Boa Constrictor

Boa constrictor

Order: Squamata

Family: Boidae

Related species: Boa constrictor constrictor (red-tailed boa), Boa imperator (Columbian boa)

There is some debate as to whether Boa imperator (the Central American population) is a subspecies of Boa constrictor or it’s own species. See ITIS, CABI, and Wikipedia.

Natural History Information

Range and Habitat

  • Boa constrictors are found from southern Mexico to north South America: Brazil, parts of Peru, Venezuela, Suriname, Guyana, Trinidad, and Colombia. They live in various types of land, including mile deserts, wet tropical forests, open savannas, and cultivated fields.

Longevity

  • Boa constrictors can live up to 30 years.

Ecosystem Role

  • They are important for population control of prey species.

Husbandry Information

Housing Requirements

  • Life Cycle Natural History Relevant Information
    • A large secure enclosure with a heat source on one end, providing a temperature gradient for the snake. Boa constrictors do not need an excessive amount of space but should be able to move comfortably throughout the enclosure, with space to move away or toward heat, soak in water as needed, and ideally with vertical space for climbing. Young snakes should generally not be housed in an adult sized enclosure as the large space may be stressful. As these snakes will grow quite large, they may grow through several enclosures throughout their lifetimes.
    • Bowl large and deep enough for the snake to submerge itself but shallow enough (or with branches, rocks, etc.) that the snake can move in and out with ease.
    • Hides in both the warmer and cooler ends of the enclosure.
    • Enclosures with solid sides (glass or plastic) will generally maintain humidity better than those with mesh fabric or more permeable sides.
    • Include rough and smooth areas/items/substrates to aid with shedding.
    • Younger animals are more arboreal, once they reach adult size they spend more time on the ground.
  • Temperature, Humidity, Light Cycles
  • Substrate:
    • Though not mandatory, branches or other items for climbing are ideal.
    • Substrate can vary from newspaper or astroturf to repti bark or other naturalistic bedding. Do not use cedar or pine shavings.
    • Substrate that can help maintain humidity is helpful, such as Eco Earth ground coconut fiber.
  • Social Housing/Colony Management
    • This is not a social species.
  • Other General Housing Requirements or Management information

Diet Requirements

  • Life Cycle Relevant Information
    • Younger snakes will eat more birds and other animals in trees, older snakes tend to take prey on the ground.
  • Diet under human care
    • Small snakes can eat mice of various sizes (pinkies to adult), larger individuals eat rats. One or two rats per week are generally sufficient for adult size boa constrictors. All rodents should be pre-killed before presentation in order to avoid potential injury to the snake.
    • Program snakes should be fed out of their housing containers. Large tupperware style containers with air holes work well as they can be securely fastened and the snake can be left alone to eat at its own pace. Removing the snakes from their enclosures for feeding ensures that handlers will not be confused with or connected to feeding; this reduces the chance of biting.
    • Boa constrictors may need less food in the cooler months and/or may go off feed entirely for several months at a time.

Veterinary Concerns

  • It is not uncommon for boa constrictors to go off food in the cooler months. If the snake seems fine in all other respects, this is not cause for concern. Continue to offer regularly and monitor for extreme weight loss, aggressiveness, lethargy or other abnormal behavior.
  • Can contract worms, fecals should be tested regularly.

Enrichment

  • Behavioral Relevant Information
    • This is a semi-arboreal species, more arboreal when young.
    • Boa constrictors are ambush predators.
    • They are capable swimmers.
    • They will rest under the cover of low branches and bushes.
  • Environmental Enrichment
    • Branches and elevated shelves that can support their weight
    • Novel substrates offered in a removable tray for tactile stimulation
    • Changing out rocks, hides, and branches
  • Behavioral Enrichment
    • Food items can be drug in a trail around the enclosure if the animal is out to encourage tongue flicking.
    • With veterinary approval, browse or furniture that has been in with mammals can be very stimulating.
    • Always provide heavily scented items in small amounts and on one side of the enclosure so the snake can move away if uncomfortable. Monitor for signs of stress.

Training

  • Behaviors Trained
  • Reinforcers used & schedule of reinforcement

Programmatic Information

Messaging Themes

  • Threats and Conservation Status
    • This species is considered vulnerable and is listed in CITES Appendix II. All species of boids (boas) are endangered or restricted. Hunting for leather and meat and the live animal trade has reduced their numbers, as has the reduction of their forest habitat.
    • In general, animals seen at the zoo do not make good pets. Most have specialized dietary, veterinary, housing, and social needs that are difficult or impossible for even dedicated pet owners to meet. Always ensure that your future pet has not been taken from the wild. Captured animals are typically mistreated by profit-motivated traffickers and dealers, resulting in many animal deaths; well-meaning animal lovers may feel like they are rescuing animals by purchasing them but are really perpetuating the cruelty. In addition, many exotic pets are released by their owners when they become too dangerous or demanding, often with devastating effects on local ecosystems. Animals that should never be kept as pets include all bats, primates, and exotic carnivores. Birds, fish, and reptiles have specialized needs, are frequently wild-caught, and damage the local environment if released; guests should be advised to educate themselves and proceed with caution. Domestic dogs and cats are almost always the best option! Many deserving animals are available for adoption at animal shelters.
  • Interesting Natural History Information
    • Background color generally matches the ground: ruddy brown becoming rich bright red on the tail. On the back is a row of large, tan-colored saddles which gradually become lighter towards the tail where they break into half rings of pale cream color, in vivid contrast to the red. Recently shed boas may have an iridescent appearance. Adults can reach 5 to 12 feet in length.
    • Boa constrictors are ovoviviparous, meaning they give birth to live young. Gestation period is 4 to 8 months, and there are usually 21 to 64 offspring per clutch, although clutch size can range from 6 to 65 young. Newly born snakes are about 24 inches long.
    • Among the large snakes, boas are the least inclined to enter water, although it will do so occasionally. They have arboreal tendencies, and are nocturnal. Generally, boa constrictors are very docile. They can hiss very loudly.
  • Did you know…
    • Boas are one of the most primitive of snakes, and have vestiges of a pelvis and hind legs (small spurs on either side of the vent) and well-developed, paired lungs.
    • Constrictors do not actually crush their prey by squeezing it. Instead, each time the prey exhales, the snake squeezes a bit tighter so the prey cannot take a breath in, and suffocates.
    • Boas are the only one of the large snakes which lives near the United States.

Handling & Presentation Tips

Use Guidelines

  • Should not be handled for 2 days after eating.
  • Should not be handled from the time they go “blue” (eyes turn opaque) until after they shed.
  • It is helpful to have a DO NOT USE sign keepers can hang on the enclosure. Some institutions also include the date, “I was blue starting on ___,” or “I was fed on ___.”

Public Contact and Interaction Guidelines

  • Public can be permitted to touch this snake while it is being held by a handler. The handler should stay aware of the head location at all times, redirecting as necessary to keep it facing away from guests.
  • Encourage guests to use two-finger touching, moving down the body (in the same direction as the scales) in order to prevent accidental lifting of scales.
  • Lee Richardson Zoo: Once large they become more difficult for some handlers to manage but remain docile and popular with handlers and audiences.
  • Zoo New England, Stone Zoo: Can get large (2 handlers needed) and extremely temperamental.

Transportation Tips

  • Brandywine Zoo: During cool weather (under 65°F), supplemental heat is provided with a hot water bottle set to one side of the cooler. Wrap bottle with newspaper for lizards or snakes traveling with the bottle loose, to make cleanups easier in the case of defecation while traveling.

Crating Techniques

  • Brandywine Zoo: reptiles travel in a Coleman style coolers that have been amended with extra ventilation holes on the lid (with a wood-burning tool). Small and medium sized snakes travel inside an inside-out, knotted pillowcase. Large snakes travel loose in the cooler that is also bungeed shut.

Temperature Guidelines

Acquisition Information

  • After looking at other AZA institutions for surplus animals, check with your local herpetological society and reptile rescue organizations.  Many of these animals are purchased by the public at reptile stores and expos and owners are unable to keep them for their whole lifespan. If purchasing, look for a reputable breeder to avoid wild caught specimens.

Documents

Resources

Contributors and Citations

  • The Philadelphia Zoo
  • Houston Zoo, Natural Encounters

Comments from the Rating System

  • Children’s Zoo at Celebration Square: We have a 6-ft (approximate) female red-tail. She is extremely docile through conditioning. I put that she is good for beginner handlers because she is so calm, but she is large and heavy so she is in our moderate level. She is a 2-handler rule due to her size. 2 people always have to be around but one person can handle her if she will wrap around the body (she is lazy and doesn’t like to do this so we usually have 2 handlers actively holding her). The other handler will be support if she will wrap. She is a big attention draw for the public and is great for educating about why large snakes are not good pets since she’s so big but not at all fully grown. People are fascinated with snakes even if they’re “afraid” and she is great for people getting over their fear since she’s so calm. She is hands-on for the public and does extremely well with being touched and manipulated for public to see the different scales.

Cover Photo: D. Norton, via Brandywine Zoo