Enclosure: Temperatures & Heating

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Reptiles can’t be kept in the same conditions as a dog or cat because they are cold-blooded, which means that they rely on their environment to regulate their body temperature. The average temperature of the human body is 98.6°F, and because we’re warm-blooded animals, we don’t have to worry about staying at the right temperature because our bodies maintain the right temperature automatically. Now imagine that you couldn’t control your own body temperature, and you had to stay at that temperature using outside means (and no, a sweater won’t work). The easiest way to do this would be to turn up the thermostat in your house from 72°F to 98-99°F, right?

Fortunately, we don’t actually have to do that. And reptiles are incredible because their bodies can tolerate a wide range of temperatures — in fact, experiencing changes in temperature over the course of a day and depending on location is very healthy for a reptile. But that’s what life is like for reptiles, and since your boa isn’t in the wild, it’s your job to supply a stable heat source that they can use as needed.

Boas have been proven to thrive within this temperature gradient:

  • Basking surface: 90°F (32°C)
  • Basking air temp: 80-85°F (28-29°C)
  • Cool end: 75-80°F (24-26°C)

Overall your boa constrictor enclosure should have different areas that range from 75°F to 90°F for a complete thermal gradient.

Heating devices can be turned off at night to cause a nightly drop in temperature, which evidence suggests is the best practice for the long-term health of the animal. Only if temperatures are lower than 75°F at night does night heating (which should only be accomplished with a lightless heat source like a DHP or RHP) become necessary.

Special note: It is speculated that B. c. constrictor particularly benefits from seasonal fluctuations in temperature, even if a keeper does not intend to breed. Experts recommend a 14-hour day during summer and then a drop to 75-78°F (24-26°C) air temperature during winter, with an 8 hour day.

Boa Temperature Guidelines - boa basking on a branch
Contributed by James Greengrass

Temperature Data

Wild boas have been recorded active at temperatures as low as 62°F (17°C) and up to 104°F (40°C) between the hours of 7am and 7pm, although most of the data is clustered between 90°F (32°C) and 66°F (19°C). This temperature range contradicts what most keepers assert as “the best,” but proves that with correct husbandry, these animals are hardier than previously thought. Do you think that nature always stays at the perfect temperature? Of course not, and these animals are adapted to deal with the fluctuations of their region without getting sick. The key is to create a full temperature gradient so your snake can warm up and cool down as desired. The hottest areas will be closest to the heat source, and the coolest areas will be farthest from the heat source.

  • Chiaraviglio, Margarita, et al. “Intrapopulation variation in life history traits of Boa constrictor occidentalis in Argentina.” Amphibia-Reptilia 24.1 (2003): 65-74.
  • Waller, Tomas, et al. “Ecological correlates and patterns in the distribution of Neotropical boines (Serpentes: Boidae): a preliminary assessment.” Herpetological Natural History 3 (1995): 1.
  • McGinnis, Samuel M., and Robert G. Moore. “Thermoregulation in the boa constrictor Boa constrictor.” Herpetologica 25.1 (1969): 38-45.

Tools for creating the perfect boa temperature gradient:

The best way to create a temperature gradient for your boa will be to place the heat source on one side of the enclosure. This will make sure that there is an area of cooler temperatures that your boa can retreat to on the opposite side of its habitat. Don’t be alarmed if your snake spends most of its time on the cool or mid-range area; boas typically only use the hot spot for digesting after a meal.

Heat Lamp

Heat lamps are still a controversial heat source for snakes, but they are one of the most natural ways to create the right temperature gradient in your boa’s enclosure.

If you are using a glass terrarium or other enclosure with a mesh top, I recommend using a dual dome-style heat lamp fixture with a ceramic sockets. (This lamp is my favorite for larger reptiles.) That way the mesh creates a barrier between the hot bulb and your snake, and you can create a larger basking area for healthier, more effective basking.

If the bulb(s) must be installed inside the enclosure, you will need bulb cages like this to prevent burns.

There are many different types of heat bulbs on the market, from reptile-specific brands to ordinary bulbs at your local home improvement store. Reptile brand halogen bulbs can work well, but they tend to be short-lived — the best one I’ve found is the Zoo Med Repti Basking Spot 100w. But I’ve had the best experience with PAR38 halogen flood bulbs, specifically the Philips 100W Halogen Heat Lamp bulb.

What wattage? This is a common question with no solid answer, sorry! What wattage bulb you will need depends on room temperature, enclosure height, and other factors. What works for one person won’t always work for another, which is why I like plug-in lamp dimmers so much. When in doubt, try the higher-wattage bulb first. It’s also best to do your testing BEFORE you bring home your new snake.

  • Pro tip: Be sure to buy white or clear bulbs rather than red, blue, black, or whatever other color they’re offering. Colored bulbs often do more harm to a snake than good.

Deep Heat Projector (DHP)

The Arcadia Deep Heat Projector is essentially a ceramic heat emitter with almost all of the benefits of a traditional heat bulb — just no light. If for some reason you don’t want to use a heat bulb for heating your reptile’s enclosure, this is the next best thing. Use the DHP by installing the bulb inside a ceramic-socket dome heat lamp in place of a conventional heat bulb. Note that the DHP does not produce light, so you will need an additional light source. If you are using UVB, this shouldn’t be a problem. For best results, place a piece of flagstone or stone tile directly underneath the DHP to absorb heat and create a nice cozy basking spot.

Radiant Heat Panel (RHP)

Heat panels act like heat lamps without the bulb. These are definitely the most expensive of the 3 heating options we recommend, but can be well worth the investment if you’re struggling to maintain optimal ambient (air) temps. Unlike heat pads, these are installed on top of the enclosure for natural heat, which radiates down to create a zone of warmth on one side of the enclosure. Make sure to connect your radiant heat panel to a proportional thermostat (not thermometer — and yes, there’s a difference) to maximize the RHP’s lifespan as well as make sure it doesn’t accidentally get too hot.

Like the Deep Heat Projector, radiant heat panels don’t produce light, so you will need some kind of light source to help regulate your snake’s day/night cycle. Reptile Basics’ heat panels are trusted by many and widely considered to be some of the best in the industry.

Do not use heat tape or a heat pad

Heat tape is a heating element in the shape of a long cord that can be distributed however you want under/around the enclosure. Handy, right? It used to be very popular with snake enthusiasts (and still is with breeders) because of this convenient feature. Heat pads and mats are installed on the bottom of an enclosure to warm the substrate above. These are also very popular with snake enthusiasts. However, they tend to struggle when used with wood enclosures or a thick substrate layer, and fail to affect air temperatures.

Both heat tape and heat pads must be used in conjunction with a thermostat to prevent them from getting too hot, and without this tool it is impossible to control your boa’s temperature gradient.

Both products are used with the same assumption that snakes need “belly heat” in order to digest their food properly. However, the truth is that the whole concept of belly heat is bogus! In nature, warmth comes from above (the sun), not from below (the ground). In fact, when reptiles get too hot they will retreat underground to cool off. Using overhead heat sources like heat lamps mimics the effects of the sun and how boas evolved to receive warmth — by laying on top of sun-warmed surfaces and thereby receiving heat from both above and below. To recreate this effect in your enclosure, you can place a piece of slate, flagstone, or even wood underneath the heat source to create the perfect basking surface.

Boa Constrictor Temperatures - boa basking under guarded lamp
Contributed by Marcel Grafe

How to measure enclosure temperature

As you may have noticed, surface temperature needs to be warmer than air temperature. That is because basking surfaces like rocks and branches tend to warm up faster than the air does. Measure basking site temperature with an infrared temperature gun and use a digital thermometer (not gauge) for air temperature. It may seem redundant at first, but trust me, you’ll get much more accurate readings this way. Using only one device or the other will give you inaccurate readings that can put your boa’s health at risk.

Do boas need heat at night?

Possibly. Night temperatures can (and should) drop to around 75°F (24°C) at night with no ill effect. This means no colored “night” heat bulbs. And in fact, providing a nightly drop in temperature is actually better for your boa’s health! However, if your room temperature gets lower than 75°F at night, it is recommended to provide a lightless heat source like a deep heat projector (DHP) or ceramic heat emitter (CHE) attached to a proportional (dimming) thermostat to keep things at the recommended 75°F. Temperatures should absolutely go no lower than 72°F (22°C).

Special note: B. c. orophias and B. c. nebulosa may be less cold-tolerant than other boas. Using a lightless nighttime heat source to keep temperatures around 80°F (26°C) night is highly recommended for success with these subspecies.