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A Guide to the Amphibians
and Reptiles of California


Northern Rubber Boa - Charina bottae

(Blainville, 1835)
Click on a picture for a larger view



Rubber Boas California Range Map
Red: Northern Rubber Boa

Blue: Southern Rubber Boa

Orange: area where the species of rubber boa
is recognized as potentiially Southern Rubber Boa by the CDFW.

Purple: Area representing recently-discovered
boas of unexamined species, most likely Northern Rubber Boa.







observation link





Northern Rubber Boa
Northern Rubber Boa Northern Rubber Boa Northern Rubber Boa Northern Rubber Boa
Adult, Napa County in situ, mid afternoon
(stretched out on log bottom left)
Adult, Santa Cruz County
Northern Rubber Boa Northern Rubber Boa Northern Rubber Boa Northern Rubber Boa
  Adult, 8,000 ft., Alpine County   Adult, Del Norte County © Alan Barron
Northern Rubber Boa Northern Rubber Boa Northern Rubber Boa Northern Rubber Boa
  Large old scarred adult, Marin County   Adults, Marin County
Northern Rubber Boa Northern Rubber Boa Northern Rubber Boa Northern Rubber Boa
  Adult, Marin County   Dark adult, Marin County
© Luke Talltree
Northern Rubber Boa Northern Rubber Boa Northern Rubber Boa Northern Rubber Boa
Adult male, Contra Costa County Dark adult, Marin County. © Natalie McNear
Northern Rubber Boa Northern Rubber Boa Northern Rubber Boa Northern Rubber Boa
Adult, Santa Cruz County
© Gary Nafis
Specimen courtesy of Mitch Mulks
This adult snake from El Dorado County has colorful eyes. © Richard Porter Adult, ready to shed, Marin County Underside of adult, Marin County
Northern Rubber Boa Northern Rubber Boa Northern Rubber Boa Northern Rubber Boa
Adult with unusual black eyes, San Mateo County © Natalie McNear Adult with unusual black eyes, San Mateo County © Chad M. Lane Adult, Santa Cruz County © Zach Lim Adult, Sierra County.
© 2005 Jackson Shedd,
Specimen courtesy of John Stephenson
Northern Rubber Boa Northern Rubber Boa Northern Rubber Boa Northern Rubber Boa
Adult, Fresno County
© Patrick Briggs

Adult, Butte County © Jackson Shedd Adult, Alameda County © Ben Witzke Adult, Santa Lucia Mountains, Monterey County © Benjamin German
Northern Rubber Boa Northern Rubber Boa Northern Rubber Boa Northern Rubber Boa
When threatened, Rubber Boas will often roll into a ball, hide their head and elevate the tip of their taill to fool a predator into attacking the tail which looks somewhat like a head. The tail is less-vulnerable than the head and can withstand attacks without much damage. Some boas have many scars on the tail from this tactic. You can see this behavior in the video below. Adult found at 7,825 feet elevation in Inyo County. © Jason Fitzgibbon
Northern Rubber Boa Northern Rubber Boa Northern Rubber Boa Northern Rubber Boa
Sub-adult, San Mateo County Group of adults, Marin County
© Chad Lane
In winter, it is not uncommon for several snakes, including multiple species, to share the same shelter. 8 boas were found under the same board along with a few Coast Gartersnakes.
Rubber Boa skeleton, showing the enlarged tail tip.
National Museum of Natural History
       
Juveniles
Northern Rubber Boa Northern Rubber Boa Northern Rubber Boa Northern Rubber Boa
Neonate, Butte County © Jackson Shedd Juvenile, Madera County
© Patrick Briggs
Juvenile, Contra Costa County Juvenile, Butte County © Rodney Lacey
Northern Rubber Boa Northern Rubber Boa Northern Rubber Boa Northern Rubber Boa
Juvenile, Kittitas County, Washington
Juvenile from 7,200 ft. in northern Inyo County © Keith Condon
Northern Rubber Boa Northern Rubber Boa Northern Rubber Boa Northern Rubber Boa
  Juvenile, Marin County   Sub-adult, San Mateo County
       
Habitat
Pacific Ring-necked Snake Habitat Northern Rubber Boa Habitat Northern Rubber Boa Habitat Northern Rubber Boa Habitat
Habitat, Contra Costa County Habitat, San Mateo County Habitat, Napa County Habitat, Tuolumne County
Coast Mountain Kingsnake Habitat Northern Rubber Boa Habitat Northern Rubber Boa Habitat Northern Rubber Boa Habitat
Habitat, 2,500 ft. Santa Cruz Mountains, Santa Clara County Habitat, 8,000 ft., Alpine County Habitat, Marin County Habitat, Santa Cruz County
Northern Rubber Boa Habitat Northern Rubber Boa Habitat Northern Rubber Boa Habitat Northern Rubber Boa Habitat
Habitat, San Mateo County Habitat, lava bed caves at around 4,500 ft. elevation in the Great Basin desert of Siskiyou and Modoc counties. Rubber boas are sometimes seen crawling on rocks inside these caves, where the average temperature is reported as 55 degrees.
Northern Rubber Boa Habitat Coast Mountain Kingsnake Habitat Coast Range Fence Lizard Habitat
Habitat, Butte County © Rodney Lacey Habitat, Santa Cruz Mountains,
Santa Cruz County
Habitat, Contra Costa County
Habitat, Santa Cruz Mountains
© Zachary Lim

More pictures of this snake and its natural habitat are available on our Northwest Herps page.

Short Videos
Northern Rubber Boa Northern Rubber Boa Northern Rubber Boas  
It was 55 degrees F.around 8 PM at about 8,000 ft. elevation on a mountain pass in Alpine County when I saw this rubber boa crossing the road. It eventually dropped down a huge tree stump to get away from me and curled up under some tree bark.
As you can see in this video, when they feel threatened, Northern Rubber Boas often curl into a ball with their head hidden in the middle and the tail on the outside, elevated like a head, which it resembles. When a predator attacks what it thinks is a head, it will only injure the tail, which is much less life threatening to the snake. Many rubber boas have scars on their tails from such attacks Natalie took Chad and myself to look under a board she found in Marin County that is used as a shelter by at least 8 rubber boas. When Chad lifts it, we see 7 boas and a Coast Gartersnake.  
     
Description

Not Dangerous (Non-poisonous)  -  This snake does not have venom that is dangerous to most humans.

Size
Adults 15 - 33 inches (35 - 84 cm.) Typical size of adults is 15 - 25 inches. Newborns 7.5-9 inches.
Small or dwarf populations have been found in the Tehachapi, Greenhorn and Paiute Mountains, on Breckenridge Mountain, and on Mt. Pinos.

Appearance
A small constrictor with a stout body and a thick tail with a blunt end (that looks a bit like a head), and smooth shiny small-scaled loose and wrinkled skin, which gives the snake a rubbery look and feel.
Eyes are small with vertically elliptical pupils.
Color and Pattern
Light brown, dark brown, pink, tan, or olive-green above, and yellow, orange, or cream colored below.
Usually uniform in color on the back, but sometimes dark spots or mottling occur, especially in northern populations, possibly due to scarring.
Usually no pattern below, but sometimes there is dark mottling.
Young
Young snakes are pink or tan, and can be brightly-colored.

Life History and Behavior

Activity
Nocturnal and crepuscular, sometimes active in daylight.
Sometimes active in weather that would be too cold for most reptiles, with surface temperatures in the 50s.
A good burrower, climber and swimmer.
Often found under logs, boards and other debris, sometimes on roads at dusk.
Defense
The tail is short and blunt and looks like a head.
When threatened, the snake hides its head in its coiled body, and elevates the tail to fool an attacker into attacking the tail. Snakes with scarred tails are common.
Longevity
Known to live as long as 40 - 50 years in the wild.
Diet and Feeding
Eats small mammals, birds, salamanders, lizards, and snakes, possibly frogs.
Breeding
Bears 1 - 9 live young from August to November.

Geographical Range
Found from northern Monterey County north along the coast ranges into the Siskiyou Mountains and the northern Great Basin and south to the southern Sierra Nevada Mountains, including the east side to south of Mono Lake. Absent from the Great Valley and deserts.

Ranges out of California in Oregon, Washington, northwest Canada, Nevada, Idaho, Utah, Wyoming and Montana. (See map below.)


Since the species of Charina occuring 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 2004 document (which has now been removed):

"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 apply only to the Mt. Pinos Kern County population.


Richard Hoyer has made extensive studies of Charina. His position on the distribution of the Southern Rubber Boa (SRB) was explained to me in a peronal communication:

"The only valid Scientific study that identifies the distribution of the SRB is the 1943 paper by L. Klauber in which he proposed adoption of the new SRB subspecies. That is, the SRB only occurs in the San Bernardino and San Jacinto Mts."
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. Until that evidence is found and published, I will continue to show the ranges of Charina in California according to the CDFW interpretation because C. umbratica is a protected species.
NatureServe Explorer   Accessed 1/10/15.

Charina umbratica - Klauber, 1943 Southern Rubber Boa Distribution:

"Global Range: (1000-5000 square km (about 400-2000 square miles)) Range encompasses the San Bernardino Mountains and San Jacinto Mountains of southern California; populations in the Tehachapi Mountains and Mount Pinos area have some umbratica characterisitcs but are included in the C. bottae (northern rubber boa) clade (Rodriguez-Robles et al. 2001, Stebbins 2003). Elevational range is 1,540-2,460 meters (Stewart 1988). Twenty-six of the 40+ localities in the San Bernardino Mountains are in a 16-kilometer strip between Twin Peaks on the west and Green Valley on the east (Stewart 1988). Extent of occurrence is less than 5,000 square kilometers."

Full Species Range Map
Elevational Range
From sea level to over 10,000 ft. elevation.

Habitat
Grassland, mountain meadows, chaparral, woodland, along streamsides, deciduous and coniferous forest.

Notes on Taxonomy
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.
IUCN Charina bottae Taxonomy Notes
Published in 2007.   Accessed 1/10/15

"Nussbaum and Hoyer (1974) showed that subspecies utahensis is indistiguishable from subspecies bottae, and they regarded the concept "umbratica" as meaningless; Collins (1990) apparently agreed with this view and did not recognize any subspecies. In contrast, Erwin (1974) proposed that subspecies umbratica warrants species status; this suggestion did not gain the support of other herpetologists. Stewart (1977) recognized two subspecies (bottae and umbratica) and, pending further study, regarded populations from Mt. Pinos and the Tehachapi Mountains, California, as intergrades between these two subspecies. Stebbins (1985) continued to recognize three subspecies (bottae, utahensis, and umbratica). Rodriguez-Robles et al. (2001) used mtDNA data to examine phylogeography of C. bottae and concluded that "C. b. umbratica is a genetically cohesive, allopatric taxon that is morphologically diagnosable" [using a suite of traits] and that "it is an independent evolutionary unit that should be recognized as a distinct species, Charina umbratica". The authors acknowledged that a mixture of bottae and umbratica traits exists in populations in the Tehachapi Mountains and Mount Pinos, but they interpreted this as persistent ancestral polymorphisms. They also found no support for recognizing utahensis as a valid taxon. Crother et al. (2003) listed C. umbratica as a species whereas Stebbins (2003) mentioned the proposal but did not adopt the split. In this database we maintain umbratica as a subspecies of C. bottae until a concensus on the taxonomy of this group emerges."
Notes from SSAR Herpetologican Circular No. 39, 2012:

"Kluge (1993, Zool. J. Linn. Soc. 107: 293-351) placed Lichanura in the synonymy of Charina because they formed sister taxa. Burbrink (2005, Mol. Phylogenet. Evo. 34: 167-180) corroborated the relationship found by Kluge. However, Rodriguez-Robles et al. (2001, Mol. Phylogenet. Evol. 18:227-237) found C. b. umbratica to represent a morphologically distinct, allopatric lineage that they elevated to species status based on mitochondrial sequences, along with allozyme data from a previous study (Weisman, 1988, MS Thesis, CSU Polytechnic Pomona). With the recognition of C. umbratica and fossil species referred to both Charina and Lichanura (Holman, 2000, Fossil Snakes of north America, Indiana Univ. Press) neither genus is monotypic and they are treated here as separate genera."

Conservation Issues  (Conservation Status)
None
Taxonomy
Family Boidae Boas and Pythons Gray, 1842
Genus Charina Rubber Boas (Gray 1849)
Species


bottae Northern Rubber Boa  (Blainville, 1835)
Original Description
Charina bottae - (Blainville, 1835) - Nouv. Ann. Mus. Hist. Nat. Paris, Vol. 4, p. 289, pl. 26, figs. 1, 1B

from Original Description Citations for the Reptiles and Amphibians of North America © Ellin Beltz

Meaning of the Scientific Name
Charina - Greek -charieis - graceful, delightful
bottae
- honors Botta, Paolo E.

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

Alternate Names
Rubber Boa
Coastal Rubber Boa
Charina bottae bottae

Related or Similar California Snakes
C. umbratica - Southern Rubber Boa
L. t. roseofusca - Coastal Rosy Boa

More Information and References

California Department of Fish and Wildlife


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.

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.

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

Brown et. al. Reptiles of Washington and Oregon. Seattle Audubon Society,1995.

Nussbaum, R. A., E. D. Brodie Jr., and R. M. Storm. Amphibians and Reptiles of the Pacific Northwest. Moscow, Idaho: University Press of Idaho, 1983.

St. John, Alan D. Reptiles of the Northwest: Alaska to California; Rockies to the Coast. Lone Pine Publishing, 2002.

Conservation Status

The following status listings come from the Special Animals List and the Endangered and Threatened Animals List which are published by the California Department of Fish and Wildlife.


This snake is not included on the Special Animals List, which indicates that there are no significant conservation concerns for it in California.
Organization
Status Listing
NatureServe Global Ranking
NatureServe State Ranking
U.S. Endangered Species Act (ESA) None
California Endangered Species Act (CESA) None
California Department of Fish and Wildlife None
Bureau of Land Management None
USDA Forest Service None
IUCN

 

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