Boa Constrictors can be bred in captivity by following a number of simple but essential steps.
Putting together your breeding group is the first step. Sexual maturity in boas is typically reached at 18 months for males and 30 months for females. Similar to other snakes it is good practice to start males breeding in their third winter and females in their forth. As a general rule, males should be about 4feet long and females 6 feet, and both should also exhibit good muscle tone.
The ability to correctly sex a boa is an important factor for any boa breeder. Although this task may seem daunting to the novice, with care and practice it is possible to reliably and quickly sex a boa. The two most reliable methods of sexing are popping and probing. When popping a boa constrictor you are trying to evert the hemipenes of the male or the musk glands of a female in order to determine the sex. This procedure can cause severe damage if done incorrectly, so we strongly recommend having an experienced breeder show you how to do this before you attempt it yourself. The process involves a rolling / pushing motion where your thumb is used to evert the sex organs of the snake from the cloacal opening. It is a lot easier to do this when the animal is young and has less strength in its tail.
Probing is done by inserting a thin specially made metal probe into the snake’s cloaca in the direction of the tail. The sex of the snake is determined by the depth of which the probe enters. A male boa will typically probe to a depth of 6+ sub caudal scale whereas a female will only probe to a depth of 2-4 sub caudal scales. Again this is a delicate procedure that can harm the snake if done incorrectly. If any pressure is felt, stop applying any pushing movement, it could be that you have a female or that it’s a male that has tensed it muscles and stopped the probe from going the full length of the inverted hemipene. To be on the safe side, withdraw the probe, re lubricate and try the other side.
Your breeder Boa Constrictors should be put through a cooling or cycling period to help stimulate the breeding cycle. Before your Boas enter the cooling period it is crucial that they are in robust health and have no lingering health issues that could flare up under cooler temperatures. During cycling night time temperatures are lowered to the mid to high 70’s (F) with daytime highs of mid to high 80’S (F) we continue to feed both males and females, but feed smaller less frequent meals. All other basic cleaning procedures stay the same.
After roughly 3-4 weeks of the cooling regime, we begin to introduce males into the female’s enclosure. Unlike Ball Pythons, we don’t work off a schedule for introducing and removing the males. Instead we closely watch for signs of courtship from the male and reception from the female. Courting can sometimes happen immediately but can also take several weeks. During courting the male boa will be incessant in his actions, he will ‘scratch’ the females body with his spurs and be in constant contact with her. Once the female is receptive copulation will take place but is not always observed as it is often very difficult to see actual penetration of the hemipene. Once copulation is suspected, there are several tell-tale signs that indicate that the female is gravid. The first sign is an increase in girth; this is the females’ body getting ready for the actual event of ovulation. A gravid boa will usually refuse all feeding attempts, but it is still a good idea to offer a meal perhaps every 2 weeks but ensure that the food is significantly smaller than her usual meal. Once a female is gravid you may also notice a change in her behaviour, she will coil very tightly on the warm side of her enclosure and may in fact not move from this position for a number of days. Once a female has ovulated she enters a shed cycle, this cycle will happen about 15-20 days after ovulation, and this is the best indicator for when to expect your litter of boas. It is important to record all significant dates, such as ovulation and her post ovulation shed (POS). The average amount of days to pass from her POS and the birth date is 105 days.
About 3-4 days before your Boa gives birth, her activity levels can increase dramatically. She will also look a lot thinner than expected and will pass a very small urate, which is waxier in appearance than usual.
Next comes the joyous moment - the birth of your baby Boas. The birthing process usually takes place during the night although but can also happen during the day. A large female can have upwards of 50 babies in a litter, although the average is usually closer to 30. This number will be smaller for younger females.
Baby Boas are born in an amniotic sack which they need to break through before they can take their first breath. As soon as babies are seen, it’s best to closely watch the female to see if she is still trying to push more babies out or if she is finished. Once you are confident that the female is finished it is easier to remove her from the enclosure and then work on removing the babies. A female that has just finished giving birth will be tired and a lot easier to move than one that has had time to recuperate and is trying to defend her offspring.
When removing the baby boas we always have a roll of paper towel and a dish of warm water. Each baby is removed individually, wiped with paper towel and moved into a sweater box sized tub. We place multiple boas in such a tub that is lined with damp paper towel. Any baby that has not absorbed its yolk fully is housed individually in a shoe box size container again this is lined with damp paper towel. Babies are kept at 90F and always have fresh water and a hide available. Once babies have had their first shed we then set them up individually. Humidity is very important at this early stage. We offer the Boa its first meal 2-3 days after its first shed; a live fuzzy mouse is left in the container and is usually eaten without hesitation. Some boas will not eat straightaway, and wait for the security of darkness before they eat their first meal. Once a Boa has eaten we will feed again one week later.
Breeding projects are one of the most fascinating and dynamic aspects of Boa Constrictors in captivity today. There is a phenomenal range of colour and pattern morphs, all of which are based on specific genetic traits. Each year more and more people are keeping and breeding Boas, and each year more amazing morphs are created. If you are serious about breeding Boa Constrictors it is important to remember that every baby that enters the world in your care is your responsibility. Enjoy your snakes and the breeding process, keep clear precise records, and above all else, have lots and lots of fun.