Husbandry And Propagation

The Basics

The two most important attributes to maintaining captive Rosy Boas are proper enclosure ventilation and the ability to thermoregulate. Proper ventilation is very important in terms of enclosure humidity. Historically, Rosy Boas kept for long periods of time in an enclosure with high humidity experience multiple health issues. The most commonly observed issues are respiratory infection and regurgitation. The ability to thermoregulate is necessary for proper gestation and digestion.

Enclosure Set-Up

Today, many different types of enclosures are used to maintain captive Rosys. To maintain low humidity and a good thermo gradient, I recommend using a glass terrarium with a screen top. All-Glass Aquarium ( manufactures these enclosures. I like them, because they have a sliding top with a locking mechanism. To create a thermo gradient, I run Flexwatt heat tape ( under the back 1/3 of my enclosures. This is then thermostatically controlled. I also use an inverted ceramic pot as a hide spot over the area containing the heat tape. This provides a secure hiding spot for gravid (pregnant) females to gestate their young; The cooler end of the enclosure contains the water bowl and is at ambient room temperature. The following temperatures should provide sufficient thermal gradient: (cool side 70o-80oF, warm side 90o-95oF). Sub-terrain heating sources such as heating pads ( work great too. NEVER use heat rocks. I have seen animals with severe burns and even fatalities from heat rocks. Enclosure substrate is a matter of personal preference. I recommend aspen bedding, pine shavings, and Carefresh. All of these substrates are highly absorbent. NEVER use cedar shavings. I use pine shavings, because it’s economical and easy for the rosys to burrow in if they desire. I suggest a depth of two inches. Provide a hide box or use a substrate which permits burrowing. As mentioned before, I use an inverted ceramic pot. They are economical as well as easy to wash.

Feeding and Water

As captives, Rosy Boas almost exclusively feed on rodents. Frequency and size of their food is critical to their well being. I recommend using the following as a basic “rule of thumb”. Small food items fed more frequent are the best practice.

Animal Age Food Item Frequency
Neonate 1 pinkie mouse or small fuzzy mouse Every 3-4 days
Juvenile (1 yr) 2 fuzzy mice or pinkie rats Every 4-5 days
Subadult (2-3 yrs) 2 large fuzzy mice, small hopper mice, or pinkie rats Every 4-5 days
Adult (3-6 yrs) 2 adult mice, or fuzzy rats Every 4-5 days
Large Adult (6-10 yrs) 3 large adult mice, or 2 subadult rats Every 5-7 days

I suggest placing a sturdy water bowl of fresh water in the enclosure once a week. Take the water bowl out before feeding, and do not place it back in the enclosure for 2 days after feeding. Some Rosys will drink a lot of water directly after eating, causing them to regurgitate.

Some of the commonly observed causes for non-feeding boas are poor husbandry (i.e. cleanliness), lack of thermal gradient, and stress (i.e. over handling, multiple cage mates, no hiding spot, and inconsistency of a water supply). Newborn neonates may often refuse food items until after hibernation. Adult males will often decrease and even stop feeding during breeding. Adult females may decrease and even stop feeding while gravid. Once breeding season is over, or delivery of a litter is complete, Rosys readily return to normal feeding. Barometric changes, seasonal change, and a reduced photo period can also affect appetite.


The techniques of Rosy Boa captive breeding were first pioneered in the early 70’s, improved upon in the 80’s, and refined through the 90’s. As I mentioned before, I have been mentored by one of these pioneers, and practicing these methods that have led to the success I achieve when breeding my Rosys today. In my opinion, the most important attributes to my success is only using animals of 3 + years of age, with adequate weight, observing a winter cooling period (i.e. hibernation), and the consistent long length of time mates are kept together. Animals not meeting these basic criteria are not used as it may potentially manipulate the number of ova, and sperm produced. Preparing for hibernation is simple. Animals should discontinue feeding for 2 weeks prior to cooling, giving them enough time to defecate all fecal matter, as it will poison them from the inside out at low temperatures. Slowly cool them to a temperature of 50o-55o for 12 weeks. Hibernation is usually best initiated the first of November, ending the first of February. During hibernation, water should be offered once every 4 weeks. Ending the hibernation period is simple too. Slowly return the animals to an ambient room temperature of 70o and slowly increase the temperature of your heat source to 90o-95o over the course of a week. Begin feeding 3-5 days after completing the re-heating process, using a small size mouse, increasing the size and quantity over the next 2-3 weeks. Do not feed the animals as much as they want immediately after hibernation, as it may cause in regurgitation.

Breeding generally occurs 1-3 months after hibernation. Geographic origin creates the variable in time frame during this period. Baja California and mainland Mexico localities usually are the first to breed, then the low elevation desert localities, then the coastal localities, and finally the high elevation localities. Introduce the male to the female’s enclosure beginning in April, only removing him to feed, and keeping him with the female through June. This will increase chances of a successful and complete breeding, reducing the potential of infertile ova, by not missing any window of opportunity. In my opinion, putting the male in the female’s enclosure is more successful, because females may be producing pheromones, signaling the male that she is ready to breed. Again, just my opinion. While breeding, the male will climb onto the female, rubbing her body and “spurring” her with his spurs to stimulate her in to submit to copulation. Copulation can last for minutes or hours. Males can be used on several females successfully.

When female’s become gravid (3-4 weeks following a successful copulation) the posterior half of the animal increases in girth. Once gravid, she will move directly onto the heat source, with the warm side of the thermal gradient consistently at 90o -95o. Expecting female’s will usually move off the heat source 1-2 weeks before delivery and may become more active. It almost seems as though are looking for the proper place to give birth. Rosys are ovoviviparous, giving birth to live young contained in a sort of clear sac in about 130 days. I have had neonates get stuck inside the sac and perish. I have physically removed several from the sac by hand. Resume feeding her 3-4 days (starting with a small food item) after she has given birth.

Neonate (baby) Rosy Boas should be separated no longer than 12 hours post delivery. They will then shed 1-2 weeks after birth. You can try feeding them prior to their first shed, but post shed feeding is usually more successful. Use the above rule of thumb method when feeding. I also put the neonates separately in to deli cups when feeding. I also do this at night so that I can turn of the light to offer more security. Encouragement is sometimes required to create a feeding response. You can very gently tap the nose of the neonate with the pinkie mouse, stimulating a strike. They don’t always grab the pinkie. Persist for only a couple of minutes. If it shies away consistently, try again the next night. Once they start feeding, neonate captive born Rosys become voracious feeders. Newcomers to Rosy Boas often mistake this behavior as aggression.