Melissa Kaplan's
Herp Care Collection
Last updated January 1, 2014

Rosy Boa

Charina (=Lichanura) trivigata spp.

©1995 Melissa Kaplan

Rosy boas are one of the smaller members of the boa family. Like many boas and pythons, they are nocturnal (sometimes crepuscular), thus moving around mostly at night or around dawn and dusk. Rosys may live in excess of 15 years. Their name comes from Lichan = forefinger (Gr.(=) and - oura = tail, possibly due to the bluntness of their tail. Trivirgata refers to their prominent triad of stripes.

There are currently four subspecies of rosy boas; as with the classification of many animals, the taxonomists frequently dispute the species and subspecies designations. As more information is learned about the physiognomy and range of the animals in question, these may change Currently, the subspecies designations for the rosy boas are:

C. trivirgata Rosy Boa. to 40 in (100 cm). Ranges through southwestern U.S. (Southern California, Arizona, and northern Mexico). Ground color slate gray or brown.

L. t. bostici Mexican Rosy Boa. Ground color laced with pale, creamy broad longitudinal stripes. (Or, L. t. bostici = Cedros Island Rosy Boa and L. t. trivigata = Mexican Rosy Boa)

L. t. roseofusca Coastal Rosy Boa. Ground color laced with blotchy reddish-brown longitudinal stripes.

L. t. gracia Desert Rosy Boa. Ground color laced with well-defined pink, orange or tan longitudinal stripes.

Rosys look much like their cousins, the Rubber boa (Charina bottae). Rosy heads are set off slightly more from their bodies, and the tops of their heads are covered with numerous small scales, rather then the fewer, but much larger, scales of the Rubber boa. Rubber boas have blunt, rounded tails while the Rosy tails are more tapered, ending in a rounded tip.

Housing
Rosys range in size from 2-3 feet (never more than 4 feet) in overall length and can thus easily be housed in a 20 gallon enclosure. They do not climb much, needing only low branches, so a tall enclosure need not be provided as for the more arboreal boas. Provide bark slabs or half-logs for caves as an occasional alternative to substrate burrowing.

Substrate
Rosys like it dry. Their native habitat is mostly warm savannahs that experience little rainfall. Although they are not desert dwellers, they need to be kept in a dry tank like a desert dweller. Substrates such as cypress mulch, aspen, small wood chips work well. Rosys are burrowing snakes, so the substrate must be layered to a depth of at least 2-4 inches. Plain paper may be used but small hide boxes (big enough for the snake to get into but not so big that they can't feel it around them) will have to be provided on both sides of the temperature gradient.

Humidity
If you live in an area of higher humidity than their native range (60%), you should consider an enclosure with a top or one or two sides made of mesh, or that has solid sides with ventilation panels that may be opened and closed as necessary to keep in warms but provide enough ventilation to keep humidity levels down. In such climates, substrates such as the mulch and aspen may not be suitable as they tend to maintain a slightly higher humidity level than do wood chips. Being kept in humidity higher than they are adapted to can cause skin problems (bacterial or fungal infections) and the stress of being kept in such conditions may lead to illness.

Water
You can provide a water bowl provided the snake is not able to tip it over and that you do not fill it up so high that if the snake climbs into it to soak it will not overflow. On the whole, bowls with less surface area of exposed water will evaporate more slowly than bowls allowing for a wide expanse of exposed water surface.

Temperatures
Rosys are from warm, but not desert climates (except the Desert Rosy). 73-83 F (23-28 C) temperature gradients will work well through most of the year. Night time temps can drop slightly. Rosys spend most of their time underground where the temperatures are more constant than they are above ground. Provide heat by use of an undertank heating pad under one-half of the tank. If additional heat is necessary during the winter months, you may use an overheat heat source. If you need to use the overhead source at night, make sure it is not a white light bulb; use a dim red, blue or one of the nocturnal lights made especially for reptiles, or a ceramic heating element. Be sure to monitor the temperatures to be sure they do not rise over or fall under the temperature gradient.

Feeding
Many snakes can take in surprisingly large (for their body and head size) prey. Rosys have a relatively small gape, however, and so need to be fed small prey items. Captive bred Rosys are easily fed on killed mice, with young started out on pinkies, moving up to adult mice when they are full grown. Young should be fed once or twice a week, adults once every 7-10 days. Given their nocturnal habits, they are best fed at night.

Breeding
To ensure successful breeding, Rosys should be hibernated during the winter. Starting in November, feeding should be stopped. A couple of weeks later, after the snake has defecated out the remains of its last meal, the temperatures gradually reduced so that by December the enclosure is at 55 F (13 C). Maintain this temperature for about 12 weeks (until March). Allow to come gradually to room temperature, then warm slowly up to the normal temperature gradient. Begin weekly or more frequent feedings, especially of the females. House males and females separately.

In April, place the male into the female's enclosure. After about a week or so of mating, return the male to his enclosure. Add a warmer basking area to the female's enclosure, up to 86 F (30 C) and maintain that throughout the pregnancy. Expect that the female will not eat much--or at all--during this time.

Birth will generally occur in September. Five to six live young (as many as 13 have been reported), each about 12 inches in overall length, will be born. The babies are active, often feisty, but bites should not be of concern. Babies should be removed from the mother shortly after birth.

After their first shed, which may occur as soon as two days after birth or as long as two weeks later, feed the babies pinkies. Some have reportedly fed prior to their first shed; if they are particularly feisty or appear to be seeking, try offering them food sooner. Remember: if you are housing them together you must separate them at feeding time!

Some may not feed at all at this time: in the wild, they are born just before the winter sets in, and in the wild many such late-season babies do not eat at all, going right into hibernation for the winter, emerging in the spring ready to feed. If they are not losing body mass or weight while not feeding, then not feeding should not be a reason for panic. It is always nice, however, to get them feeding if you can, but resorting to force feeding should only be done if the snake is losing weight. If the babies are feeding, you may want to not hibernate them during their first winter, using that time to feed them weekly and ensure them a good, healthy start in life.

Young rosys will have almost attained their full adult size by their second winter. Sexual maturity occurs by age 3-4 years. Females in the wild generally breed only every other year, though this may not be the case in captivity. If you do breed yearly, be sure to evaluate the female's overall condition individually each year before doing so. If she is not up to breeding weight or has not fully recovered from the previous fall's birthing, let her rest a year.

Sources

Mattison, C. The Care of Reptiles and Amphibians in Captivity. London: Blandford Press. 1982/1992

Walls, J. G. Boas: Rosy and Ground. Neptune City NJ: TFH Publications. 1994

Obst, F. J., et al. The Completely Illustrated Atlas of Reptiles and Amphibians for the Terrarium. Neptune City NJ: TFH Publications. 1988