Introduction
When I was in elementary school (back around 1950!) there was a small
museum in my home town that "checked out" animals to children for a couple of weeks much as a library will check out books. The animals were usually hamsters and lizards and other
creatures that were safe and easy to take care of. The parents loved the idea! They could satisfy a child's "need" for a pet but avoid long-time commitments. It also allowed families
to try out an animal to see if they really wanted to have one permanently. One of the animals that the museum did NOT check out to families (in spite of my pleas) was a beautiful
boa constrictor. How I loved that snake! I went every possible opportunity I had to hold the snake. I loved the feel of it, the colors, and its docile acceptance of me. I promised
myself that I would own a boa constrictor some day.
Fast forward ahead to about 1990, Chapel Hill, North Carolina. I walked into my local pet store (one of my favorite places!) and staring me in the face was the most
beautiful five foot boa that I had ever seen. A private party was selling it through the pet store. I worked out a deal to buy it "by the month." The pet store liked
the deal because they could continue having the snake on display until I paid it off. Now B. C. (as in, Boa Constrictor) is a popular member of my science
classroom. It has been held by hundreds of school children from kindergarteners to seniors in high school. If you have a fondness for large snakes, this species is a
great choice. They are delightfully big but they don't get so large that you need to put an addition on to your classroom!
Scientific Name
Boa constrictor is the actual scientific name of this attractive snake. The boa constrictor belongs to a family called Boidae that includes all the large pythons and
boas. This family is unique in that specimens show signs of vestigial limbs. You can find little spurs on each side of the cloaca in many organisms (particularly males)
and their skeletons show pelvic girdles. These structures are thought to be remains of their connection to their lizard-like ancestors.
General Physical Description
Boas have been known to reach a length of about 13 feet but that is rare. Typically, they will reach four to nine feet. The snake is full bodied and has a large triangular
head with a narrow neck. There is a lot of variation in color but generally the snakes are silver gray with large blotches of dark brown which becomes reddish brown
as they approach the tail - hence the term "red-tailed boa." My snake, B.C., actually has a beautiful yellowish background which is more common among the Peruvian or
Colombian boas. The tail of the boa constrictor is considered to be slightly "prehensile" meaning that it is used somewhat like a limb. It can be wrapped around a branch
and then the boa can use its mouth and the rest of its body to grab food and bring the dinner back to the branch. If you get a boa, be prepared that lifetimes of 20
years or more are not uncommon!
Behavior
The common boa is primarily terrestrial but will spend some time in trees (arboreal). Boas tend to sleep during the day and are active at night (nocturnal). They will
spend the day coiled on the ground and then go up into the branches of trees during the night while they hunt for food. They will bask in the sun first thing in the
morning. Most boa constrictors are fairly docile. They will flick their tongues frequently when moving (a sign of good health). The Colombian boas tend to be the most
docile.
Reproduction
Boas are ovo-viviparous, meaning that the babies emerge from eggs within the mother and are born live. I have never bred boa constrictors but I have talked to people
who have. The snakes need to be about two years old and of comparable size for successful breeding. Females have a large window of time within which breeding may be
successful. Most breeders put their snakes in darkness for a month (November or December) and expose the snakes to lower temperatures - 70-75 degrees Fahrenheit. Then
the snakes are warmed and will usually breed. However, other breeders do not think that the cooling time is necessary for boas. When the snakes are reluctant to eat,
that is usually a clue that breeding season has arrived! The females should not be fed again until after breeding takes place. The male, when introduced to the female,
will show very rapid tongue flicking as he senses the pheromones that the female is producing. The male will crawl on top of the female and "squeeze" her in short intervals.
He stays with her wherever she goes. This period of courtship may take weeks. The male will use his spurs to line up their cloacas. Then the male will insert one of
his hemi-penes into the female¹s cloaca and deposit sperm. Mating may last for many hours. The male will curl his tail in the air and twitch it during the long
mating process. The gravid females will need a lot of water, will continue to eat and should not be handled unless absolutely necessary. The female will defecate and
pass the solid type uric acid before the babies are born; she will also be very restless. Typically, the babies are born at night and may still be in their tough sac
and have remaining yolk sac attached. The mother snake can be removed and fed. The babies will shed when they are nine to ten days old and can be fed pinkies or fuzzies
before or after the first shed.
Classroom Habitat and Food
I keep my boa constrictor in a large plastic cage with sliding glass doors and a very secure lock! I include a heavy tree branch for nocturnal climbing. The substrate
can be newspaper, pine shavings or Supersoil, sold in nurseries. If soil is used, the prekilled food should be offered on newspaper. But newspaper is a perfectly adequate
substrate and makes clean up very easy. An above ground shelf can be provided also. I have a heating unit with a thermostat that goes under part of the cage. There should
be warmer and slightly cooler areas in the enclosure so that the boa can regulate its own temperature. Many people who keep snakes feed them prekilled prey; this avoids
some suffering in the prey and also keeps the snake from being bitten by its dinner. My snake will eat prekilled prey but I do not always have it available and will
give my snake live rats when necessary. The boa constrictor is a very efficient snake. The kill is quick and efficient. I have been unable to accomplish any of the suggested
methods for me to kill the prey, and I figure that the snake is adapted to this process - not me! I usually feed my boa two large rats every two to three weeks. This
avoids too rapid growth but seems to have kept B.C. healthy for many years.
Native Habitat and Role in the Environment
Boas are found in Central and South America. In the wild, the boa constrictor opts for dry open woodland and rocky slopes. It can climb very well and tends to avoid
water. This snake tolerates a wide range of climatic conditions; it can be found in arid desert-type environments as well as humid tropical forests. It eats mainly birds
and mammals.
Handling Tips
I always throw a large towel over B.C.'s head when I have opened the cage to get her out. This seems to alert her that it is not a feeding time and that I will be
removing her from the cage. She has never bitten anyone so the method has worked. Once she is out of her cage, I am careful to support her length. I put her around my
waist and let her hold on to me as if I were a large tree! I then support her head and neck with my hand. I remain calm, firm, and supportive. Generally, snakes will
be more docile the more they are handled. A nervous snake will actually produce a hissing sound so that you will have some warning. You can then calmly and firmly place
the snake back in its enclosure.
