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Tantilla planiceps

(Blainville, 1835)

Western Black-headed Snake

G4Apparently Secure Found in 7 roadless areas NatureServe Explorer →
G4Apparently SecureGlobal Rank
Least concernIUCN
MediumThreat Impact
Identity
Unique IDELEMENT_GLOBAL.2.102373
Element CodeARADB35070
Record TypeSPECIES
ClassificationSpecies
Classification StatusStandard
Name CategoryVertebrate Animal
IUCNLeast concern
Endemicoccurs (regularly, as a native taxon) in multiple nations
KingdomAnimalia
PhylumCraniata
ClassReptilia
OrderSquamata
FamilyColubridae
GenusTantilla
Concept Reference
Cole, C. J., and L. M. Hardy. 1981. Systematics of North American colubrid snakes related to Tantilla planiceps (Blainville). Bull. Am. Mus. Nat. Hist. 171:199-284.
Taxonomic Comments
Cole and Hardy (1981) greatly changed the circumscription of this species. Populations east of California that were formerly included in T. planiceps are now allocated to T. hobartsmithi, T. atriceps, or T. yaquia. Tantilla planiceps as currently defined includes T. eiseni, which was formerly recognized as a distinct species occurring in California and northern Baja California (see Cole and Hardy 1981).
Conservation Status
Rank Method Rank calculation - Biotics v2
Review Date2025-12-07
Change Date1996-10-30
Edition Date2025-12-07
Edition AuthorsHammerson, G. (2005); rev. R. L. Gundy (2025)
Threat ImpactMedium
Range Extent200,000-2,500,000 square km (about 80,000-1,000,000 square miles)
Number of Occurrences81 - 300
Rank Reasons
This species occurs along a broad range in western California south through the Baja California peninsula. Little is known about the population. Habitat loss due to urbanization is a localized threat.
Range Extent Comments
The range extends along the Coast Ranges from central California, just east (east of Livermore) and south of San Francisco Bay, to the tip of Baja California, ranging to the desert side of the mountains in southern California (Cole and Hardy 1981, Cole and Hardy 1983, Grismer 2002, Stebbins 2003, Wilson and Mata Silva 2015, Alvarez and Vang 2024). Elevational range extends from sea level to about 1,220 meters (4,000 feet) (Stebbins 2003).Using Global Biodiversity Information Facility (GBIF) (2025) records, range extent is estimated to be 304,673 km² (RARECAT 2025).
Occurrences Comments
Applying a 5 km separation distance to GBIF (2025) records, 192 occurrences are estimated (RARECAT 2025).
Threat Impact Comments
No major rangewide threats are known. Locally in southern California and the southern Baja Peninsula, some habitat has been lost to urbanization (Alvarez and Vang 2024). This species is projected to experience a northward range shift due to increasing temperatures (Pilliod et al. 2024).
Ecology & Habitat

Habitat

Habitats include grassland, coastal scrub, chaparral, oak and oak-pine woodland, desert-edge, and thornscrub, often in rocky areas and along streams, on both level ground and hillsides (Grismer 2002, Stebbins 2003). This snake stays underground or under rocks or other cover during daylight.

Reproduction

Lays a clutch of 1-3 eggs, May-June (Stebbins 1985).
Terrestrial Habitats
Woodland - HardwoodWoodland - MixedShrubland/chaparralGrassland/herbaceous
Palustrine Habitats
Riparian
Other Nations (1)
United StatesN4
ProvinceRankNative
CaliforniaSNRYes
Threat Assessments
ThreatScopeSeverityTiming
1 - Residential & commercial developmentRestricted (11-30%)Serious or 31-70% pop. declineHigh (continuing)
1.1 - Housing & urban areasRestricted (11-30%)Serious or 31-70% pop. declineHigh (continuing)
11 - Climate change & severe weatherPervasive (71-100%)Slight or 1-10% pop. declineHigh (continuing)
11.3 - Temperature extremesPervasive (71-100%)Slight or 1-10% pop. declineHigh (continuing)

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Roadless Areas (7)
California (7)
AreaForestAcres
Arroyo SecoAngeles National Forest4,703
Cucamonga AAngeles National Forest1,249
Cucamonga CSan Bernardino National Forest4,106
Eagle PeakCleveland National Forest6,481
LaddCleveland National Forest5,300
Lpoor CanyonLos Padres National Forest13,762
Strawberry PeakAngeles National Forest7,245
References (17)
  1. Alvarez, J. A. 2022. Natural history notes: <i>Tantilla planiceps</i> (western black-headed snake). Herpetological Review 53(3): 522.
  2. Alvarez, J. A., and C. D. Vang. 2024. Distribution of the western black-headed snake (<i>Tantilla planiceps</i>) in California: implications for management. Western North American Naturalist 84(2): 175–187.
  3. Cole, C. J., and L. M. Hardy. 1981. Systematics of North American colubrid snakes related to Tantilla planiceps (Blainville). Bull. Am. Mus. Nat. Hist. 171:199-284.
  4. Cole, C.J. and L.M. Hardy. 1983. <i>Tantilla planiceps</i>. Cat. Am. Amph. Rep. 319.1-319.2.
  5. 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.
  6. 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
  7. 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.
  8. 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]
  9. Ernst, C. H., and E. M. Ernst. 2003. Snakes of the United States and Canada. Smithsonian Books, Washington, D.C.
  10. Global Biodiversity Information Facility (GBIF). 2025. Global Biodiversity Information Facility (GBIF) data portal. Online. Available: https://www.gbif.org/ (accessed 2025).
  11. Grismer, L. L. 2002. Amphibians and reptiles of Baja California including its Pacific islands and islands in the Sea of Cortes. University of California Press, Berkeley. xiii + 399 pp.
  12. Lovich, R. E., L. L. Grismer, and G. Danemann. 2009. Conservation status of the herpetofauna of Baja California, México and associated islands in the Sea of Cortez and Pacific Ocean. Herpetological Conservation and Biology 4(3): 358-378.
  13. Pilliod, D. S., M. I. Jeffires, R. S. Arkle, and D. H. Olson. 2024. Climate futures for lizards and snakes in western North America may result in new species management issues. Ecology and Evolution 14: e70379. doi: 10.1002/ece3.70379
  14. <p>NatureServe's Rapid Analysis of Rarity and Endangerment Conservation Assessment Tool (RARECAT). 2025. Version: 2.1.1 (released April 04, 2025).</p>
  15. Stebbins, R. C. 1985a. A field guide to western reptiles and amphibians. Second edition. Houghton Mifflin Company, Boston, Massachusetts. xiv + 336 pp.
  16. Stebbins, R. C. 2003. A field guide to western reptiles and amphibians. Third edition. Houghton Mifflin Company, Boston.
  17. Wilson, L. D., and V. Mata Silva. 2015. A checklist and key to the snakes of the <i>Tantilla</i> clade (Squamata: Colubridae), with comments on taxonomy, distribution, and conservation. Mesoamerican Herpetology 2: 418–498.