4161 species of lizards and snakes. BMC Evolutionary Biology 29:131.
  25. Stebbins, R. C. 1985a. A field guide to western reptiles and amphibians. Second edition. Houghton Mifflin Company, Boston, Massachusetts. xiv + 336 pp.
  26. Stebbins, R. C. 2003. A field guide to western reptiles and amphibians. Third edition. Houghton Mifflin Company, Boston.
  27. Stille, B. 1987. Dorsal scale microdermatoglyphics and rattlesnake (<i>Crotalus </i>and <i>Sistrurus</i>) phylogeny (Reptilia: Viperidae: Crotalinae). Herpetologica:98-104.
  28. Tennant, A. 1984. The Snakes of Texas. Texas Monthly Press, Austin, Texas. 561 pp.
  29. Werler, J. E., and J. R. Dixon. 2000. Texas snakes: identification, distribution, and natural history. University of Texas Press, Austin. xv + 437 pp.
  30. Wilkinson, J. A., et al. 1991. Distribution and genetic variation in venom A and B populations of the Mojave rattlesnake (<i>Crotalus scutulatus</i> <i>scutulatus</i>) in Arizona. Herpetologica 47:54-68.