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Home/Species/ Trans-Pecos Ratsnake

Bogertophis subocularis

(Brown, 1901)

Trans-Pecos Ratsnake

G4Apparently Secure Found in 1 roadless area NatureServe Explorer →
G4Apparently SecureGlobal Rank
Least concernIUCN
UnknownThreat Impact
Identity
Unique IDELEMENT_GLOBAL.2.102636
Element CodeARADB46020
Record TypeSPECIES
ClassificationSpecies
Classification StatusStandard
Name CategoryVertebrate Animal
IUCNLeast concern
Endemicoccurs (regularly, as a native taxon) in multiple nations
KingdomAnimalia
PhylumCraniata
ClassReptilia
OrderSquamata
FamilyColubridae
GenusBogertophis
Concept Reference
Dowling, H. G., and R. M. Price. 1988. A proposed new genus for Elaphe subocularis and Elaphe rosaliae. The Snake 20:52-63.
Taxonomic Comments
This species was removed from the genus Elaphe and placed (with E. rosaliae) in the new genus Bogertophis by Dowling and Price (1988) (based on immunological comparisons). This was supported by mtDNA data (Utiger et al. 2002). Bogertophis is evolutionarily closer to Pituophis than to North American Elaphe, according to Dowling and Price (1988) and Price (1990). Burbrink and Lawson (2006) found that Bogertophis is part of the monophyletic New World Lampropeltini and not closely related to the Old World Elaphe. Also see Pyron and Burbrink (2009).
Conservation Status
Rank Method Rank calculation - Biotics v2
Review Date2025-09-28
Change Date2025-09-28
Edition Date2025-09-28
Edition AuthorsHammerson, G. (2005); rev. R. L. Gundy (2025)
Threat ImpactUnknown
Range Extent200,000-2,500,000 square km (about 80,000-1,000,000 square miles)
Number of Occurrences81 - 300
Rank Reasons
This species has a broad range in the southwestern U.S. and northern México. Threats are not well understood, though road mortality likely causes localized declines. Historically, collection for the pet trade also caused localized declines in the latter half of the 20th century.
Range Extent Comments
This species occurs in the southwestern United States and northern México. The range extends from southern New Mexico and southwestern Texas south through Chihuahua and Coahuila to Durango and Nuevo León, México (Price 1990, Lemos Espinal and Smith 2016, Lemos Espinal et al. 2016, Lemos Espinal et al. 2017, Painter et al. 2017, Lemos Espinal et al. 2018). Elevation range is 450-1,600 meters (1,475-5,250 feet) (Ernst and Ernst 2003). Using Global Biodiversity Information Facility (GBIF) (2025) records, range extent is estimated to be 501,193 km² (RARECAT 2025).
Occurrences Comments
This species is represented by at least several dozen (probably more than 100) occurrences or subpopulations. Doubtless many occurrences have not been documented because of difficult access to the habitat. Worthington (1980) mapped about 66 collection sites rangewide, including 16 in México. The relatively small number in México presumably reflects lesser collecting effort there relative to areas in the United States. Werler and Dixon (2000) mapped well over 100 collection sites in Texas, many clearly along roads through suitable habitat. Degenhardt et al. (1996) mapped 15 collection sites in New Mexico (about twice as many as mapped in New Mexico by Worthington).
Threat Impact Comments
Increasing road construction means this species is increasingly likely to face significant amounts of mortality from vehicle strikes (Lazcano et al. 2017).

Collection of gravid females for the pet trade along roads in Trans-Pecos Texas led to a substantial historical decline in roadside populations, but populations in undeveloped areas are probably little affected if at all (Price 1990). Due to readily available captive bred specimens in the pet trade, this threat is now likely very minimal (Prestridge 2009).
Ecology & Habitat

Habitat

Habitat encompasses dry, rocky terrain, including basins and valleys with mesquite, desert slopes with creosotebush, sotol, lechuguilla, agave, yucca, ocotillo, or acacia, and montane oak-juniper woodland (Werler and Dixon 2000). The type of rock may be granitic, limestone, or lava (Degenhardt et al. 1996). This snakes spend daylight hours in crevices or other underground retreats.

Reproduction

Lays clutch of 3-11 eggs in summer. Eggs hatch in about 9-15 weeks. Sexually mature in 2-3 years in captivity (Tennant 1984).
Terrestrial Habitats
Woodland - ConiferWoodland - MixedShrubland/chaparralGrassland/herbaceousDesertBare rock/talus/scree
Other Nations (1)
United StatesN4
ProvinceRankNative
New MexicoS3Yes
TexasS4Yes
Threat Assessments
ThreatScopeSeverityTiming
4 - Transportation & service corridorsRestricted (11-30%)UnknownHigh (continuing)
4.1 - Roads & railroadsRestricted (11-30%)UnknownHigh (continuing)
5 - Biological resource useRestricted (11-30%)Negligible or <1% pop. declineHigh (continuing)
5.1 - Hunting & collecting terrestrial animalsRestricted (11-30%)Negligible or <1% pop. declineHigh (continuing)
5.1.1 - Intentional use (species being assessed is the target)Restricted (11-30%)Negligible or <1% pop. declineHigh (continuing)

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Roadless Areas (1)
New Mexico (1)
AreaForestAcres
Last Chance CanyonLincoln National Forest8,934
References (29)
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  2. Burbrink, F. T., and R. Lawson. 2007. How and when did Old World rat snakes disperse into the New World? Molecular Phylogenetics and Evolution 43:173-189.
  3. 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.
  4. Conant, R. 1975. A Field Guide to Reptiles and Amphibians of Eastern and Central North America. Second Edition. Houghton Mifflin Company, Boston, Massachusetts. xvii + 429 pp.
  5. Crother, B. I. (editor). 2008. Scientific and standard English names of amphibians and reptiles of North America north of Mexico, with comments regarding confidence in our understanding. Sixth edition. Society for the Study of Amphibians and Reptiles Herpetological Circular 37:1-84. Online with updates at: http://www.ssarherps.org/pages/comm_names/Index.php
  6. 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.
  7. 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]
  8. 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.
  9. Dowling, H. G., and R. M. Price. 1988. A proposed new genus for <i>Elaphe subocularis</i> and <i>Elaphe rosaliae</i>. The Snake 20:52-63.
  10. Ernst, C. H., and E. M. Ernst. 2003. Snakes of the United States and Canada. Smithsonian Books, Washington, D.C.
  11. Lazcano, D., D. B. Esquivel Arévalo, A. I. Heredia Villarreal, J. A. García Salas, B. Navarro Velázquez, and M. Nevárez-de los Reyes. 2017. Notes on Mexican Herpetofauna 31: Are roads in Nuevo León, Mexico, taking their toll on snake populations? (Part II). Bulletin of the Chicago Herpetological Society 52(11): 185-194.
  12. Lemos-Espinal, J. A., and G. R. Smith. 2016. Amphibians and reptiles of the state of Coahuila, Mexico, with comparison with adjoining states. ZooKeys 593: 117–137. doi: 10.3897/zookeys.594.8289
  13. Lemos-Espinal, J. A., G. R. Smith, and A. Cruz. 2016. Amphibians and reptiles of the state of Nuevo León, Mexico. ZooKeys 594: 123–141. doi: 10.3897/zookeys.594.8289
  14. Lemos-Espinal, J. A., G. R. Smith, G. A. Woolrich-Piña, and A. Cruz. 2017. Amphibians and reptiles of Chihuahua, Mexico, with comparisons with adjoining states. ZooKeys 658: 105-130.
  15. Lemos-Espinal, J. A., G. R. Smith, H. Gadsden-Esparza, R. Valdez-Lares, and G. A. Woolrich-Piña. 2018. Amphibians and reptiles of the state of Durango, Mexico, with comparisons with adjoining states. ZooKeys 748: 65–87. doi: 10.3897/zookeys.748.22768
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  18. <p>NatureServe's Rapid Analysis of Rarity and Endangerment Conservation Assessment Tool (RARECAT). 2025. Version: 2.1.1 (released April 04, 2025).</p>
  19. Prestridge, H. L. 2009. Amphibian and reptile trade in Texas: current status and trends. M.S. thesis. Texas A&M University, College Station, TX. 172 pp.
  20. Price, R. M. 1990. <i>Bogertophis subocularis</i>. Catalogue of American Amphibians and Reptiles 497.1-497.2.
  21. Pyron, R. A., and F. T. Burbrink. 2009. Neogene diversification and taxonomic stability in the snake tribe Lampropeltini (Serpentes: Colubridae). Molecular Phylogenetics and Evolution 52:524-529.
  22. Smith, L. L. and C. K. Dodd, Jr. 2003. Wildlife mortality on U.S. Highway 441 across Paynes Prairie, Alachua County, Florida. Florida Scientist 66(2):128-140.
  23. Stebbins, R. C. 1985a. A field guide to western reptiles and amphibians. Second edition. Houghton Mifflin Company, Boston, Massachusetts. xiv + 336 pp.
  24. Stebbins, R. C. 2003. A field guide to western reptiles and amphibians. Third edition. Houghton Mifflin Company, Boston.
  25. Tennant, A. 1984. The Snakes of Texas. Texas Monthly Press, Austin, Texas. 561 pp.
  26. Tennant, A. 1998. A field guide to Texas snakes. Second edition. Gulf Publishing Company, Houston, Texas.
  27. Utiger, U., N. Helfenberger, B. SchC. Schmidt, M. Ruf, and V. Ziswiler. 2002. Molecular systematics and phylogeny of Old and New World ratsnakes, <i>Elaphe</i> auct., and related genera (Reptilia, Squamata, Colubridae). Russian Journal of Herpetology 9(2):105-124.
  28. Werler, J. E., and J. R. Dixon. 2000. Texas snakes: identification, distribution, and natural history. University of Texas Press, Austin. xv + 437 pp.
  29. Worthington, R. D. 1980. Elaphe subocularis. Cat. Am. Amph. Rep. 268.1-268.2.