Scope
This article is intended to provide requirements for maintaining Bolivian Short-tailed Boa Husbandry in captivity.
The information below is provided given based on our own experiences and opinions.
Synonym
- Boa constrictor amarali (STULL 1932)1
Conservation Status
- CITES Appendix II2
Natural Distribution
- Southeast Bolivia, Southern Brazil, and Northern Paraguay
Description
Bolivian Short-tailed Boas come in a variety of colors and patterns, and captive animals are often selectively bred for different traits. Selectively bred animals often exhibit aberrant patterns, with broken saddles or striped dorsal patterns. Others have extremely peaked dorsal patterns (saddles) or reduced saddles to the point where they appear as dotted markings. The background color of these boas can range from pastel, to very dark grey in appearance.
The southern range Bolivian Boas are often referred to as “Silver-back” Bolivians because of a group of animals that had been imported to the US from the Sao Paolo, Brazil. This group of animals had a silver/grey coloration, which made them instantly popular among boa keepers, and they adopted the “Silver back” name.
Characteristics
Bolivian Boas are short, stout boas compared to their larger counterparts from Guyana, Suriname, and Peru, which often attain lengths of 2.4-2.7 meters (8-9 ft.).
Bolivian males are less than half the size and weight of females. The table below provides an example of average length and weight for Bolivian Boas.
| Type | Length | Weight |
|---|---|---|
| Males | 1.4 – 1.5 meters (4.5-5 ft.) | 1,800-2,000g (3.9 – 4.4 lbs.) |
| Females | 1.5 – 1.8 meters (5-6 ft.) | 4,000-6,800g (8.8 – 15 lbs.) |
Diet
One key item to successful Bolivian Short-tailed Boa Husbandry Bolivian is diet. Boas should be offered frozen thawed rats of appropriate size. Live rodents are not recommended unless necessary, and in our experience, there is no reason for Bolivians not to accept frozen thawed rodents. Furthermore, adults that have been raised on pre-killed or live rodents in general will readily accept frozen thawed.
During the breeding season (December to March in Canada) adults may voluntarily cease feeding. This is natural for adult boas during the winter months, and provided the animals are in good health, keepers should not be concerned.
We offer our neonates and juveniles food year-round. However, juveniles will often refuse food during winter months. If they don’t accept meals offered during the breeding season, we simply wait two weeks and try again.
Our adults are not fed in the winter, as their food cycles for the breeding season, and we cool our animals in the winter months. Animals should not be fed during these cooling periods, as it may cause complications with their digestion, and is unsafe.
The table that summarizes the size of boa to appropriate prey size. Keepers should select a size that is appropriate to their Boa.
| Neonates | Juveniles | Sub-adults | Adults | |
|---|---|---|---|---|
| Size | Pink rats (4-9g) | Weaned Rats (33-49g) | Small/medium rats (50-164g) | Large rats (165-274g) |
Note: Even our large adult males feed on medium rats
Selecting an appropriate prey size is of high importance for Bolivians, as these boas are more successful if raised on a smaller prey as neonates and juveniles. Boa constrictors have a slower metabolism than their smaller counterpart Boa imperator and prefer cooler temperatures. Therefore, feeding too large of a prey item may result in regurgitation.
We suggest that any boa that is over fed or fed too large a prey item under less-than-ideal husbandry conditions is prone to regurgitation, however Bolivians are more sensitive in this matter, greater care should be taken not to feed to large of prey, don’t feed too often, and to pay closer attention to their temperature regime.
We offer a simple piece of advice; don’t overfeed your boa, and always provide adequate heating and temperature for your animal, and they’ll thrive, just as any other boa constrictor.
Selecting an appropriate prey size is an important part of Bolivian Short-tailed Boa Husbandry. With most boas, an effective way to select an appropriate prey size is by using the diameter of the snake itself. Prey size is equal to the diameter of the boa’s widest body region. However, with Bolivians, we don’t necessarily follow this rule, because Bolivians tend to be short stout boas, which are heavier in the mid-section than other Boa constrictor types. Let us give you some examples:
Example 1
Let’s say that you have an adult female Bolivian that’s approximately 5.5 ft. in length and 12 lbs. At the thickest body region, this animal may be equal to the size of a jumbo rat. Does this mean you should feed a 1.7-meter (5.5 ft.) animal a jumbo rat? In our experience, the answer is no. A jumbo rat is too large for this animal, and we find sticking to large rats with a feeding frequency of every 21 days will suffice.
Example 2
Let’s use an example where you have a neonate Bolivian that is only three months old. Neonate Bolivians are born smaller than other Boa constrictors, averaging only 50 grams or so. Therefore, they require smaller prey sizes. Should you use a prey size equivalent to the diameter of the boa? In this case the answer is yes. Why? Because neonate Bolivians need enough nourishment not only to survive, but to gain mass to grow and thrive.
Feeding Frequency
The table below offers a general guide for feeding frequency. Keepers should adjust feeding frequency to meet the needs of their own animals.
| Neonates | Sub-adults | Adults | |
|---|---|---|---|
| Frequency | 7 days | 10-15 days | 30 days |
Hopefully, this comparison makes sense, and you get a better understanding of how to appropriately select a prey size to feed your boa.
Housing
Properly housing Bolivian boas, like all boas, is important. Selecting an appropriate terrarium size and providing the correct temperatures, humidity and substrate all contribute to the success of keeping animals healthy.
Regardless of the size and type of housing you choose; housing should provide enough heat and thermal gradient to achieve success. Fortunately, Bolivians can tolerate a wide range of temperatures, although neonates do require more specific care than adults.
There are many different housing options available on the market today including glass aquariums, wood (Melamine) terrarium , plastic (PVC) terrarium, and reptile racks used to house multiple animals in a single system.
Each of the options have their pros and cons, however in recent years the PVC options have become popular because they’re easy to clean, they maintain temperature and humidity, and don’t rot over-time like wooden terrarium are prone to under high humidity.
| Material | Description |
|---|---|
| PVC | Polyvinyl chloride (PVC) is extremely popular these days for reptile terrarium. The material is exceptionally light so assembled terrarium can be conveniently moved around if required. PVC is also fire resistant and easy to clean. |
| Industrial Melamine | Melamine terrarium were a good option back in the early days of reptile husbandry. Most people tend to use PVC terrarium today, although melamine is still popular for reptile racks. |
| Polypropylene bins | Clear Polypropylene bins are a material that is used for totes and storage bins. These are typically used in reptile-rack systems, economical, and easy to clean. |
| Polycarbonate bins | Like Polypropylene, Polycarbonate bins are transparent, providing a much better view of the animal. However, they’re more expensive. |
Terrarium Size
Selecting an appropriate terrarium size is easy, provided you have the room. We house our neonate boas in Rubbermaid/Iris bins (see table below). Inexperienced keepers may view these bins as being small; however, most boas benefit from small, dark lit bins because they provide them with more security. In the case of small Boas such as neonates or even some sub-adults, small to medium bins work well.
For adult boas (especially large females), large terrarium at least 121 cm (48″) will provide an appropriate amount of room. Keepers with especially large females 1.8 meters (6 ft.) can opt for larger terrarium to provide extra living space.
The table below provides a minimum terrarium size for the Bolivians. In our experience, larger is better.
Note: Measurements are in Length x Width x Height
| Neonates | Sub-adults | Adults | |
|---|---|---|---|
| Males | – | 91x60x76cm (34″x18″x7″) | 91x60x30cm (48″x24″x12″) |
| Females | – | 121x60x30cm (48″x24″x12″) | 182x60x30cm (72″x24″x12″) |
| Both | Bins typically 30x20x16.5cm (12″8″6.5″) | – | – |
Temperature
Bolivian Short-tailed Boa Husbandry tend to be more forgiving than other Boas, especially when it comes to temperature. Adult Bolivians can tolerate much colder temperatures in the winter months than other boas. This is especially important when it comes to times such as breeding trials, when keepers tend to cool their animals to induce them to breed.
I prefer to cool all our animals, regardless of their age and size. We choose this because in the wild animals are subjected to the same temperature regimes regardless of their age. In some cases, one could argue that adult boas are purely terrestrial in nature and therefore may be subjected to different temperatures than that of neonate or younger animals that may be semi-arboreal (this is often the case for younger boa species, which attempt to achieve greater security by being elevated off the ground). However, we believe there is more benefit to all animals experiencing the same temperature changes throughout their lives.
Given the information above, we provide the following temperature requirements for Bolivian Boas:
| Time of Day | Temperature |
|---|---|
| Day time hot spot | 29-30.5 C (85-87 F) |
| Day Time High (ambient) | 26-27.5 C (79-82 F) |
| Nighttime low (ambient) | 23-25.5 C (74-78 F) |
Maintaining a thermal gradient for boas is an important part of husbandry. This is the main reason for providing an ambient terrarium temperature and hot spot. When boas are provided a hot spot, they will move back and forth from this spot during a typical day. As an animal prefers warmer conditions (typically after ingesting a meal) they can bask in the “hot spot”.
When terrarium are constructed with the heat source at one end of the terrarium, this creates a thermal gradient in the terrarium where the opposite end of the terrarium can be naturally cooler, allowing the animal to choose what temperature it would like to maintain.
Heating can be provided using ceramic heat emitters, heat lamps, radiant heat panels, under- heat pads, and the popular Heat-tape method (under-terrarium heat tape). We prefer to use a combination of heat tape and radiant heat panels.
If you house your boas in a room that is not heated to at least 24C (76F), you may struggle to maintain adequate ambient terrarium temperature. In this case, we would suggest using a Radiant Heat Panel (RHP) as a minimum. These panels are easy to use and produce more heat than heat tape.
Accurately Measuring Temperature
Measuring the temperature of the terrarium and animal itself is something new hobbyists often struggle with. Often relying on pet store stick-on thermometers that are inaccurate, and only provide the temperature of the surface to which they’re attached.
It is recommended that keepers invest in a Temperature Gun. These are easily found in your local hardware store. Using a temperature gun is a much more accurate way of measuring the temperature of the hot spot in the terrarium, cool spot, and the boa’s physical body temperature. Moreover, this is especially important for gravid females, or neonates.
Humidity
Humidity requirements for Bolivians are easily met by simply spraying the enclosure weekly with a water bottle. To facilitate humidity, spraying the substrate (more on substrate below) is the best method of maintaining humidity, especially for those substrates such as coca mulch, cypress mulch, or another substrate that has high absorbency.
Furthermore, humidity is especially important for neonate Bolivians because they can be more susceptible to dehydration than larger boas. All boas benefit from higher humidity when it comes to the shedding process, as the much-needed moisture will aid the boa in shedding a solid, one-piece shed. Failure to have enough moisture in the terrarium may lead to shedding problems, and animals may have difficulty shedding properly, resulting in manual removal of stuck shed.
| Time of Day | Relative Humidity (%RH) |
|---|---|
| Day time high (DTH) | 65-75% |
| Nighttime low (NTL) | 65% |
Accurately Measuring Humidity
Accurately measuring humidity is challenging, especially given the plethora of “Humidity meters” on the market which are of low value. Pet stores often sell stick on hygrometers that are inaccurate. However, there are products on the market such as the EXTECH hygrometers that are much more accurate and provide a reliable means of tacking humidity. We use the EXTECH Big-digit Hygro-thermometer for animals in our collection.
Substrate
There are several choices when it comes to substrate used for boas such as mulches including: cypress, coca (crushed or mulched), newspaper, and paper towel. We prefer to use coca mulch for sub-adults and adults, and a peat moss-coca mulch mixture for neonates. Both adults and neonates will benefit from a deep substrate. We prefer to provide at least 8 cm (3″) of substrate for adults and two inches for neonates. If you provide enough substrate for your boas, you’ll find that they often push themselves underneath the substrate.
Alternatively, another other added benefit of using a mulch substrate as opposed to newspaper or paper towel is that mulch substrate will hold humidity longer and more consistently than paper products. This means that you’ll have to spray the enclosure less often as well.
| Type | Pro | Con |
|---|---|---|
| Coca mulch (crushed or mulched) | Holds moisture well, resistant to mold, aesthetically pleasing | More expensive than alternatives, not always easy to obtain. |
| Cypress mulch | Holds moisture well, easy to obtain | Not resistant to mold. |
| Newspaper | Economical, convenient: delivered to your front door, easy to replace | Not aesthetically pleasing. |
| Paper towel | Economical, easy to replace | Not aesthetically pleasing, only suited for neonates. |
| Aspen | Economical | Doesn’t hold moisture well, molds easily. |
Lighting
While Bolivian Boas are primarily nocturnal and do not require UVB lighting, providing UVB lighting in their enclosure can have several benefits for their overall health and well-being. UVB lighting helps reptiles to synthesize vitamin D3, which is essential for proper bone growth and metabolism.
In the wild, reptiles receive UVB radiation from the sun, which allows them to synthesize vitamin D3. However, in captivity, reptiles often do not receive adequate UVB exposure, which can lead to vitamin D3 deficiency and related health problems. Providing a UVB light source in the enclosure can help to prevent these issues.
In addition to aiding in vitamin D3 synthesis, UVB lighting can also help to regulate the reptile’s circadian rhythm, which can positively impact their behavior, activity levels, and overall health. It is important to note that UVB lighting can degrade over time and should be replaced every 6-12 months to ensure adequate UVB exposure.
When selecting a UVB light source for an Boas enclosure, it is important to choose a bulb with an appropriate UVB output for the size of the enclosure. It is also important to provide a basking spot where the snake can thermoregulate and receive direct exposure to the UVB light.
It is important to note that while UVB lighting can provide many benefits to Boas and other reptiles, it should not be used as a replacement for proper temperature, humidity, and nutrition. A balanced and appropriate diet, proper temperature and humidity levels, and a clean and well-maintained enclosure are all essential components of proper Boa care.
Cleaning
Maintenance of the terrarium is a daily, weekly, and monthly affair.
Water bowls:
- Daily water bowls are visually inspected and disinfected/replaced when polluted with substrate or fecal matter using an appropriate disinfectant (see more on disinfectants below).
- It’s also recommended to replace water each time an animal has defecated in the terrarium whether the water is polluted or not. The water may have been contaminated in the process and it may not be visual to the keeper.
- Otherwise, water bowls are disinfected and replaced once weekly.
Spot cleaning:
- Spot cleaning is also a daily task. Any fecal material found in the terrarium is removed and disposed of. Any substrate that is polluted by fecal material is discarded as well.
Substrate replacement:
- Substrate replacement depends on the substrate type used for your boa. Paper products such as paper towels or newspaper are to be replaced immediately upon defecation. In the case of mulch substrates, our suggestion is to replace the mulch every two to three months, depending on the condition of the substrate.
Disinfectant:
- Choosing an appropriate disinfectant to clean your reptiles’ water bowls, terrarium, and accessories is essential. A popular product in the pet trade today is F10 Disinfectant. I’ve used and recommended this product.
Conclusion
In conclusion, Bolivian short-tailed boas are beautiful, hardy, and rewarding animals that are a real pleasure to keep. Their minimal maintenance and good demeanor make them excellent boas for both new keepers and experienced hobbyists.
References
- Boa constrictor (MURPHY & CRUTCHFIELD 2019) – The Reptile Database (Accessed Online, 2017)
- Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) – Appendices I, II and III (Accessed Online, 2017)
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