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Introduction

The Rosy Boa (Lichanura trivirgata) has recently become one of the more popular reptiles to own and keep in captivity. The reasons for the Rosy Boa’s popularity are numerous and well merited. They are docile, slow moving snakes which seldom bite, are represented by a wide spectrum of interesting colors and stripe patterns, and are generally easy to maintain and propagate. This care sheet will outline successful strategies for maintaining rosy boas based upon experience with L. trivirgata ssp. from many different geographic localities.

Captive Care

The most important principles in maintaining healthy rosy boas is access to a proper thermal gradient and low enclosure humidity. Thermoregulation is necessary for proper digestion and gestation. Rosy boas inhabit hot, arid environments with high sun exposure. Such climatic conditions have enabled the Rosy Boa to utilize its adaptive traits of nocturnal behavior, low metabolic rate, and heat sensing predatory capabilities (common to most boas). They are predominately found associated with granitic rock outcroppings and sparse vegetation. Such an environment gives Lichanura high sun exposure while concealing itself, as well as creating a natural thermal gradient.

Enclosure Set-Up. Many different types of enclosures will work, e.g. glass aquariums or plastic sweater boxes, with proper thermal gradient and excellent ventilation the most critical elements. Use of an undertank heating pad or hot rock is one of the more effective ways to achieve a thermal gradient, particularly when using a thermostat controller. Surface temperatures should provide the following thermal gradient: cooler side 78^o-80^oF<--->87^o-90^oF warmer side

Heat of this kind is much more preferable than use of a light. Lights rarely add value to maintaining healthy rosy boas and primarily serve to enhance the aesthetic qualities of the enclosure. Too much heat, or too little, can result in regurgitation, which often leads to more serious health consequences.

The size of the enclosure should be matched to the size of the boa. For adults, the equivalent a 10 gallon aquarium sized enclosure is usually large enough (base of 200 sq. inches or more), but a larger enclosure may be desirable for boas exceeding 32 inches. The surface area of the cage floor is more relevant than cage height. The enclosure and ground substrate should stay as dry as possible, and excellent ventilation will help maintain low humidity, thus screen tops are preferred. The optimal enclosure substrate is a matter of preference. Several are recommended, including Aspen bedding, Carefresh, pine shavings (but not cedar), sand or sterilized granitic soil, shredded paper or newspaper. All of these substrates are more or less dehydrated and highly absorbent. Provide enough base substrate (1"-2") to prevent the animal from burning itself by direct contact with the heat source. Some rosy boas can become stressed without a hide box, resulting in non-feeding or regurgitation. Either provide a hide box or use a substrate which permits burrowing, as rosy boas enjoy excavating and hiding. Your boa may also utilize a branch or small rock pile for climbing.

Feeding and Water. Rosy boas predominately prey on rodents, and in captivity, this is almost exclusively the case. Feeding rosy boas properly sized mice at the right intervals is also critical to their health. The following table provides some basic guidance. Remember that larger or more frequent meals will require greater energy (heat) from your Rosy Boa to adequately digest.

Rosy Boa Size	Prey Item(s)	How Often
Neonate	pinkie or young fuzzy mice	Every 3-4 days
Juvenile	fuzzy mice or pinkie rats	Every 4-5 days
Subadult	fuzzy or hopper mice, or pinkie rats	Every 4-7 days
Adult	small adult or hopper mice, or fuzzy rats	Weekly
Large Adult	adult mice or subadult rats	Every 7-14 days

Some of the frequent causes of non-feeding boas is stress, suboptimal thermal gradient, or overhandling. If your Rosy Boa repeatedly refuses food, try using a hide box, offer smaller sized prey in the early evening, offer thoroughly thawed frozen mice, reduce handling, and/or provide a more natural environment. Neonates may often prefer thawed frozen pinkies and runt hoppers. Adult males will often discontinue feeding while breeding season is ongoing, and females may discontinue while gravid. Both situations are normal and not cause for alarm. After breeding, or delivery of a litter, rosy boas usually return to normal feeding regimens. Seasonal change can also affect appetite, and the onset of Fall may trigger the Rosy Boa, particularly neonates, to stop feeding and prepare for winter. If this is observed, withhold food for two weeks, then cool the animal to 50^o-64^oF for 3-10 weeks. Upon warming to normal temperatures, most rosy boas will resume feeding.

Water is offered sparingly. For adults, place a small water dish in the enclosure for 1 day every 2-4 weeks, or 1 day every 2-3 weeks for neonates and juveniles.  Alternatively, a partially covered, shallow water dish may be left in the cool side of the enclosure at all times.  Unlike husbandry of many other species of snakes, the water provided should be shallow enough to prevent the animal from emersing or soaking itself. Water dishes should also be removed to avoid increasing enclosure humidity.

Propagation

The Rosy Boa is rewarding to both keep and propagate. Techniques and know how on captive breeding was first developed in the mid-1970s, refined in the 1980s, and commercially pursued in the 1990s. Selective breeding has produced many outstanding examples of color and can be employed to enhance various physical attributes of interest.

There are three important keys to successfully breeding your Rosy Boa: i) using adults of adequate size and health, ii) winter "cooling" known as brumation, and iii) proper feeding before and after brumation. Breeding pairs should be at least past their second winter (approximately 20 months old) but preferably 3 or more years of age. Size is also important, with a length > 26 inches another useful criterion.

Prior to brumation, rosy boas need to accumulate as much fat stores as possible through frequent feedings. This will provide the animal with a source of energy during the winter period and may potentially influence the number of ova (thus offspring) produced. In preparing for brumation, the breeding pair of rosy boas should discontinue feeding for 2 weeks prior to cooling, then be cooled to a temperature of 55^o-65^oF for 12 weeks. Brumation is usually coordinated with seasonal change and is best initiated in November and terminated in late-February.  During the brumation period water should be offered at least once. Brumation is simply ended by returning the breeding pair to its regular enclosure temperature as previously discussed. Resume feeding 3-5 days after reheating by starting with one small size mouse and building up over 2-3 weeks. In contrast to some other published information on breeding rosy boas, do not feed the animal as much as it wants immediately after brumation since doing so may result in regurgitation.

Mating occurs 3 weeks to 3 months after brumation depending on the Rosy Boa locality type. Baja and Mexican Rosy Boas typically breed 3-8 weeks after brumation, California and Arizona localities later. Consider the seasonality of the rosy boa’s specific geography as a guideline. Introduce the female to the male’s enclosure several times per week for 12-24 hours each time, or keep them housed together, during breeding season. This will improve chances of successful and complete mating, reducing the likelihood of infertile ova. When mating, the male will climb onto the female, rubbing her body in an effort to interest her. The actual copulation is usually over in less than an hour from onset. The male often stops feeding during breeding season.

A gravid, or pregnant, female can be determined in about 3-4 weeks following a successful mating as the posterior half of the animal increases in girth. Once gravid for 2-3 weeks the female will move directly onto a warmer heat source and the warm side of the thermal gradient should be 90^oF. Birth of live young from clear sacs (ovaviviparous) can be expected 120-140 days following the successful mating. The expecting female will usually move off the heat source 1-3 weeks before delivery and may become more active.

Neonate rosy boas should be separated. They will shed 7-14 days after birth and feeding typically begins at that time. Care and feeding has been covered previously. You may need to encourage a feeding response by gently "tapping" a pinkie mouse to the nose of the neonate. Once feeding, young rosy boas usually develop a voracious appetite.