Boa constrictor care

Before you get one

The Royal Veterinary College asks anyone thinking of owning a boa to weigh up its size, the space it needs, the cost and the risks, because boas grow to at least 2–3 m and live 20–30 years in captivity¹. Females are usually larger than males, very few boas grow longer than 4 m, and captive boas have lived about 40 years⁶. The Reptile Database now limits Boa constrictor to South America and treats boas from Central America and Mexico as a separate species, Boa imperator, so ask which kind you are buying^7,8. Owners sometimes release boas that have grown too big, and feral boas have become established in Florida, so never let one go^10,9,7. Keeping constrictors is banned in many places: Queensland, for example, lists the boa constrictor as a prohibited invasive animal^5,9. Choose a captive-bred boa, as captive-bred reptiles are less likely to bite or carry parasites, and ask the seller about inclusion body disease, because infected boas can carry the virus for months or years with few signs^5,13.

Enclosure

The Royal Veterinary College’s absolute minimum for an adult is 183 × 91 × 61 cm (6 × 3 × 2 ft), and one veterinary hospital gives at least 1.8 m × 61 cm × 61 cm^1,2. The MSD Veterinary Manual asks for at least 0.6 m² of floor per metre of snake, which is about 1.5 m² for a 2.5 m boa³. These minimums are shorter than many adult boas, and welfare research argues for more: a review found that even sedentary snakes use a lot of space and need to stretch out, and the UK government’s Animal Welfare Committee advises that a vivarium one snake-length long and two-thirds of a length wide is acceptable only for short-term display^12,11. Boas are born 30–60 cm long and reach adult size in 3–4 years, so plan the adult enclosure from the start⁹. Use a well-ventilated wooden or fibreglass vivarium with hides at both ends and sturdy branches, because boas like to climb¹.

Heat and light

The Royal Veterinary College recommends a basking spot of up to about 32 °C from a light that is on all day, a cool end of about 24 °C, and background heat so nights stay above about 24 °C¹. Other sources differ by a few degrees: the MSD Veterinary Manual gives a preferred air range of 28–31 °C with basking spots about 5 °C warmer, and one veterinary hospital gives 27–29 °C by day, a basking spot of up to 35 °C and nights of 21–27 °C^4,2. Put every heater on a thermostat and guard it, and keep heat mats to no more than 25–30% of the floor^1,2. Never use “hot rocks”, which often burn larger reptiles³. A low-level UVB lamp on for 12 hours a day is recommended^1,4.

Humidity and water

Sources differ widely on humidity: the Royal Veterinary College gives 50–80%, one veterinary hospital at least 50–70%, and the MSD Veterinary Manual 70–95%^1,2,4. Raise the humidity slightly when a snake’s eyes turn cloudy before a shed, and give it a hide with damp sphagnum moss as a humid retreat^17,2. Do not reduce ventilation to hold humidity, because damp, stale air causes skin and respiratory disease³. Provide a water container big enough for the snake to submerge in, and change the water daily¹.

Feeding

Boas start on pinky mice and move up to larger prey such as rats; adults can be kept on adult rats or suitably sized rabbits^1,2. One veterinary hospital advises prey no wider than the snake’s mid-body, given weekly to juveniles and every 10–14 days to adults². Offer frozen prey thawed and warmed to about 37 °C, or freshly killed prey^1,2. Never feed live rats: a veterinary manual describes a feeder rat that attacked a boa and exposed its spine¹⁴. Low temperatures, overfeeding and handling soon after a meal are common causes of regurgitation². Feeding a large snake away from its usual enclosure, and not on loose bedding it could swallow, may reduce feeding-frenzy behaviour when you open its home enclosure¹⁶.

Handling

A boa strikes when it feels threatened, and a bite, especially from a large snake, can be painful and cause a serious wound, although it is rarely dangerous⁹. The RSPCA’s handling advice for pythons applies: support the whole body with one hand near the head and the other nearer the tail, never grab, and leave a snake that pulls its neck into an S shape for another time¹⁸. Wait 48 hours after a meal, avoid handling during a shed and wash the smell of prey off your hands first^18,2. The UK government’s Animal Welfare Committee advises that a snake too large to be managed properly should not be kept¹¹. Wash your hands after handling, because reptiles can carry Salmonella¹.

Health and when to see a vet

Book a health check soon after you get a boa and then once a year, and keep a new snake apart from others for 3–6 months^17,2,3. Inclusion body disease, caused by a reptarenavirus, should be considered in every sick boa; it cannot be cured, and it spreads through body fluids and snake mites¹³. See a reptile vet if you notice:

• weight loss, regurgitation, poor sheds, or neurological signs such as odd tongue flicking or failing to turn the right way up, which can be signs of inclusion body disease¹³;
• wheezing, difficulty breathing or discharge from the mouth, signs of respiratory disease, which is very common in boas²;
• red spots or cheesy material in the mouth, signs of mouth rot¹⁵;
• mites, which can cause serious disease and spread inclusion body disease^2,13;
• loss of appetite, loose droppings, difficulty shedding or lumps²;
• burns or wounds, often from unguarded heaters or live prey¹⁴.