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Rosy Boa Taxonomy By Jorden A Perrett
Rosy Boa Taxonomy

What is Taxonomy?
What is Taxonomy?

Taxonomy is an extremely important, though artificial tool we use as humans to discuss, describe, and observe the evolving diversity of the flora and fauna of our world. As we constantly adapt our classification model to fit our current understanding of what we observe, we quickly find limitations in our definitions. The idea of subspecies, which has long been an important part of the identification of the wildlife around us, is quickly becoming unpopular. As the definition of species fluctuates, the importance, or rather the validity of many current subspecies comes under scrutiny as they often are found to be based on traits that have more to do with what we see and less to do with the actual evolutionary relationships within the group. We are finding that many subspecies are worthy of elevation to species status, while others just represent simple variation and are being swallowed or lumped together under a broader more variable species.

Current technology and a great deal of change in the philosophies of the scientific community have opened our eyes and given us a greater view of this grand diverse world. Every day we find new relationships, and we occasionally need to make changes to the way we name what we see. It is increasingly important to understand that taxonomy is our invention of convenience and is indeed artificial and will continually change as we learn more about our world. That is not to say that our taxonomy model should be discarded, or that there is a better method of classification. We, as observers and students of nature, must evolve in our systems of understanding just as the world around us evolves daily. Taxonomy must be dynamic yet functional. To many hobbyists and outdoor enthusiasts, this process sounds unstable and can be difficult to follow, but nevertheless is a critical element of biology and conservation.


Charina or Lichanura?
Charina or Lichanura?

Charina bottae - Rubber boa
Img T.1 Rubber Boa - Charina bottae
With as many differences as similarities, Rubber boas are the closest relatives of the Rosy boa.
Being a genus with only one species, Lichanura has become a target of enthusiasts, hobbyists, and herpetologists as the constant battle for understanding has brought a great deal of revision to the group. The variations found within the genus have drawn a great deal of controversy over the years as there has been no thorough examination of the group, and this void has been filled with conjecture and opinion. Only through time and a great deal of effort will we be able to establish an agreeable classification that will properly demonstrate the relationships within this group of boas. The genus has been proposed as a synonym with Charina by Kluge (1993) as he demonstrated the close relationship between Lichanura, Charina, and the African Calabaria. For our purposes, the consolidation under Charina will not be used in an effort to better represent the evolutionary distinction within the group, though it is important to understand that there is indeed a very close tie amidst these 3 fascinating species. The sister species, Charina bottae will be discussed in further detail later.



Rosy Boa - Lichanura trivirgata (COPE 1861)

Aptly named, Lichanura trivirgata accurately describes this species. Lichan- is derived from the Greek word lichanos, meaning fore-finger and -oura meaning tail. The specific name trivirgata literally means three vertibral stripes. This species ranges from just west of Phoenix in Arizona to Coastal California and from as far north as Death Valley National Monument in California south to the peninsular tip of Baja California and the Mexican state of Sonora on the Mainland. They are found on at least a half of a dozen islands both in the Gulf of California and off of the Pacific Coast of Baja.


Rosy boas are currently separated into three recognized subspecies, with a fourth often used, especially amongst herpetoculturalists, to differentiate the beautiful Mid-Baja population. In time this may be accepted though currently it is not valid.


Mexican Rosy Boa - Lichanura trivirgata trivirgata (COPE 1861)

The nominate race is native to western Sonora, Mexico from Guaymas north through Organ Pipe Cactus National Monument to the Maricopa Mountains in Arizona, as well as the southern half of Baja California and surrounding islands. Dark chocolate to black, well defined stripes contrast against a cream to straw background. Width of the stripes varies from area to area, and also amongst individuals. Ventral pattern absent or restricted to random flecking of black against the cream colored venter.
L. t. trivirgata - Mexican Rosy Boa
Img T.2 Mexican Rosy Boa - L. t. trivirgata
Photo courtesy of Jeff Miller.

"Triv trivs" as they are affectionately known as to many hobbyists are a great first rosy. They are arguably the most robust, gentle and for good reason the most encountered rosy of the pet trade. These Mexican jewels do exceptionally well in captivity and appear to be more tolerant of less than ideal conditions. In general they are a smaller boa not achieving the lengths of the Arizona gracia and California roseofusca. Of course, there occasionally are captive individuals that rival any other Lichanura in terms of size and mass.


  1. Recently, this subspecies was found in the Maricopa mountains by Thomas C. Brennan, Phoenix, AZ, USA and Martin J. Feldner, Tempe, AZ, USA in 2001 representing a noteworthy range extension. Click here for more info...
  2. L. t. "bostici" has been used in the past to refer to the Cedros Island population but is not valid.

Desert Rosy Boa - Lichanura trivirgata gracia (KLAUBER 1931)
L. t. gracia - Desert Rosy Boa from Arizona
Img T.3 Desert Rosy Boa - L. t. gracia
A classic example of the arizona population of gracia.

Rumored to have been named in honor of his wife Grace, Lawrence Klauber described this "new" California boa in 1931. The much wider and occasionally jagged stripes of orange, rose, or burgundy are set against a tan to grey background. Reddish brown speckles ventrally and in Arizona populations often a great deal of black pigment bordering the lower lateral stripes and ventral flecking resembling "train tracks".

Inhabiting the desert mountain ranges of western Arizona and south eastern California from the Chocolate Mountains in Southern California north to the Darwin Plateau and adjacent Panamint Mountains of Death Valley National Monument and from as far west as Lake Isabella in Kern Co. and Joshua Tree National Park east to Kingman, AZ and the Weaver Mountains, these boas frequent nearly every outcrop and bolder strewn desert hillside and canyon, especially areas associated with springs and intermittent water.
L. t. gracia - Desert Rosy Boa
Img T.4 Desert Rosy Boa - L. t. gracia
A cleanly marked gracia from the low desert of California.

While the Arizona and Southern California populations do well in captivity, many of the high-desert California boas seem more prone to problems relating to humidity, heat, and feeding. The harsh environments that these boas thrive in receive virtually no rainfall annually and are subject to freezing winter temperatures and summer heat that can reach high into the 110s F. With a little extra care, these boas can thrive and with each succeeding generation tend to be less finicky and easier to maintain.


  1. The relationship of the high-desert boas to the low-desert/Arizona population will be discussed in further detail in the near future and will be linked to this page. Please check back for an update, or email me if you have anything to add or comment on, or would like a notification of the update.

Coastal Rosy Boa - Lichanura trivirgata roseofusca (COPE 1868)
L. t. roseofusca - Coastal Rosy Boa
Img T.5 Coastal Rosy Boa - L. t. roseofusca
The jagged, irregular striping is a distinguishing feature of the Coastal Rosy.

The most variable of Lichanura with jagged, broken, or indistinct stripes of reddish, orange or brown on a cream, bluish-grey, or muddy ground color. Individuals from coastal northern Baja north to coastal San Diego Co. are often dull and nearly a solid brown "unicolor" boa. Heading north to the San Gabriel and San Bernardino Mountains they become the more classic orange to reddish against a soft cream to grey background.

Coastal boas can be the most plain of the entire group, but many will rival even the beautiful Mid-Baja boas. From over 6000ft to sea level, these boas cover the widest range of habitat and accordingly vary a great deal from area to area in size, color, and temperament. Mountain populations tend to be the largest of the rosy boas attaining lengths near 4 ft in captivity, while most lowland locales produce more average sized individuals. Boas from the San Gabriels are often more flighty in the wild occasionally moving quickly using serpentine locomotion to quickly escape capture when discovered. The brightly colored pumpkin orange and cream boas from these areas have been prized among collectors and the beautiful result of selective breeding are often offered amongst hobbyists. Truly stunning animals!


  1. Many individuals from the Palm Springs, CA area north along the eastern edge of the San Bernardino Mountains look to have traits that may indicate intergradation between L. t. gracia and L. t. roseofusca in this corridor between the two subspecies. Also, it is probable that the more consistent striping and brighter colors of the San Bernardino and San Gabriel boas may well be the physical expression of the flow of genetic material between these two subspecies.
  2. At least three albino rosy boas have been found in 2 separate locations within roseofusca's range.
  3. It is thought that the lighter colors of the eastern desert populations coincide with the warmer environments that these boas inhabit as an adaptation in dealing with the heat of the low desert, as the coastal and more temperate areas produce darker, less contrasting individuals which would aid in thermoregulation via basking.

Mid-Baja Rosy Boa - Lichanura trivirgata ssp.

Though not currently a valid subspecies, it is still widely used to differentiate the colorful cleanly striped boas of Baja California Norte and adjacent islands from the jagged and somewhat duller roseofusca of the north and the nominate black and yellow Mexican boas to the south. Thin, rich chestnut, burgundy, red, or bright orange stripes stand out against a soft cream to grey ground color. Eyes are vivid and match the color of the dorsolateral stripes. Ventral pattern is absent or lightly flecked with the foreground color and flecks of black. This subspecies is the most stunning of the Lichanura with even the less vibrant individuals drawing the attention of all rosy enthusiasts. A brightly colored and well marked Mid-Baja boa is quite a sight to behold. Mid-Baja Rosy Boas make great captives and are highly regarded amongst hobbyists as the perfect mix of color, contrast, temperament and size.


  1. L. t. "myriolepis" and L. t. "saslowi" are often used interchangeably in the pet trade and amongst hobbyists referring to the Mid-Baja population or pattern class.



Klauber, Laurence M. 1931
A new subspecies of the California boa, with notes on the genus Lichanura.
Transactions of the San Diego Society of Natural History 6 (20): 305-318

Van Denburgh, John 1922
The Reptiles of Western North America.
California Academy of Sciences, San Francisco

Brian I. Crother, compiled by 2000
Scientific and Standard English Names of Amphibians and Reptiles of North American North of Mexico, with Comments Regarding Confidence in Our Understanding. .
Society for the Study of Amphibians and Reptiles

Cope, E.D. 1868
[Observations on some specimens of Vertebrata...; protocol of the Jan 21, 1868 meeting].
Proc. Acad. Nat. Sci. Philadelphia 20: 2

Cope, E.D. 1861
Contributions to the ophiology of Lower California, Mexico and Central America.
Proc. Acad. Nat. Sci. Philadelphia 13: 292-306

Stebbins, R.C. 1985
A Field Guide to Western Reptiles and Amphibians, 2nd ed.
Houghton Mifflin, Boston


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