The species, Boa Constrictor Constrictor is one of the more commonly kept of the larger snakes, these are sometimes sold as "Red Tailed Boas" and come in a large number of regional variations as well as a number of distinct subspecies B.C. Imperator (Mexican Boa) B.C. Occidentalis (Argentine Boa). There are other, distinct subspecies, but by and large, their care is similar to the basic B.C.C.
Before buying ANY of the subspecies of the Boa family, a prospective buyer should consider the eventual size of the snake. A normal "Red Tail" will grow to the region of 8-10 foot and as thick as a mans mid thigh, when ANY snake reaches these proportions it is capable of killing an adult human and younger specimens will be capable of killing children. The distinction should be made here that the snake is capable of killing, though is in most cases not disposed towards it. This leads nicely to the first section of the care sheet.
By and large, the Boa Constrictor family have a placid temperament and are not renowned for aggressive behavior. Young snakes may be a little snappy, but quickly grow out of this when handled on a regular basis. Once removed from the tank a neonate Boa will be able to be handled easily and although some of the subspecies have a reputation for being biters (the Argentines come to mind) this will probably be the result of wild caught specimens which are understandably rather more aggressive. ANY snake that is nervous, or has been badly treated will bite if it feels threatened, and Boas are no exception, when faced with a Boa you don't know, and who doesn't know you, treat it with circumspection until you are familiar with it. It is a generally agreed principal that the handling any snake over 6 foot should not be undertaken alone for safety reasons, Boas fall into this category. Although Boas have reasonable eyesight, and it is believed they have some colour vision, they principally hunt by smell. For this reason it is imperative that after handling snake food you thoroughly wash your hands before handling your Boa. More people are bitten as a result of SFE's (Stupid feeding errors) than any other reason, and they hurt just as much as if the snake was attacking you!
Boas come from a tropical to subtropical climate and need constant heat or they will die. For a normal maintenance program (as opposed to a breeding program) the temperature in a Boas enclosure should have a day time high (DTH) of the high 80's F and a night time low (NTL) of mid to high 70's.F. This will equate to a DTH of 29C and a NTL of 24C. These temperatures should be considered to be ambient air temperatures, and a warm spot should also be available for the snake to bask on. One of the important requirements for keeping Boas is a temperature gradient within the tank, this means having a warmer end and a cooler end. This allows the snake to regulate its own body temperature by moving within the gradient. To achieve this gradient, either an under floor heat mat or a heat lamp at one end of the tank can be used. Thermostatic controls in conjunction with an accurate thermometer are essential to achieve the correct climate for your snake. Many of the cheap thermometers sold in pet shops for reptile enclosures are of little use, and an accurate digital gauge should be purchased from the likes of Radio Shack or Tandy. It is important that the snake has a broadly correct photo period during the day, that is to say, that the light(s) in the tank is not left on 24 hours a day. Use a timer to give a day/night period roughly corresponding to the season outside. A snake left in constant bright light will become stressed which can manifest itself in many ways from aggression, to not eating, to health problems.
Closely associated with temperatures, is humidity. Boa Constrictors do not require the level of humidity of, say, Epicrates, but if shedding problems are encountered, raising the background humidity may be beneficial. A large water bowl left in a warm tank usually generates enough evaporation to fulfill the requirements of these animals. Boas left in too humid conditions have been known to develop scale rot on their belly scales, though this is usually associated with lack of cleanliness in the substrate as well.
All snakes NEED hides where they can feel secure, Boas are no exception. These can be as simple as cardboard boxes with small entrance holes cut in them which can be discarded when soiled to attractive hollow logs specially made for reptile tanks. The important criteria are that they must be clean, and a fairly close fit for the snake. A small snake in a large hide feels nearly as vulnerable as it would without any hide at all. Have several hides in your tank, at least have one warmer hide and a cooler hide, the snake will spend much of its time in these hides, so keep them clean. A box with only one small entrance isn't the best idea, getting the snake out may prove a problem, cut the base out so the box can be removed easily.
Young Boas seem to enjoy climbing, and a suitably cleaned and sterilised branch or tree stem will be used by the snake. As the Boa gets bigger, finding a suitably strong branch will prove more difficult, but with sufficient space in the tank this will prove an attractive and useful item.
One of the main problems associated with owning large snakes such as Boas is the size of the housing needed when the snake has reached its full size at about 5 years old. A single Boa that has reached its adult size will require about 10 square feet of floor space within its tank as a minimum. This equates to a bare minimum of a 5x2 tank, about 2-3 foot high for a single specimen. A pair of Boas kept together may require a 6x3 tank when full size, this is a substantial piece of furniture. Boas can easily live 25-30 years and this tank will need to be in use for the majority of that time, in a small flat or apartment this would take up a considerable amount of the available floor space.
Large tanks are usually constructed from plywood or chipboard with sliding glass doors at the front. In a large (6 foot) tank, the glass should be either toughened or armoured similar to the type of glass used in shop fronts. An all glass tank is much easier to clean and sterilise, but is very difficult to keep warm in temperate countries. Consider lining the floor of a wooden tank with glass to aid cleaning.
The type of substrate used with Boas is largely a matter of individual choice. With young snakes, it is often best to keep them on newspaper or kitchen towel for the first few months as they tend to defecate regularly and it is easier to keep clean. Personally I use wood shavings (pine) on a newspaper base which I find attractive and cheap. Beech chips and Orchid bark are attractive, but expensive options, many professional breeders use newspaper all the time for it's ease of cleaning, but it is not the most aesthetically pleasing choice. DO NOT use Ceder bark, which is commonly sold for rats, hamsters, mice, etc. It contains oils that are very toxic to snakes and can lead to fatality. I spot clean any urates or feces daily and change the entire substrate every 3 weeks or so, depending on how often it has been soiled. IT IS IMPORTANT NOT TO FEED ON A SUBSTRATE OF WOOD SHAVINGS OR WOOD CHIPS. The snake may ingest some of the wood with the food and the cellulose based wood cannot be digested by the snake and results in an impacted blockage which initially causes constipation, and can eventually kill the snake.
Boa Constrictors will normally feed well on mice and rats, when fully grown, rabbit may be an option if available. Young Boas are usually voracious eaters and can take fuzzy mice straight from birth. As with all snakes, feed prey items (preferably dead, defrosted) that are the same diameter as the largest point of the snakes body. Be sure the food is correctly thawed all the way through, warming the food to body temperature is a good idea if possible. The use of microwaves for this is NOT recommended. Depending on the individual snake, Boas are usually private eaters and prefer to be placed in a dark or opaque container with the food item and left to get on with it, if disturbed they will regularly regurgitate a half eaten meal and subsequently ignore it. Place the snake in a separate, clean container with the food already there and close the lid. Leave the snake in there for 20 minutes or so for an adult, 5-10 minutes for a juvenile. These times are what I have found from personal experience with my own Boas, your individual snakes may vary considerably. Keeping the container reasonably warm is beneficial.
As with all snakes, keep the handling of a Boa after eating to the absolute minimum for 24 hours, apart from the possibility of regurgitation, rough handling after a large meal can damage the snakes digestive tract and may prove fatal.
Force feeding Boas with larger specimens will be all but impossible because of their great strength.
In their book "The Reproductive Husbandry of Pythons & Boas", Ross & Marzec state that "Captive breeding of Red Tailed Boas is generally accomplished by advanced rather than amateur herpetoculturists". (p210) The aforementioned book is certainly one of the best volumes on the breeding of Boas, and should be purchased and read if at all possible. However, there is no reason why a patient, dedicated amateur cannot breed the Red Tailed Boa in the correct conditions. Being tropical snakes IT IS VITAL THAT THEY ARE NOT HIBERNATED OR BRUMATED. When a female Boa is put into a breeding schedule, as opposed to a maintenance schedule, the food intake should increased where possible to the point of being slightly overweight. A gravid Boa may not eat for up to 9 months so adequate reserves of body fat are essential. This should take place over a period of about 6 months, during this period, the temperatures in the tank should be progressively changed to a cycle that has a DTH of 90F (30C) and a NTL of 68F (20C). The start of this temperature cycling should be mid October and reach the full NTL and DTH by early December, the male (whose should be kept separately in similar temperature conditions) should be introduced to the female about the 3rd week in December. Mating should begin and continue through until February, by the 1st week in February the temperature cycling should be reversed progressively so that by the 3rd week in March the DTH is at high 80's F and the NTL back to low 80's (25C). If the female is gravid, she will normally refuse food for the period of the pregnancy. It is EXTREMELY important to keep the temperature in the females tank within the correct range during the period of pregnancy, fluctuations above or below usually result in either severe birth defects, or loss of the young altogether.
The gestation period of the Boa Constrictor is 4-8 months. As mating occurs over a period of time it can be difficult to state precisely when the fertilization took place. Temperature of the gravid female also seems to play some part in the equation so putting exact times on is difficult.
Boas give birth to live young, and litter sizes vary from 6-65, the young are independent from birth and should be separated from the mother as soon as possible, Boas are not usually cannibalistic, but the young can be crushed by the bulk of the female. The young have been known to fight as well. Keep the young in small, separate containers, on paper towels with a supply of water. Change the paper whenever it gets soiled and keep a record of the birth date, sex if known, shed details and feeding record on a piece of paper taped to the top of each container. The young will shed, usually within 10 days or so of birth and will normally eat without any problem after the 1st shed.
Although the care of the family Boa Constrictor is broadly the same, there are several significant differences in the appearance and characteristics in the subspecies. Ross & Marzec argue that ALL the Boas from the Amazon and Orinoco basin are the same subspecies and have regional variations in their markings, calling them after the supposed country of origin is ineffectual as snakes are no respecters of national boundaries, and they may have been collected in a country where it was illegal to do so, and shipped over the border to another where it was. This would render irrelevant any regional naming. It is reasonable to assume that snakes have been carried downstream on floating trees etc. and become interbred with the local specimens.
The Hogg Island Boa, was originally native to an island in the Amazon delta, and is now reputed to be extinct in the wild due to the predation of dogs on Hogg island. This is a smaller breed of Boa, and will only reach 4-6 foot in length. Their colouring is noticeably lighter than a normal B.C.C. and the tail is a peach colour, with a high degree of pink colouring along the flanks and belly. The Argentine Boa (B.C.Occidentalis) is regarded as an endangered species and is on the C.I.T.E.S. appendix 1 list. These snakes should be unavailable as wild caught and in European countries are required to be micro-chipped after they are 1 year old. These snakes have a much darker grey background colouring with black saddles. The tail is a dark mahogany brown.
The Peruvian Boa is also regarded as endangered, and it is illegal to export them from Peru, so should be unobtainable as wild caught. It too has darker colouration than the "normal" Boa with a tail that can be a dark purple on occasions.
The Mexican Boa (B.C.Imperator) has markings similar to the Common Boa but is sometimes reckoned to grow bigger than the standard B.C.C. species. Whilst there is no ban on export of these snakes, they can be regarded as a threatened species if not an endangered one.
Buying your Boa
When buying your first Boa, unless you actually SEE an adult, it is difficult to imagine how BIG they grow. The idea of an eight foot snake doesn't sound too bad until you encounter the sheer bulk of such an animal. For preference, always buy from a breeder, ask to see the parents and get some idea of what you'll end up with. The local herp rescue society may have an adult in that they are trying to find a home for, assuming it doesn't have any other problems with its health or attitude, this may be a viable alternative to getting a juvenile.
All Boas have a slight iridescence on their scales, check for this, loss of scale tone is an early indication of health problems. A well fed Boa is a bulky creature, and is very muscular, loose folds of skin are a sign of either none feeding or that the snake is severely undernourished.
When choosing a Boa, look for an animal that that appears alert, the tongue should be flicking regularly and the snake should have a firm, muscular feel to it. The eyes should be bright and clear, check for signs of incompletely shed skin, checking the eye caps and the tip of the tail in particular. Look for signs of scarring from both rodent attack or thermal scarring from contact with unshielded heat lamps. Both will fade with time, but never seem to totally vanish. As with all snakes, check for mites, tiny blood sucking parasites the size of a pin head. These are not difficult to get rid of, but may indicate a less than scrupulously clean previous housing. The vent should be clean without any apparent soreness and the belly scales should not have brown edges as this MAY be an early indication of scale rot. When picked up a Boa should get a fairly firm grip upon your hand or arm with its tail to steady itself, this is normal and although the snake may relax a little when it becomes used to you, is characteristic of most constrictors. Run your hand firmly down the length of the snakes body, making an "O" with your thumb and index finger feeling for lumps in the body of the Boa, especially towards the tail, this MAY be a sign of constipation. Kinks in the spine can be felt in this manner as well, these are usually a birth defect and are permanent, avoid such animals where possible. A well fed Boa should be strongly muscled along the flanks, but light pressure along the center of the back should be able to feel the spinal chord. A snake that has an area of skin visible between each of the scales over the length of the body is obese, this creates similar problems for snakes as in humans, a stricter feeding regime will be called for if bought.
A healthy Boa Constrictor can easily live 25-30 years and should be considered a long term commitment and bought with this in mind. In return it will gives hours of relaxation and pleasure as well as being a fascinating and exotic creature in your home.
Thanks to Dave Fulton for the care sheet.