A Guide to the Amphibians
and Reptiles of California

Baja California Ratsnake - Bogertophis rosaliae

(Mocquard, 1899)
Click on a picture for a larger view

Baja Rat Snake range map
Range in California: Red

Dot-locality range map

observation link

Baja Rat Snake Baja Rat Snake Baja Rat Snake
Very thin adult, Baja California. © Gary Nafis. Specimen courtesy of Victor Valasquez, El Serpentario de La Paz
Baja Rat Snake Baja Rat Snake Baja Rat Snake
Adult, Baja California © Jason Jones Adult, Baja California © Patrick Briggs Adult, Baja California.
© William Flaxington.
Specimen courtesy of El Serpentario de La Paz
Baja Rat Snake Baja Rat Snake  
Adult, Baja California, © Dick Bartlett
Juvenile, Baja California, © Dick Bartlett  
Possible Habitat in California
Baja Rat Snake Habitat Baja Rat Snake Habitat Baja Rat Snake Habitat
The Baja California Ratsnake is listed as present in California from only one specimen that was found dead on a road in Imperial County 2.4 miles east of Mountain Springs.*
These pictures show the wash and rocky habitat near that location.
Rumors that other Baja Ratsnakes have been found in California are unconfirmed.

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

Adults 34 -58 inches (85 - 152 cm) Averages 3 - 4 feet.

A slender snake with a long broad head distinct from the slender neck.
The eyes are large and protuberant.
Color and Pattern
Adults are nearly uniform in color with a brownish ground color and no dark markings.
Sometimes the dorsal scales appear to be edged with dark color.
The color lightens on the sides, and the underside is light with no pattern.
Young are pale with light streaks across back.

Life History and Behavior

Primarily nocturnal and crepuscular, but also observed active in daylight.
Probably active from late February through October in the northern part of its range.
A good climber.
A constrictor,
May strike viciously when threatened.
Diet and Feeding
Probably preys mostly on small mammals, but has also been found to consume bats and lizards.
Lays eggs which probably hatch from June through October.

Geographical Range
Listed as present in California from only one specimen that was found dead on Interstate Highway 8, 2-2/5 miles (3.84 km) east of Mountain Spring in Imperial County on May 26th 1984.

San Diego Natural History Museum Record:

Catalog Number: 64416
Latitude: 32.6465"
Longitude: -116.10508
Locality: Mountain Springs; 2.4 mi E of, on I-8 Imperial County, California
Date Collected: May 26th 1984
Collector: Unknown
Record: Preserved Specimen

South of California, this species occurs on the eastern slope of Baja California south to the entire cape region. Distribution is spotty and not well known throughout the northern part of its range.

The presence of this snake in California has been a popular topic of speculation and rumor among herpers, especially on the internet where unsubstantiated and unverifiable claims run rampant. Some question the validity of this record saying it could have been a dead snake (from a private collection or recently smuggled from Baja California) that was thrown on the freeway (maybe as a prank). Others say the habitat is marginal or too high in elevation for this species, and that since very few specimens have been found in Baja California near the California border, it is unlikely the species ranges as far north as California. Some veteran California herpers say they have searched in vain for this snake in California for many years but found them not too far south of the border.

Others believe the record is valid and that more specimens have not been found because few people go into suitable habitat in the area anymore due to the the current California/Mexican border war zone situation involving illegal immigrants and drug smugglers and the Border Patrol. (The Border Patrol ran me down with a helicopter and 5 vehicles once just for driving a dirt road near the border.) The rough terrain also discourages hunting. The difficulty of searching for snakes on a busy freeway is also mentioned. Since the species is protected by the state, anyone who finds (and presumably illegally collects) this snake in California will never report their find or deposit a specimen in a museum, so we will never get an accurate report on the abundance of this species in the state.

One argument (attributing data to Lee Grismer, the author of the definitive book on the herpetofauna of Baja California), claims there is scientific proof because the lateral scale count is highest and the scale size is smallest for this species at the southernmost part of its range, and that the scale count decreases and the scale size increases in specimens as you travel north. Since the California specimen has the lowest lateral scale count and largest scale size recorded for this species (even lower and larger than those of northern Baja California) it makes sense that the snake comes from the northernmost part of its range.

There is no doubt that there will be many more arguments for and against the occurance of the snake in the state as this lively discussion continues.

Full Species Range Map
Associated with dry rocky habitats in Baja California, including canyons, bajadas, thorn scrub, palm groves, springs and streams.

Notes on Taxonomy
Alternate and Previous Names (Synonyms)

Bogertophis rosaliae - (Mocquard, 1899, Stebbins 2003, 2012)

Conservation Issues  (Conservation Status)
A California Species of Special Concern.
Family Colubridae Colubrids Oppel, 1811
Genus Bogertophis Desert Ratsnakes Dowling and Price, 1988

rosaliae Baja California Ratsnake (Mocquard, 1899)
Original Description
Bogertophis rosaliae - (Mocquard, 1899) - Nouv. Arch. Mus. Hist. Natur. Paris, 4th Series, Vol. 1 (2nd fasc), p. 321

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

Meaning of the Scientific Name
Bogertophis - honors Bogert, Charles M.
- refers to the type locality- Santa Rosalia, Baja California Sur, Mexico

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

Related or Similar California Snakes
There are no similar or related snakes in the potential range for this snake, but under some conditions, for example at a distance on a road at night, these snakes, and possibly others, might be confused for the Baja California Ratsnake:

Masticophis flagellum piceus - Red Coachwhip
Arizona elegans eburnata - Desert Glossy Snake
Pituophis catenifer annectens - San Diego Gophersnake
Salvadora hexalepis hexalepis - Desert Patch-nosed Snake

More Information and References
California Department of Fish and Wildlife

Jennings, Mark R. and Marc P. Hayes. Amphibian and Reptile Species of Special Concern in California. California Department of Fish and Game, published November 1, 1994.

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, 1957.

Grismer, L. Lee. Amphibians and Reptiles of Baja California, Including Its Pacific Islands and the Islands in the Sea of Cortés. The University of California Press, 2002.

McPeak, Ron H. Amphibians and Reptiles of Baja California. Sea Challengers, 2000.

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.

Status Listing
NatureServe Global Ranking G4 Apparently Secure—Uncommon but not rare; some cause for long-term concern due to declines or other factors.
NatureServe State Ranking S1

Critically imperiled in the state because of extreme rarity (often 5 or fewer populations) orbecause of factor(s) such as very steep declines making it especially vulnerable to extirpation from the state.

U.S. Endangered Species Act (ESA) None
California Endangered Species Act (CESA) None
California Department of Fish and Wildlife WL Watch List
Bureau of Land Management None
USDA Forest Service None
IUCN LC Least Concern


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