Rosy Boa

(Lichanura trivirgata ssp.)

Native Range:

The Rosy Boa (Lichanura trivirgata) is found in the southwestern United States, from California eastward to Arizona. Additional populations are found from California south throughout the Baja peninsula and in adjacent areas of mainland Mexico. There they inhabit rocky desert regions. Several subspecies have been described, including L. t. trivirgata, L t. myriolepis, L. t. gracia, L. t saslowi, L. t. rosefusca, L. t. bostici and others. All of these are in dispute among taxonomists, and assigning an exact subspecific epithet to any individual form is as much based on locality and descriptive information as it is choosing an author whose work you believe in and following his guidelines! As a result, most hobbyists now maintain these snakes in locality pure lineages. Thus, if you know your snake comes from genetic stocks originating in a given locality, you can assign the correct nomenclature to it whenever scientists finally agree upon exactly what that should be.


Approximately eight to ten inches long at birth, they average two to three feet in length as adults. Most specimens fall towards the lower part of the size range, with those specimens from California's coastal areas tending to be the largest.


Rosy Boas rarely attempt to bite, although they may do so if restrained. Handle gently, without pinching or squeezing, allowing the snake to move through your fingers. Do not allow the snake to dangle unsupported. Rosy Boas have very strong reflexive feeding tendencies, believed to stem from their habits of feeding on lizards in rock cracks at night. They have strong tactile sensation along the sides, particularly toward the neck, and reaching into a cage and touching a sleeping Rosy Boa may result in an immediate reflexive feeding response. In simple terms, you should let them know you are there before picking them up or you may get bitten!


Any ‘typical’ snake cage can be used, with a ten or fifteen-gallon aquarium being adequate for an adult. Rosy Boas are crevice dwellers, and appreciate a secure hiding spot.


A variety of substrates can be used. Aspen bedding, newspaper, and Care Fresh are popular with many keepers. Paper towels may be used for lining baby cages. Keep the substrate clean and dry at all times. As with all reptiles, do NOT use cedar or pine shavings. These items are toxic to reptiles.


Most Rosies will be fed a diet of mice throughout their lives. Hatchlings usually feed readily on newborn ‘pinkie’ mice, and should be fed about every five to seven days. Increase the size of the meal as the snake grows. One or two adult mice are sufficient every ten or fourteen days to maintain even the largest adult. An occasional stubborn hatchling will require a pinkie scented with lizard smell (Anolis sp. seem to work well) before accepting it. These animals will often feed readily if left overnight in a small deli cup with a pinkie and a folded paper towel to hide under.

Humidity & Water:

Many supposed 'expert' keepers will flatly claim that Rosy Boas should not be allowed access to water at all times. They claim that the resulting high humidity is fatal to the snakes, causing respiratory problems. While this may be the case in areas of the country with a high relative humidity, it is definitely false here in Colorado's dry air. We have provided our Rosy Boas with clean water in a small dish for their entire lives and have lost only a single specimen to respiratory problems in fifteen years. (This one spilled the dish during brumation) However, we do agree that humidity should be kept very low.

Heating & Lighting:

Provide a thermal gradient by placing a heat pad under one end of the cage. This should allow the snake to choose from higher temperatures (about 85-90F) at the warm end, and cooler temperatures (about 70-75F) at the cooler end. Provide suitable hiding areas at both warm and cool areas, so the snake can feel secure at any temperature. Temperatures below 75F should be avoided. No special lighting is required for these nocturnal animals.


While all Rosy Boas can be accurately sexed by probing, many can be accurately sexed simply by checking for the presence of tiny 'spurs' on either side of the vent. These 'vestigial legs' are nearly always absent in females. Hatchlings can also be sexed by manually everting the hemipenes (a process known as ‘popping’). Probing or popping should only be performed by an experienced individual, as improper technique may result in severe damage or even death. Most specimens will require brumation (hibernation) to breed, but some Rosy Boas readily reproduce under normal conditions. Like all boas, the Rosy Boa is ovoviviparous, producing live young in late summer. Typical litters consist of about four to twelve offspring, although larger litters are recorded.

Color and Pattern Phases:

The many 'named' localities of the Rosy Boa are quite variable in appearance, and a collection of the various forms presents a rainbow of colors. Additionally, there are at least two forms of albinism known. Hypomelanistic and anerythristic individuals are well represented in North American collections as well, and should soon lead to a few interesting genetic combinations. A full-scale breeding operation to maintain and create all of these varieties (and many not yet created) would consist of several hundred breeders, and would take a lifetime to assemble. Many dedicated hobbyists have done just that.

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