Southern Rubber Boa - Charina umbratica

When threatened, the snake hides its head in its coiled body, and elevates the tail to fool the predator into attacking the tail. Snakes with scarred tails are common.

Endemic to California.

The range of this species is unclear and somewhat controversial because of its protected status.
It is definitely found in a few disjunct areas in montane southern California in the San Bernardino and San Jacinto Mountains. (Oddly, it is missing from the San Gabriel Mountains, where the habitat appears to be the same.) Boas occurring in the southern Sierra Nevada, the Tehachapi Mountains, and on Mt. Pinos, Mt. Abel, Mt. Alamo, and Frazier Mountain are protected as C. umbratica by the California Department of Fish and Wildlife. Nevertheless, their species status is still unclear. Pending more DNA studies, these could turn out to be C. umbratica or C. bottae or hybrids.

Since the species of Charina occurring in the southern Sierra Nevada, the Tehachapi Mountains, Mt. Pinos, and in San Luis Obispo County has not been determined, and because C. umbratica is a species protected by the state, I will show a separate area in purple on my range map of Charina that are of unknown species, and another in orange of Charina that appear to be classified as C. umbratica by the CDFW, until I learn of new scientific studies that change this.

1/15

Rubber boas were found in 2006 and 2010 at Montana de Oro on the coast of San Luis Obispo County, with photo confirmation in 2010. It seems most likely they would be C. bottae, but Stebbins & McGinnis (2012) state that C. umbratica occurs in the "northern part of the South Coast Range" which should include Montana de Oro, but until someone gets a permit to take a DNA sample from one of these snakes, which are found in a State Park, then finds another snake (which is not easy) and gets the sample tested, the species will remain unknown.

Description of the range of C. umbratica from  Stebbins, Robert C., and McGinnis, Samuel M. Field Guide to Amphibians and Reptiles of California: Revised Edition (California Natural History Guides) University of California Press, 2012 :

"C. umbratica is found in the northern part of the South Coast Range and at selected sites in Kern, San Bernardino, and Riverside Counties. These include Mount Pinos, Mount Abel, and the Tehachapi, San Bernardino, and San Jacinto mountains…."

The California Departent of Fish and Wildlife described the range of the Southern Rubber Boa (Charina umbratica) in a
Status of Rare, Threatened, and Endangered Plants and Animals of California 2000-2004 document (download the Reptiles PDF).

"The southern rubber boa is known from several localities in the San Bernardino Mountains in San Bernardino County, near Idyllwild in Riverside County, and on Mount Pinos in Kern County.

Recent genetic studies support separation of the southern rubber boa from all other populations of rubber boa. The subspecies appears to have diverged from the more widespread rubber boa between 12.3 and 4.4 million years ago. Possible intergrades between the southern rubber boa and the rubber boa found in the Tehachapi Mountains and on Mt. Pinos warrant further study."

No other CDFW documents that I can find as of 1/15 mention boas in the Tehachapi Mountains or in the Southern Sierra Nevada in their range descriptions. The most current fishing regulations protect all Kern County boas from take, but that could be because of the Mt. Pinos Kern County population.

MtDNA work has shown that most (but not all) Charina in the southern Sierra Nevada and the Tehachapis are more closely related to Charina bottae than to Charina umbratica.

"Morphologically, the Kern Plateau, Breckenridge Mountain, Piute Mountains, Scodie Mountains, and Tehachapi Mts populations all are comprised of "dwarf-morph" snakes [similar to C. umbratica] but that trait does not track with the mtDNA." (R.Hansen Pers. Comm. 4/13)  Because the morphology does not correspond to the mtDNA findings, there is not enough evidence to support an argument that these populations belong to either species.

First described by Laurence M. Kaluber in 1943 as Charina bottae umbratica subsp. nov. Southern California Rubber Snake

Formerly, one species of Charina was recognized, Charina bottae, which was comprised of three subspecies:
C. b. bottae - Northern Rubber Boa,
C. b. umbratica - Southern Rubber Boa, and
C. b. utahensis - Rocky Mountain Rubber Boa.

Some herpetologists still only recognize only one species - Charina bottae, with either no subspecies or with two subspecies -
C. b bottae - Northern Rubber Boa
C. b umbratica - Southern Rubber Boa.

Others recognize two full species of Charina, as is done by the California Department of Fish and Wildlife, the SSAR, the CNAH, and here -
Charina bottae - Northern Rubber Boa
Charina umbratica - Southern Rubber Boa.

Charina - Greek -charieis - graceful, delightful

from Scientific and Common Names of the Reptiles and Amphibians of North America - Explained © Ellin Beltz

umbratica - Latin - umbraticus - belonging to shade, belonging to seclusion

from Jaeger, Edmund C. A Source-book of Biological Names and Terms Third Edition. Charles C. Thomas Publisher, 1962.

California Department of Fish and Wildlife

Klauber, Laurence M. The Subspecies of the Rubber Snake, Charina. Transactions of the San Diego Society of Natural History Vol. X, No. 7, pp. 83-90 December 30, 1943.

Stebbins, Robert C., and McGinnis, Samuel M.  Field Guide to Amphibians and Reptiles of California: Revised Edition (California Natural History Guides) University of California Press, 2012.

Stebbins, Robert C. California Amphibians and Reptiles. The University of California Press, 1972.

Flaxington, William C. Amphibians and Reptiles of California: Field Observations, Distribution, and Natural History. Fieldnotes Press, Anaheim, California, 2021.

Samuel M. McGinnis and Robert C. Stebbins. Peterson Field Guide to Western Reptiles & Amphibians. 4th Edition. Houghton Mifflin Harcourt Publishing Company, 2018.

Stebbins, Robert C. A Field Guide to Western Reptiles and Amphibians. 3rd Edition. Houghton Mifflin Company, 2003.

Behler, John L., and F. Wayne King. The Audubon Society Field Guide to North American Reptiles and Amphibians. Alfred A. Knopf, 1992.

Powell, Robert., Joseph T. Collins, and Errol D. Hooper Jr. A Key to Amphibians and Reptiles of the Continental United States and Canada. The University Press of Kansas, 1998.

Bartlett, R. D. & Patricia P. Bartlett. Guide and Reference to the Snakes of Western North America (North of Mexico) and Hawaii. University Press of Florida, 2009.

Bartlett, R. D. & Alan Tennant. Snakes of North America - Western Region. Gulf Publishing Co., 2000.

Brown, Philip R. A Field Guide to Snakes of California. Gulf Publishing Co., 1997.

Ernst, Carl H., Evelyn M. Ernst, & Robert M. Corker. Snakes of the United States and Canada. Smithsonian Institution Press, 2003.

Taylor, Emily. California Snakes and How to Find Them. Heyday, Berkeley, California. 2024.

Wright, Albert Hazen & Anna Allen Wright. Handbook of Snakes of the United States and Canada. Cornell University Press, 1957.

Thelander, Carl G., editor in chief. Life on the Edge - A Guide to California's Endangered Natural Resources - Wildlife. Berkeley: Bio Systems Books, 1994.

Mitochondrial DNA-Based Phylogeography of North American Rubber Boas, Charina bottae (Serpentes: Boidae)
Molecular Phylogenetics and Evolution Vol. 18, No. 2, February, pp. 227–237, 2001

Joseph Grinnell and Charles Lewis Camp. A Distributional List of the Amphibians and Reptiles of California. University of California Publications in Zoology Vol. 17, No. 10, pp. 127-208. July 11, 1917.