Rosy boas do not really hibernate, but do go through a period of reduced activity that corresponds with the winter months in which temperature are below optimum. During this period what little activity the may have is primarily during the day. They do not feed during this period as it is potentially lethal. Being cold-blooded, their metabolism, and thus their ability to digest, is dependant on the environment around them, and at low temperatures, it is likely that the food item with begin to decompose and rot before it is digested, becoming toxic to the snake. But this period of inactivity is an important part of their life cycle and in many individuals is totally unavoidable, and in potential breeders is necessary and desirable. Many boas will not breed, or if they do will not produce offspring if not cooled during the winter months. The following are guidelines for this cooling period;
Boas should be healthy and well fed before the cooling period so they have ample body weight to survive the fast associated with brumation. Food should be withheld from the boas a couple weeks prior to dropping the temperature to ensure proper digestion. Many breeders start this fast in November, with the ensuing cooling beginning at the end of the month. Cooling should take place with the temperature dropping gradually over a few days.
Rosy boas can be cooled from 8-16 weeks depending on the body weight of the snake and temperature they are cooled at. It is recommended that they be cooled to around 55-60° F for approximately 12 weeks, with reduced periods of light corresponding to the shorter winter days or no light at all as they generally spend these months below the surface of the desert. Humidity should still be kept low and fresh water should be offered. With the exception of ensuring the cage is dry and the snake watered, the boas should be left untouched for the length of the brumation period.
At the end of February or beginning of March the temperature and lighting can be returned to normal over the length of a couple days. Feeding can be resumed towards the end of the first week at normal temperatures. Care should be taken to ensure they are not overfed, or fed too large an animal at first. Their metabolism can take some time to adjust.
In preparation for the breeding season, rosy boas should be well fed in the weeks after recovering from their winter inactivity. Females need to gain weight for gestation and the males need to be healthy, as many will not feed for the entirety of the breeding season. After 5-7 weeks of feeding, many boas will start becoming increasingly more active and at this time the female can be introduced to the male in the males enclosure. Some breeders will leave the pairs together for weeks at a time separating them only to offer food, while others feel it best to introduce in 24 hour periods a few times a week. Both methods are often successful and which you should use will depend on how many boas you are breeding and how much attention can be given to the boas during this period. Often, copulation will occur almost immediately, especially after a shed. The entire copulation process takes less than an hour and may be repeated several times in a day. After a few weeks of introducing and reintroducing, feeding becomes the priority once again. Females will start to show a bulge nearly 2/3 down the body 4-6 weeks after successful breeding. They should be fed often and smaller meals than usual. Some breeders recommend nutritional supplements at this point as the young are developing rapidly at this point. If the males stopped feeding during breeding they should now have resumed and can be put on a normal feeding regimen.
Img P.1 Coastal Rosy Boa - L. t. roseofusca
Just a few minutes old this newborn boa rest near the drying membrane he was born in.
Gravid females will carry their young for 18-20 weeks and will spend most of this time on the warmest spot in the enclosure. Heat is extremely important during this time as it provides the proper conditions for the young to fully develop in. Within the final 2 weeks of the term, females with generally stop feeding and start to shed. During this time they will become more active and will spend little time on the heat. 3-7 young are then born. Upon birth the babies must escape a thin membranous sac, at which point they should be removed from the female.
Young should be kept separate, especially after their first shed, at which point they start to feed. Newborn (pinkie) mice should be offered shortly after they have shed. It is not uncommon to have a young rosy that will take a few weeks before it begins to feed. It is a good rule of thumb to not handle non feeding boas and to ensure proper temperature and humidity offering small food items until they begin to feed. In extreme cases, one may place a boa in a paper sack with only the food item in with it overnight. Rosy boas are primarily nocturnal and problem feeders are more apt to eat in the evenings. With a little care and patience, nearly all rosy boas will feed on their own.