Dwarf boa constrictors are sometimes met with skepticism within herpetoculture. Some herpers have a hard time digesting the idea that very small boa constrictors do exist in the wild and that they are also represented in captivity. I find them to be some of the most interesting of boa constrictors and have spent enough years working with them now to boldly proclaim that I know first hand they are very real and also very rewarding captives. They are hardy, highly evolved, low maintenance boa that take up very little room. I have slowly raised them to adulthood and bred them at surprisingly small sizes for a boa constrictor. The boa that I consider dwarf boa are all currently considered B c. imperator by taxonomists. A few comparatively small races of B c. constrictor do exist in captivity. My Venezuela Boa are a good example.
So, what exactly is a “dwarf” boa constrictor?
It seems there is no real solid consensus regarding just where the line is to be drawn regarding precisely what criteria of length, girth and/or weight a race of boa constrictor should typically meet in order to be considered a member of the dwarf boa clan. To truly be a dwarf boa I propose that as adults the females should be to the uneducated an almost shockingly small adult boa while also re-productively active and healthy doing so. If adult females can be correctly raised to be healthy and reproduce at a length of around four feet I do consider them a dwarf boa constrictor.
Vin Russo was the first person I remember using the term mid-dwarf boa and I felt he had provided a much needed new category for those in between boa. Boa from this clan may in some individual cases qualify as dwarf boa while others may grow beyond even classification as “mid dwarf boa”.
Hey now, what about that huge boa my I’ve read or heard about that was supposed to be a so called dwarf boa but grew too large?!!
They do exist within captivity. The six foot long Caulkers Cay or Tarahumara Boa is an example that comes to mind. We have learned a great deal about boa constrictor husbandry over the years. With the dwarf boa though a person must understand the natural habits of these unique tiny boa and adjust their husbandry accordingly. Those “larger than they should be” dwarf boa are likely either the product of incorrect husbandry or of non-natural human selection for large size in captivity. Let me explain that last part. We admire the locality specific dwarf boa in part for their ability to adapt and survive in often stingy micro climates. Part of what makes them intriguing is not only that they are small but by what function that is the case. Some fairly recent research by Dr Scott Boback with the Belize cay boa seems to indicate that these small boa are the result of both a genetic tendency toward being small and also a result of the stingy prey availability within the environment in which they live. It seems that boa can start to change from the norm or evolve quite quickly in captivity or in the wild if their living conditions are changed to a scenario that rewards the survival of faster growing boa that eat more prey and reach larger adult size. We must remember that nature chose those boa that survived according her own wisdom and without our input. It is highly likely that we may nurture and perpetuate those boa in captivity that would not survive or at least not to the the sizes they do in captivity if those same boa were still in the wild and subject to nature’s law. It is upon us as dwarf boa keepers to carefully monitor how we pair breeders and manage our husbandry so that all those traits that make a boa race unique are not lost in captivity including their status as dwarf boa. We carefully do this to insure that future herpetoculturists can know intimately these unique boa. The day is rapidly approaching when some of these wild populations may be drastically reduced or eliminated completely.
How should I feed and maintain my dwarf boa constrictor to make sure it doesn’t grow too large?
Five years of slow growing to sexual maturity is the now the accepted benchmark for correctly raised practically any female boa constrictors that will be put into breeding programs by competent and caring herpetoculturists. This “slow growing” of boa constrictors has not only proven to be a more healthy approach for the boa but also a more rewarding approach for the breeder as a larger number of offspring are produced in time versus quickly using up a female boa that was rushed at a young age at the expense her own health. The dwarf boa may be ready to breed in five years or it may take up to seven in my experience under my care. You may also find yourself at the five year mark with a small female boa and wondering if you should pair her for breeding or not. If she is of adequate weight and perfectly healthy I proceed with pairings regardless of her size. This approach is not without risk so adopt it as your own with the understanding that it may work out poorly. Attempting to put off breeding is also not without risk. So far my boa produce if they are ready and do not if they are not ready without consequence. While it may be more likely with a proven breeder it is possible even with a first season sexually mature female that she ovulates and wastes a lot of energy producing slugs. This can be catastrophic for a female boa and even result in death. If a female boa ovulates, a male should be provided. In my experience females that are not ready simply don’t ovulate and produce offspring so I do feed quite sparingly those boa I know are genetically prone to tolerate breeding at a small size. With all my dwarf boa they are seemingly biennial breeders. They could possibly breed yearly with a higher intake of food under a different husbandry regimen.
We manage food intake two ways, feeding frequency and prey size. In some ways, feeding dwarf boa to correct size is more art than science so the information here is presented as a general guideline, not a certain plan for success for every dwarf boa.
Newborns up to one year old get a small (mid body girth of the boa) meal every 10 to 14 days. This meal will barely make a noticeable lump in the snake once consumed. For that first year I want to get their system used to processing and eliminating meals regularly with little pressure for strong growth. It’s a small but frequent meals feeding schedule. Do not rush or push them with large or frequent meals at this stage! Small and delicate young dwarf boa sometimes do not recover from a regurgitation event brought on by overfeeding.
One to two year old boas stay on the same schedule but prey size is moved up to slightly larger than mid body girth. Toward the end of their second year I gradually increase prey size in preparation for the growth spurt that seems to occur for most dwarf boa at two years old.
From two years old to adult I feed my dwarf boa a prey item that makes a nice size lump at mid body. It’s not large enough to stretch the skin and reveal the skin between the scales or interfere with locomotion but it’s a pretty decent size meal. At this point you have raised your boa long enough that females are probably starting to outgrow males by a small degree for those boa that express sexual dimorphism by growth rate based on gender. I do offer food a bit more frequently to females than to males at this age for those boa races where the females outgrow the males. If there is no difference in size between male and female for a certain race of boa (Belize Boa for example) I feed them both the same. In my opinion two years old is the time to start putting size on these dwarf boa. I feed them as much as three rather large meals per month. Some I only feed two large meals per month
Once they are five years old many of the dwarf boa can be cut back to a single large meal per month for males. If you allow for the winter cooling period these adult boas aren’t even eating 12 meals per year!
At all stages of growth you must monitor your boa and adjust to each individuals needs accordingly. Look at pictures of healthy boa and you will see that fat, round boa start becoming obvious to you. Just google “obese boa constrictor” and you will find plenty of photos. It is not the normal condition for a boa to be round in body shape. When the boa folds back on itself creating a bend there should not be pudgy rolls of fat within the bends in it’s body. While more pronounced in some boa races than others, a tall almost squarish body shape is correct. Loose sagging skin is a sign that food intake needs to be increased.
I do implement seasonality as part of my husbandry routine. I used to cool even baby boas in their first year but I have changed that. Boa from their second year on up get cooled every winter season for three months. I think I should point out that I think seasonality is also a good practice for boa in general, whether they are in a breeding program or not.
Starting sometime in November I stop feeding the boa for two weeks before I begin to manipulate their temperature for the winter cooling period. At the end of this two week period I set a date approximately two weeks in the future at which I plan to be completely switched to the “cooling period” temperatures. Over the coming two weeks I adjust three separate parameters. I make said adjustments every other day. Even for those boa in breeding programs I make no other changes to their maintenance including photoperiod. Other keepers do manipulate photoperiod. Boa will also respond to cues from nature outside the walls of the building they live in even in our hemisphere. This is especially true if natural lighting comes in through windows.
Parameter one is the length of time that the maximum daytime high of 90 degrees is maintained at the basking spot each day. For the majority of the year that schedule is 12 hours of maximum high temperature and 12 hours of a nighttime drop in temperature of 4 degrees down to 86 degrees. Starting on day one of the descent into the winter cooling period I decrease the length of time the daytime high is maintained by half an hour. I make that same adjustment every other day for a total of eight adjustments by one half hour each.
Parameter two is the daytime maximum temperature at the basking spot. The target temperature to which we will be dropping is 84 degrees. Starting on day one of the descent into winter cooling I drop the maximum daytime temperature by one degree. I make the same adjustment every other day for a total of six adjustments to the maximum daytime high temperature.
Parameter 3 is the nighttime minimum temperature. Our target low is 68 degrees. Starting on day one of the descent into the winter cooling period I adjust the night time low down by two degrees. I make this same adjustment every other day for a total of nine total adjustments to the nighttime low temperature at the basking spot.
To prepare for the warm up in the spring I simply reverse the entire process. The total length of time I leave my boas in winter cooling mode is approximately 90 days including the two week descent into the winter cooling regimen and the two week ascent back to the normal maintenance regimen.
Some people feed their boa during the winter cool down and some do not. I usually offer one or two very small meals at the most during this period. I also tend to prepare for the coming winter cool period by feeding my boas a few extra meals during the two months approaching the winter cool down period. If the boa are of adequate weight and properly prepared for the cooling period an almost magical thing happens and your younger boa will actually grow during the winter cool down.
Can you underfeed a boa constrictor?
Of course you can and it has been done to disastrous consequences. There is a point where where true underfeeding becomes an attempt to stump the growth of a boa constrictor and is detrimental. Dwarf boa are designed by nature to tolerate a stingy food rationing. Does that mean that each and every boa will tolerate such husbandry? It does not. I have watched as keepers attempted to stunt mid dwarf or non dwarf type boa by restricting their food intake. The boa did grow into small adults but sometimes died. Breedings were extremely disappointing and often resulted in the death of a female. Keeping dwarf boa true to form is harmless. Starving boa nature designed to grow large is a tragedy. It’s worth noting though that males in the wild are much smaller than females when it comes to most of the truly large boa constrictors. This is the case with most boa except a few unique races like the Belize boa.
It is extremely important to provide as wide a thermal gradient for your boa constrictors as possible, especially with the dwarf boa. With a hot spot of 88-90 degrees you will usually find your dwarf boa as far from the heat as possible! Gravid females use the heat quite a bit but she will also suddenly seek to get away from the heat for reasons I won’t assume to understand. If a boa has used a lot of energy mating in the case of males or giving birth in the case of females they will eat more and also bask on the heat more. Other than those life activities the boa constrictor is usually doing what he is designed to do and making the very most out of what temperature options are offered for it to survive on so do give them as many choices as you can. This is at it’s core the very allure of the dwarf boa. They have been masterfully designed to survive, even thrive in very specific and stingy micro niches within nature but they need full access to those parameters provided by nature.