Robert Harper’s Rainbow Boa Care
Sheet
I’ve kept rainbow boas off and on for about 15 years. They were one of my first reptilian
loves and the first species of snake that I bred in captivity. Rainbow boas make excellent
pets and are not any more difficult to keep than a boa constrictor as long as you keep in
mind that they cannot get too hot and that they need to have access to areas of high
humidity.
Size
Rainbow boas are born approximately 12-16” long (depending on
subspecies) and will grow to between 4-7’ as adults with 5-6’ being average
for adult Brazilian rainbow boas. In my experience, females grow larger on
average than males.
Temperament
Baby rainbow boas can be quite nippy, but they quickly calm down with
regular handling. Adults that are regularly handled are typically very tame.
Housing
Baby rainbow boas can be housed comfortably in a 10 gallon aquarium or
comparably sized enclosure providing that it has a secure lid (they are very
good at escaping). Alternatively, they can be kept in appropriately sized
plastic “shoeboxes” or sweater boxes until subadults. The size of the
enclosure should increase with the size of the boa. Adults are best housed in
cages that are 4’ x 2’ x 1.5’, though a cage that is 3’ x 2’ will suffice for a
single adult. I recommend housing them individually, but I and several
others I know have successfully maintained several adult rainbow boas in
the same cage without incident. Males should not be housed together,
though, since they may fight.
A variety of substrates can be used with rainbow boas. Options include
newsprint, aspen shavings, Care fresh, paper towels, and cypress mulch.
Cypress mulch is a fantastic substrate as it holds humidity very well, but it
isn’t too available in some places and care must be taken when feeding boas
so that it isn’t ingested. Care fresh is available at many pet stores, smells
clean, holds humidity decently well if misted, and doesn’t mold as quickly
as aspen shavings. I use it for baby as well as adult rainbow boas. If
newsprint is used, a humid hide box should definitely be provided.
Regardless of the substrate used, it should be kept clean and free of mold.
Temperature & Humidity
A temperature gradient is very important. Temperatures on the cool side of
the enclosure can get down around 75 degrees; ambient temperatures on the
warm side can be up to 85 degrees. Heating of the enclosure can be
accomplished with a heat pad, heat tape, or basking lamp on one side of the
enclosure. The key is that the snake be able to escape the heat if it needs to.
Heaters should be controlled with a reliable dimmer switch, rheostat, or
thermostat (the best option is a proportional thermostat). Several suitable
thermostats are commercially available. I like the Herpstat from Spyder
Robotics personally. Night time temperatures can safely drop into the 70s.
Humidity is also very important for rainbow boas. I’ve heard several people
say that rainbow boas need humidity as high as 90 percent to do well, but
that has not been my experience. I have found that a relative humidity of
around 70 percent is sufficient for baby boas (with a slight increase during
shed cycles), while even lower overall relative humidity can be sufficient for
adults provided a humid hide box is provided. Such high humidity can be
maintained by daily misting and the presence of a large water bowl in most
cases. If an enclosure with a screen top is used, ½ to ¾ of the screen can be
covered to reduce moisture loss. I provide a plastic box with an entrance
hole that is filed with moist sphagnum moss for my juvenile and adult
rainbow boas to retreat to.
Note that humid does not equal damp. The cage and substrate should not
always feel wet to the touch. A perpetually wet cage will grow mold and
fungus and spell health problems for your captives. If you mist your
enclosures, the substrate should not be wet within a few hours. If it stays
wet all the time, reduce the amount of misting or increase the ventilation in
the cage. While too much ventilation will make the cage dry out quickly,
too little is worse. What you really want to avoid is humidity that is too high
and temperatures that are too low; this can rapidly lead to a respiratory
infection.
Feeding
Baby rainbow boas can eat an appropriately sized food item every 3-7 days.
I typically start mine on fuzzy/hopper mice and move up from there. Adults
will take medium to large rats every 7-14 days. One of the great things
about Brazilian rainbow boas is that it is rare to find a problem feeder.
Breeding males and females may refuse food; this is normal.
Rainbow boas can easily be trained to accept pre-killed or thawed rodents,
which I highly recommend. A medium adult rat can inflict a serious bite on
a snake if it has the opportunity.
How I Keep Juveniles
I have personally used a variety of approaches to keep rainbow boas
successfully. The following is the way I currently raise rainbow boas and
the method with which I have had the most success.
I keep baby rainbow boas in a “snake rack” where each individual baby is
housed separately in a small plastic “shoebox” (usually a 4-6qt Sterilite
container or other similar plastic box). It is imperative that this box have a
tight fitting lid and be escape proof. I drill several small holes in the sides of
the box for ventilation. These holes must be small enough so that the baby
cannot fit through them; about 1/8” in diameter should be okay, or whatever
looks good. You don’t want to drill a ton of holes, just enough to get decent
air exchange. For very young rainbow boas I use paper towels as the
substrate and I include a small container full of dampened sphagnum moss
and a decent sized ceramic water dish (ramekins are cheap and work well
too). You may also include another “hide” spot. Little plastic or ceramic
dishes made to hold flower pots with a hole knocked out work great. My
snake rack is basically a shelf system that these boxes fit into with some 3”
wide heat tape wired across the back of every shelf to provide heat. It is
important, though, that if you use a heat source that you attach it either to a
rheostat (dimmer) or thermostat to prevent overheating. Baby rainbows
tolerate temperatures between 75-85 degrees; hotter than 85 degrees can be
deadly. During the summer my snake room stays around 80 degrees along
the wall where I keep my rainbow boas, so I just turn the supplemental heat
off. If you have a similar location that stays warm, you might find that the
supplemental heat is unnecessary, but you need to measure the temperature
(don’t guess). You can usually pick up a digital min/max thermometer at the
hardware store for about $10, and I highly recommend using one to monitor
cage temperatures. Once a day I lightly mist the tub, check the water, and
replace the paper towel if it is soiled.
I try to feed defrosted rodents to all of my snakes because it is cheaper, more
convenient, and safer since it removes the possibility of the snake getting
bitten by its intended prey and eliminates the possibility of transmitting
parasites. Rainbow boas will usually start on thawed (or “f/t” if you’re a
herper) food without any problems. I generally thaw out the food item,
place it in a plastic bag and float it in hot water to heat it up, and lay it on the
floor of the enclosure (or on a piece of paper plate if you are using
something other than paper towels as a substrate). Baby rainbow boas will
eat fuzzy or small hopper mice and will graduate to larger items as the y
grow. If you are purchasing a baby rainbow boa from me, it is feeding on f/t
food already unless otherwise specified.
I keep rainbow boas in a similar fashion for about the first two years of their
lives except that as they grow I move them over to a different substrate
(shavings or care fresh) and into larger, appropriately sized boxes. My
adults live in 3ft or 4ft long cages. I am a particular fan of Vision cages due
to their light weight and ease of cleaning and viewing.