Dumeril’s Boa Temperatures & Humidity Needs

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Recent studies suggest that UVB can be beneficial for snakes’ long-term physical and mental health. If you would like to use a UVB as the primary source of light, use a low-intensity fluorescent tube (not coil) like the Zoo Med ReptiSun 5.0 T5 HO or the Arcadia Forest 6%. These bulbs should be changed every 12 months, because even if they seem to be still working, their UVB output decreases over time.

  • PRO TIP: If you use UVB, make sure that the fixture doesn’t have a piece of glass or plastic to “protect” the bulb. UVB rays are blocked by glass and plastic, rendering that bulb you just spent so much money on completely useless. Naked UVB bulbs are effective UVB bulbs! 

Place your light on a timer to help your snake regulate its day/night and seasonal cycles:

  • Spring — 12 hour day
  • Summer — 13 hour day
  • Fall — 12 hour day
  • Winter — 11 hour day


Like all reptiles, Dumeril’s boas need a heat gradient so they can regulate their own temperature. This temperature gradient is more effectively accomplished in large enclosures than in small terrariums or tubs.

  • Basking surface: 86-88°F (30-31°C)
  • Cool zone: 70-75°F (21-24°C)

Night temperatures can safely drop down to 70-75°F (21-24°C), and is actually better for the snake’s long-term health if provided. This is typically easily accomplished by turning off the heat source at night.

Measure the temperatures that your snake is feeling with an infrared temperature gun (my favorite is the Etekcity 774) or a digital probe thermometer like the Zoo Med Digital Thermometer and Humidity Gauge.

Do not use a cheap stick-on analog or LCD thermometer, as these are notoriously inaccurate.

How to heat your Dumeril’s boa enclosure

Heat lamp

In nature, warmth comes from the sun (above), not from the ground (below). In fact, reptiles retreat underground to escape the sun and get cooler, not warmer. Providing warmth from below, as with a heat mat, is therefore unnatural and will promote unnatural behaviors. Heat lamps solve this problem by mimicking the effects of the sun and warming both the air and the ground below.

I recommend using a dome-style heat lamp fixture with a ceramic socket and a built-in lamp dimmer, like this one by Zoo Med. A high-wattage halogen heat bulb (like the 150w Zoo Med Repti Spot or the Philips 100w PAR38 halogen flood heat bulb) should be enough to create the right basking temperature, although the exact wattage depends on the height of your enclosure. If it’s a little too hot, use the dimmer switch on the heat lamp to dial it down to the right level.

  • PRO TIP: Beware “environmentally-friendly” light bulbs. These bulbs advertise a high wattage, but actually use fewer watts while maintaining the same light output as the advertised wattage. This is great for household lighting, but in a reptile enclosure you need the warmth that extra energy expenditure provides. If you can’t find a good bulb, a reptile day bulb from a pet store works, too, although it will likely have a shorter lifespan.

If you are concerned about “belly heat,” placing a piece of flagstone or slate tile under the heat lamp will absorb warmth that your snake can curl up on. In fact, I recommend doing this anyway.

Deep heat projector

If you need a lightless heat source for nighttime, a Deep Heat Projector is a good choice. Unlike traditional ceramic heat emitters (CHEs), deep heat projectors provide nearly the same wavelengths of infrared (heat) as basking bulbs, providing more effective warmth.

But what about heat mats, etc.?

Under-enclosure heating devices like heat mats and heat tape are popular for use with snakes, especially terrestrial species. And they can be used, as long as they’re controlled by a thermostat. But, in order to create the optimal gradient of temperatures for a Dumeril’s boa in captivity, we prefer to use halogen heat bulbs.

CAUTION: Do not use heat rocks!

For some inane reason, heat rocks are still being sold by pet stores as a “safe” source of heat for your reptile. Though safety improvements have been made in recent years, there is still a danger of your snake getting burned. Furthermore, they’re not a good choice for heating your enclosure, as the device only warms the rock, not the surrounding air.


Dumeril’s boas are native to the spiny thickets/forests of southwestern Madagascar, which are part of the xeric shrubland biome. Xeric shrublands are a type of desert that receive less than 250mm of annual rainfall. Because it receives so little rain, this part of Madagascar is considered quite dry. However, it’s not the Sahara desert and the habitat shouldn’t be treated as such.

According to experienced keepers, Dumeril’s boas do best with an average humidity between 40-60%. If you live in a moderate to high humidity area, this shouldn’t be hard to achieve. Occasional misting at night (with a pressure sprayer like this one) can be used to create humidity spikes, especially when the snake is about to shed. If you find that you’re still struggling with humidity levels, mix water into the substrate as needed for a more consistent increase in humidity.

  • PRO TIP: Use distilled water for misting (not drinking). Hard water stains are tough to get rid of, but using distilled also extends the life of your mister.

Keep reading:

  1. Introduction to Dumeril’s Boas
  2. The Dumeril’s Boa Shopping List
  3. Terrarium Size Guidelines
  4. Light, Heat & Humidity Requirements (YOU ARE HERE)
  5. Substrate Options
  6. Decorating Your Snake’s Terrarium
  7. How to Feed Your Dumeril’s Boa
  8. Handling Tips
  9. Common Diseases & Other Health Info
  10. Additional Resources