Melinda's Red Tail Boa Constrictor Page
A source for information on the care and well being of the Columbian Red Tail Boa Constrictor.
INTRODUCTION The Boa Constrictor has recieved a bad press. The fact is that they actually make great and very impressive pets. The name conjures up, for many, the image of a huge, dangerous, unpredictable, savage, implacable enemy of man. That is at least the image that much of the media would have us believe. The fact is that almost nothing could be farther from the truth. Boa Constrictors are not especially large compared to other large snakes like Burmese Pythons, Anacondas, or Reticulated Pythons. They are the medium sized species of the world's largest snakes. They are certainly not dangerous, if sensibly handled, are in most circumstances very predicable, and have no inclination to be aggresive, other than in self defence. In short, they are far less dangerous to man than the average pet dog. Every year several people are killed, or serouisly hurt, by pet dogs. There are no documented cases, in the U.K., of anyone having been killed by a Boa Constrictor. With proper care they are beautiful, responsive animals that are a privilege to own. The Boa Constrictor is one of the most attrictive, as well as one of the most intelligent of snakes. When kindly treated and frequently handled, it often becomes quite tame, and may even show what is interpreted by its owner as a certain degree of affection. However, potential owners must beware that the baby boa of approximately 45cm long (18"), as normally purchased from a dealer, will potentially grow into an 2.5 meter (8'3")adult weighing approximately 25kg (55lb). It will probably start on mice and end up requiring large rats and rabbits, and a consequently much larger vivarium to house it in.
WHAT'S IN A NAME? The name Boa Constrictor is also, perhaps unsurprisingly, its scientific name, though this is rarely the case with other reptile species. The scientific name of any species is normally writing in italics-i.e. Boa Constrictor. Scientific names are important to establish exactly which species or sub species we are discussing. Common names for species, and may not be familiar in other countries or ages.In Victorian times, in the U.K., the Boa Constrictor was sometimes known as the King Snake or Harlequin Snake, though more commonly referred to as the Common Boa. In Brazil it is called Giboia or Jiboia, Botocudo by the Indians of the Minas Gerais boundary. In Triniddad it is called the macajuel, and on St.Vincent, the Tete-chien. In Argentina it is called Boa de las Vizcacheras, on account of its frequently being found in the burrows of Viscachas, a type of rodent. In other parts of its range it is called Boa Constrictora, Lampalagua, Tragavenados, Macaurel, Mazacuata and Vibora Sorda. Therefore, it should now be clear why herpetologists usually use the scientific name when talking about a species, so that there can be no confusion.Unfortunately the taxonomy or classification, of the Boa Constrictor and its sub species in a poor state.This is all the more surprising given the popularity of these snakes, both as pets and in zoological collections. The history of the classification of this species comprises a series of unrelated descriptions of sub-species from various locations, with little or no correlation between geographic areas, or previously described sub-species. Frankly it is a mess, and our scientific community is long overdue to conduct a thorough overhaul on it. This is not assisted by the fact that even local populations can be highly variable in both colour and pattern, let alone geographically disparte populations.
RECORD LENGTH, FACT OR FICTION? In 1894 the Rev.Gregory C. Bateman stated in his book, "The Vivarium," that "The Common Boa is a native of tropical South America, and it is found from Venezuela to Buenos Aires. It hardly ever reaches a greater length than 12ft (3.66 meters)". This is probably still an accurate assessment of normal maximum size.
LONGEVITY- As we become more adept at keeping reptile species in captivity, longevities will undoubtedly surpass many of those records that have been previously established. However it is probably unlikely that the record will be exceeded by much, compared to that of the Boa Constrictor kept, for the latter part of its life, at the Philadelphia Zoo. Originally in the possession of Eugenia S. Shorrock, of Reading, Massachusetts, for its first 33 years of life, this animal lived for a total of 40 years 3 months and 14 days. This is believed to be the longest lived of any snake species ever kept in captivity, to date. This animal was only about 1.8 meters long (6ft), and was therefore relately small compared to many captive Boa constrictors. This old, but small adult Boa poses interesting questions. Empirical evidence therefore suggests that poorly fed Boas will live much longer than those that are continually fed to appetite. This same result is well documented in rats, for example. those that are fed ad libitum. So this Boa's probable poor appetite whilst in captivity could be the reason why it achieved such a great age.
LOCOMOTION-Generally snakes exhibit four types of specialist locomotion, lateral undulations of the body, which is the typical serpentine motion, retilinear or caterpillar movement, sidewinding, and concertina type movements. Boa Constrictors normally employ the first two types of progression. The classic serpentine motion is probably well known, and therefore requires no description. It is used by Boas to progress quickly when alarmed, and seeking escape, or when chasing prey. The second type of locomotion, rectilinear or caterpillar, is normally seen only frequently employed by the larger snakes. The motion is a slow, deliberate, forward progression with little or no lateral movement, the snakes body being orientated in a more or less straight line in the direction of travel. The snake appears to be walking on its ribs, though this is actually not the case. The ribs in themselves do not actually move. It is the muscles attached to the ribs which raise the ventral plates in sections, carry them forward slightly, and then replace them onto the ground, to gain traction for the subsequent forward movement. Boas engaged in rectilinear motion can usually be interpreted as being comfortable and relaxed with their current situation, and can usually be handled with confidence at this time.
CHOOSING YOUR BOA CONSTRICTOR-The proper selection of your Boa constrictor is vital for your long term success and satisfaction in keeping the animal, particularly if choosing a newborn specimen.First check the health of the animal. Look for those indivduals which have a firm fleshed, rounded body shape, with no evidence of pronounced rib or backbone protrusion. Young animals should be scale perfect, with no visible skin burns or other injuries. When they are active they should be interested and inquisitive about their surroundings, accompanied by regular tongue flicking, testing their environment.Unhealthly Boas tongue flick halh heartedly, the tongue may only be protruding slightly, and at infrequent intervals. they don't move very much either. These animals may be suffering from respiratory disease, which may be further indicated by bubbly mucous from the mouth and nostrils, plus labored breathng. A recently fed animal may also be less active, but may be indicated by a positive bulge in the body; between a half and two thirds of the length of the animal. If recently fed, subsequent transportation and a probable consequential drop in temperture, may lead to regurgitation. When handled, the snake should be active and mobile. It is important not to restrict its movements too much, just enough gentle restraint to retain control. The snake should feel powerful for its size, and firm, with good muscle tone. Reject those animals that feel limp and flacid. Check the head and mouth; the tongue should be flicking actively. Both eyes should be clear and healthy unles clouded over indicating an imminent slough. If only one eye is cloudy this could indicate retained eyecaps from prevous sloths and or infection. There should be no abrasions on the nose that could lead to secondary bacterial infections. The month should close neatly with no sign of swelling or mucous emerging from the sides (signs of mouth infections and respiratory disease). If the snake will open its mouth or you are able to genty pull down a lower lip, look for cheesy looking pus and /or red, raw looking areas, all of which are indicators of mouthrot (necrotic stommatitis). Listen to the breathing. It should be hardly discernible. Any whistling or bubbling is a bad sign. gentle pressure on the throat region may cause mucous to emerge from the sides of the mouth and the nostrils, again signs of respiratory infection, usually caused by the animals being maintained at suboptimal temperatures. Now look at the body of the snake. There should be no lumps other than indications of having recently fed, or depressions along the sides, indicating broken ribs. The spinal area should be well fleshed and free from kinks and lumps. Finally look on the body for mites. These are only the size of specks of dust but may be seen moving over the body, if present, by those with keen eyesite. They look like tiny reddish brown beads. Additionally if mites are present the snake may have a dusty appearance which is caused by white faeces of the mites. Mites can also be seen embedded around the eye giving it a raised and swollen appearance. After handling, mites may be more visible moving around on your hands. Similarly mites are more easily visible on lighter coloured and albino Boas. They are highly host specific so they won't harm you but you could easily transfer them to another reptile.Look at the under side of the snake. Those that have been kept on wet substrates will often exhibit areas of scale rot. These will look like brown staining, particularly on the edge of the ventral scales. What you see may indicate a much larger area of infection in the body cavity, usually in the form of an abcess. Also look for other early signs such as rasied or damaged scales, and hard areas that are palpable. finally look at the cloaca, that area where the single belly scales (ventrals) suddenly give way to the under scaling of the tail (subcaudals). This area should be clean and free from faeces. there should certainly be no noticeable swelling or gaping of the cloaca.
SEXING YOUR BOAS Sexing these species of snakes is possible by superficial observation.Mature males are usually smaller, and have larger spurs, either side of the cloaca.
More sophisticated techniques of sexing include using specially designed blunt ended, lubricated metal sexing probes. These are carefully selected for size to suit the size of snake to be sexed, about 1mm-2.5mm diameter for mature Boa Constrictors, 0.5mm for babies.The lubricated probe is gently inserted into the snakes cloaca, towards the tail, and to one side or the other, never centrally. When the probe is withdrawn, the depth can be marked with a fingernail placed on the probe, adjacent to its entrance into the cloaca. The withdrawn probe is then laid along the outside of the tail, and its depth compared to the number of subcaudal scales it covers. If the probe penetrates easily for a depth of 10-12 subcaudal scales, this indicates a male. The probe is then lying within the hollow tube in the centre of one of the inverted hemipenes. male snakes have two of these intromittent organs, rather like the inverted fingers of a rubber glove. These lie side by side in the base of the tail and lead to its thicker apperance that that of a female. Mature female Boas will only probe to a depth of 2-4 subcaudal scales. This technique is best left to experienced herpetologists as the potential to cause damage should be apparent. Another expert's technique, reserved for baby snakes, is to manually evert the hemipenes by applying a rolling pressure from well down the tail towards the cloaca. This works only on baby snakes because their muscular control of the hemipenes is not well developed. Everted hemipenes indiacate a male, whilst a female is indicated by two small red dots, which are the entrance to the musk glands.
ACCOMMODATION AND THE CAPTIVE ENVIRONMENT The size of the vivarium that you select is dependent upon how many individual snakes you wish to keep,and whether you choose to house them individually or communally. Boas are generally best housed individually, as they are then easier to manage and feed. The dimensions of the vivarium to house these species is not especially critical. However, a good rule of thumb is that the vivariums combined dimensions of width and length should be at least two thirds the length of the maximum of approximately 2 meters (6ft 6in) for fully grown Boas. cage dimensions below these recommendations will obviously be suitable only for smaller specimens. the height of the container should be at least 60cm (2ft) or more, both to accommodate a heat source effectively, and provide space for strong branches for climbing. Boas are, to some extent arboreal, and are frequently found in trees in the wild, though they are just as frequently found at ground level, and even in burrows.The type of container chosen to house your snakes will depend upon the specimens size. Babies can be housed in any proprietary type of vivarium, but adults, because of their size, usually require a unit built for the purpose, constructed of melamine-faced chipboard or wood.Aquariums are waterproof, easy to clean and disinfect, and offer good all round visibilty. They will require the addition of a readily available metal vivarium lid made for the purpose, which incorporates a ventilation strip, a glass sliding lid for access, and predrilled eletric light bulb opening to provide both heat and light, which should be thermostatically controlled. Bear in mind that the average centrally heated room can vary in temperature throughout the year by as much as 20 degrees C (50 degree f); hence the requirement always for thermostatic control of vivarium heat sources. The security of the lid can be improved by taping it to the aquarium at the sides. this is prticularly important for Boas, which are larger and stronger than many other species, and may under some circumstances prise these lids off and escape. All snakes are great escape artists, so care must be taken to ensure that there are no loose parts or small gaps where a snake could conceivably contrive an exit. Simply relying on the placing of a heavy object like a brick on the lids is not a good idea!
Aquariums do not, however hold heat well, particularly substrate temperature, so if placed in a cold room will need to be lagged on three sides with good insulating material. An attractive option is to attach cork tiles to the outside walls, thereby retaining the ease of internal cleaning. Overhead heat sources such as light bulbs may heat the air to the desired temperature but as glass is a poor heat retainer the floor will always be cooler. Supplementary floor heating is therefore a particularly important consideration for Boas. bear in mind that glass tanks placed in a sunny spot within the room may well heat up to alarming levels with consequent disatrous results for the inmates, so locate carefully.Additional disadvantages of aquariums are that they are heavy, break easily and dangerously, and can only be ventilated from the top. Top ventilation allows heat to escape easily while retaining heavier than air waste gases such as carbon dioxide at the bottom where the snakes will spend most of their time. Most of these disadvantages can be minimised by sensible pratice and good hygiene.Plastic box cages, designed for small animals of several categories, are available from a number of different manufacturers. Some of these are ideal only for smaller Boas. Essentially all are clear, rigid plastic boxes with or without some side ventilation slots. All have a well ventilated, plasticlid which clips into place, and, usually, with the provision of one or two small sometimes lockable openable clear rigid plastic access windows. Remember how easily strong little Boas can prise lids off? Ensure absolute security and modify if necessary.These plastic box cages are available in a range of up to six sizes ranging from approximately 18cm x 11cm x 13cm high (7" x 4.3" x 5") to 45cm x 30cm x 18cm high (17.7" x 11.8" 7"). The medium to larger sizes are useful for temporarily holding small Boas during main cage cleaning and transporting. The largest size is just about large enough to house one to two younger Boas, up to say 60cm (2ft) long. Vivariums manufactured from melamine coated chipboard are available in an infinite number of sizes colours and designs. The simplest are basically wooden boxes fitted with two sliding glass doors and a ventilation panel at the top of the rear panel. For adult Boas the glass should be of at least 6mm (1/4") thick, and preferably toughened or laminated. These doors can be secured by a small rubber wedge (not recommended for Boas) a judiciously designed bent piece of rigid wire or a glass showcase lock (recommended method) for total security particularly where small children are present.
VIVARIUM SUBSTRATES Some kind of floor covering makes cleaning easier. Paper (including newspaper), outdoor carpet, and pea gravel are good. Shredded aspen, a fibrous wood product, is also good for medium and large snakes. Sand, soil, sawdust, and kitty litter are not good. Sand and soil don't dry well, and a wet cage encourages skin diseases. Dust from sawdust or kitty litter can give a snake incurable pneumonia. Cedar chips may also be toxic.
TEMPERATURE REQIREMENTS The provision of heating for your snakes is essential for most of the year. In addition it is best provided in the form of a thermal gradient, and with a reasonable air temperature throughout the vivarium. That is to say that the surface temperature at one end of the cage should be set at the snakes optimum requirment (30-35C/88-95F), slightly cooler surface temperature conditions at the oppisite end, and an overall air temperature of (28-30C/82-86F). Baby Boas frequently thrive better at the higher temperatures indicated above. This regime enables the snake to thermoregulate effectely, i.e, find its optimum temperature within the range offered, whenever it chooses to do so, by basking at the hot end or cooling off at the other. Boa Constrictors are not as effective thermoregulators as temperate species of snake, so careful observation must be made to ensure that they are not always at the cooler end of their cage. Nighttime temperatures can be allowed to drop to 24-27 c/75-80F. Surface temperatures below 21C/70F for any length of time, and associated cool air temperatures, are dangerous, and may lead to rspiratory infection, regurgitation of undigested food, and susceptibility to other diseases, such as mouth rot (necrotic stomatis)> The temperatures of water provided should be at least the same as the air temperature to prevent thermal shock, if the animal chooses to bathe. This is particulary important for baby boas which will suffer from chills more readly than adults. Because the temperature even in a centrally heated room can vary by as much as 20C/50F throughout the year, a constant heat source applied in this highly variable situation will clearly not give the consistent results required. Thermostatic control is always essential.
SKIN SHEDDING Every one to three months a snake sheds its skin. The eye is cloudy for a few days, then clears, and the skin is shed a few days later. Shedding takes only a few minutes, once the old skin is rubbed loose at the lips. Most snakes refuse food during this period. Sometimes not all of the skin is shed. This seldom happens if the humidity is kept at the proper level of 40 to 70 percent. Daily spraying with water after the eyes clear helps to prevent problems. If some of the skin remains unshed, the snake should be soaked in a container half full of water at 70 to 85 degrees F for an hour or so. Then the old skin can be gently peeled off.
PARASITES AND DISEASESnakes can suffer from many ailments - mites and ticks on the skin, worms in the gut, and protozoa, bacteria, or viruses attacking the mouth, skin, and internal organs. Even cancer has been found. New specimens should be quarantined for at least two weeks so that they can be checked for parasites and disease. If the owner is not equipped to treat any diseases that occur, the snake should be taken to a veterinarian who is experienced in treating reptiles. Ticks are arthropods an eighth of an inch long or more that suck blood and carry disease. They can be gently pulled off with forceps and dropped in a vial of alcohol. Try to avoid leaving the head in the snake's skin. Mites are pinhead-sized, blood sucking arthropods closely related to ticks. The common snake mite almost always arrives on a snake from a pet store or other infested location. They are seldom found on freshly caught snakes. Putting a two inch square piece of a Shell No-Pest Strip or equivalent (active ingredient = 2,2-dichlorovinyl dimethyl phosphate) in the snake cage over night kills the mites. Put the Strip in a cardboard or plastic container with holes in it. The insecticide can come out, but the snake can't touch the Strip. Don't give water at this time. Afterwards, clean the cage well. This treatment should be enough if the mite-carrying snake has just arrived. If the mites aren't detected immediately, they spread. The treatment may have to be repeated once a week for a month to catch them all. Worm parasites are often present in the gut where most do little harm. They are detected by fecal examinations and killed with commercial wormers.
FEEDING AND GROWTH In the wild, Boa Constrictors feed on small mammels, birds and lizards. One even found to have eaten a porcupine! Baby Boa Constrictors begin to feed, like most baby snakes, after they have shed their skin for the first time. They will usually start feeding on mice. All prey offered should usually be of a diameter equal or less than the diameter of the snake at mid body. As the snake grows it can be introduced to larger mice, then similarly sizez rats, and ultimately rabbits. All food offered should be pre killed, both for the snakes personal safety and to avoid unwelcome attention of Animal Welfare groups. Whilst it is not strictly speaking against the law to offer live prey to snakes, it is against the law to cause unnecessary suffering to live animals, including prey animals. Wheather a live prey animal did suffer by being offered to a snake would have to be decided at law, and the interpretation would, almost certainly, vary from case to case. For example it could be argued that the snake would be caused unnecessary suffering from starvation, if it could be proved that it would only accept live prey, and that the offered prey did not also unnecessarily suffer as a result of being killed by the snake, and housed with it before being killed. This may mean that the prey animal should have access to food and water whilst housed with the snake prior to being killed, and not left for any length of time with the snake, if it appeared to be uninterested in feeding. In the case of the Boa Constrictors it is very unlikely that an individual will refuse fresh killed prey, and there is, therefore, little reason, or justification, in doing so. Food items offered of a larger size than that indicated above may well be regurgitated a few days after being eaten. This is because the preys body expands in size within the snakes stomach due to gas build up, and becomes uncomfortable for the snake. Only when the digestive juices break through the prey's body wall are these gases released. Slitting the abdomen of larger prey animals often prevents this occurrence, if no smaller prey items are available. It is always best therefore to feed several smaller prey items than one large one, to satisfy your Boa's appetite. Boas that are reluctant to feed can often be tempted with day old chicks, or adult chickens.
Skull of a Boa Constrictor indicating the impressive array of recurved teeth they possess, to effectively grip and restrain struggling prey, and to subsequently pull the prey into the throat.
TEMPERAMENT AND HANDLING Baby Boas initially have a low threshold for defensive behaviour. This is not surprising as in the wild they are small and vunerable. If handled gently and considerately they quickly become tame. Only a relatively few specimens will remain aggressive. However, Argentine Boas, Hoggs Island Boas, and some Red Tail Boas are more likely to remain aggressive. Wild caught adults are always more likely to be unpredictable in this regard than captive raised animals. If you want to keep your Boa tame it is best to handle it frequently, say several times per week. For those more interested in breeding from their animals, unnecessary handling id best avoided.Those Boas that are handled regulary are more likely to move slowly and deliberately in caterpillar fashion. Those that are nervous will move with more rapid typical serpentine movements, with rapid tounge flicking.Bites from baby boas are insignificant, but bites from adult Boas are painful and best avoided. They usually give warning that they are going to bite by rasing and coiling the head and neck into an 'S' shape, may hiss, and usually extend their tounges deliberately and slowly. Sudden movements on your part, within range of the snake, may elicit a bite at this time. Bites are also possible incidently when offering food; the Boa misjudges and bites you instead of the prey. Any prey movement,even if previously ignored, may well precipitate an attack. Therfore be extra vigilant when offering prey and removing uneaten items. the best principle to adopt is the "ten foot barge pole" approach.use long snake feeding forceps to manipulate prey in the presense of the adult Boa. particularly for adult Boas that are infrequently handled, the use of shields when servicing their quarters is advisable. These can be adapted from polythene dustbin lids, or constructed from clear acrylic plastic, for better vision. Dustbin lids can also be placed over Boas to temporarily isolate them, and prior to picking them up. You can also place towels over their heads. Either of these procedures is advisable as the highest risk period is when you actually go to pick up the animal from its vivarium. Once in the hand most Boas are docile. The reason for this is likelybecause the Boa associates having its vivarium door opened with the appearence of food, so its principle is probably, "if it moves, grab it and see if it is edible". Snake hooks can also be intelligently used to manipulate the boa partly out of its cage before touching it by hand, or completely moved remotely by handling with two hooks for cage transference, etc. It should be common sense that large Boas should never be allowed to wrap around your neck, or indeed come anywhere within striking distance of your face. Supported at several points along the body, tame boas should only need gentle control to redirect their movements whilst being handled.
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