If blood python husbandry myth #1 is "You have to keep them hot," then myth #2 must be, "You have to keep them wet." Since we've covered ideal captive temperatures & how to create them, let's now address the issue of humidity. We'll cover understanding humidty in a captive environment, how to control and maintain it, problems that may occur from keeping a blood python too wet or too dry, and how to remedy such issues.
Humidity is more than just water in a cage. It's the amount of moisture in the air within that cage. Warm air holds more moisture than cool air. In a snake enclosure, thisamount of moisture is influenced by ambient humidity in the room, evaporation from the snake's water bowl, and even from your python's respiration. It is also influenced by the amount of ventilation in your python's cage or tub, and direct actions like misting the enclosure with a hose or sprayer.
As with proper temperatures, correct humidity levels for blood & short-tailed pythons are often greatly misunderstood. The prevailing misconception regarding humidity for these species is that it must be exceptionally high all the time, such as 80%-90%. Even though these snakes hail from an area of the world with 70% average annual humidity, is it really necessary to provide such high levels under captive conditions? Actually it isn't, and like many other aspects of blood python husbandry, proper humidity is all about creating a happy medium.
Blood & short-tailed pythons in captivity don't require wet cages, beaded with condensation. In fact, 60% average humidity seems to suit them just fine. It's not necessary to go to extreme measures to create this level of humidity when you're using an enclosure that easily supports stable temperatures & has sufficient ventilation. You don't even need fancy equipment to check humidity levels - your short-tailed python's shedding habits are a great indicator as to whether or not humidity is too low. If the enclosure is consistently too dry, your python will most likely have stuck sheds or heavily dimpled skin & spectacles. If it is too wet, the snake's skin will take on a crinkled, shiny appearance from prolonged exposure to excessive moisture.
When you think about it, the stories of blood pythons needing hot, wet enclosures and being susceptible to respiratory problems make a lot more sense - what was intended to be the "cure" was actually the problem in this common husbandry mistake. Constant exposure to high temperatures = stress = compromised immune system = lowered defenses against opportunistic bacteria & fungi growing in a wet environment = sick snake. Since illnesses in snakes are much easier to prevent than to cure, that balancing act of "not too wet, not too dry, but just right" is an important aspect of effective husbandry.
Creating & Measuring Humidity
So how does one go about establishing the correct level of humidity for his or her blood python? As previously mentioned, with the right caging this isn't too difficult. For starters, we take the approach that it's safer for a python's cage to to be too dry than too wet. This not only reduces the chance for health problems, but is also easier to correct. It's much simpler to soak a snake with a stuck shed, or lightly mist a cage with water than completely strip and dry an enclosure that is sopping wet.
Our adult and juvenile snake rooms are calibrated to approximately 60% relative humidity year-round. To maintain this level, we run humidifiers for roughly 6 months out of the year. Our Midwest winters are extremely dry and sometimes last well into mid-March or even later. Without the use of humidifiers during this time average humidity drops to approximately 25%, which we feel is uncomfortably dry. While we do prefer too dry over too wet, it is important to note that extended exposure to very dry conditions can also prove detrimental to blood & short-tailed pythons by irritating the resipiratory tract. The use of humidifiers during the driest months helps to ensure that conditions are consistent all year long.
Aside from this, we don't go to great lengths to raise humidity in our pythons' enclosures. We don't spray them daily, nor do we provide particularly large water bowls that would allow for greater evaporation. Since the individual tubs in our rack systems maintain humidity at a level slightly higher than the room average, we don't feel that there's a need to increase this level under normal circumstances. When our pythons enter a shed cycle, we mist them to marginally increase the level of moisture in the enclosure. We don't shower the tubs, but lightly mist them with the sprayer attachment on our snake room hoses. Is this process absolutely necessary? No. There have been plenty of times where we haven't misted throughout the shed cycle, and our snakes shed just fine as a general rule. This method does help to ensure great sheds, and we enjoy the extra interaction with our pythons, as well as opening a tub to see a perfect, freshly-shed trophy with gleaming new skin.
Depending on the type of enclosure you choose for your blood or short-tailed python, you may not have to do much in the way creating additional humidity. A purpose-built cage with paper substrate, and a water bowl situated on the warmer side of the enclosure is usually sufficient for maintaining humidity levels. Most snake racks and cages make this easy to accomplish without too much effort. Other cages, like glass aquariums with screen tops, make humidity and temperature regulation difficult, we discourage this type of enclosure.
If you live in a very dry climate, a humidifier may be necessary to help boost the ambient humidity in your reptile room. Misting your python's cage is another alternative; handheld sprayers work well for this purpose and are available online, as well as through home improvement stores and gardening centers. The use of multiple layers of newspaper or kraft paper for substrate can promote higher localized humidity. Blood and short-tailed pythons like to sit under the layers of paper, and the snake's respiration will raise humidity between them. Shredded wood substrates, such as aspen or cypress, also retain moisture well and hold up to repeated misting better than paper substrate. Substrates of this nature require more maintenance, but may be worthwhile if your local climate is on the dry side.
On the other hand, if your python's cage stays very damp on a regular basis, you may need to consider additional ventilation. The most common sign of excessively high humidity is copious condensation build-up on the glass of a cage, or walls of a tub. In a tub, it's easy to melt holes for ventilation using a soldering iron, or drill them using a small-gauge drill bit. It can be more difficult to retrofit snake cages with extra ventilation, so we recommend ordering extra vents and vent covers when you first buy your cage if you have this option. It's much easier to close extra vents than it is to install or cut new ones, unless you are experienced with power tools.
While we do not use stand-alone hygrometers for measuring humidity, some of our digital indoor/outdoor thermometers have this feature. If you choose to purchase a hygrometer be aware that discount units are often inaccurate or calibrated incorrectly. One method for testing the calibration of your hygrometer is known as the "salt test", and is frequently used among cigar aficionados when setting up a humidor. To salt-test your hygrometer, you'll need a Ziploc bag or clear, airtight container, a bottle cap (one from a 20-oz soda bottle works great), table salt, water and your hygrometer.
Step 1: Fill the bottle cap 3/4 full of table salt.
Step 2: Add enough water to the salt to saturate it, but not so much that it is soupy. You basically want a cap full of wet salt, but not so much water that the salt dissolves.
Step 3: Place the bottle cap & your hygrometer into the bag (or clear container), and leave it for a minimum of 6 hours.
Step 4: After 6 hours, check the reading on your hygrometer. It should read 75% RH. Whatever % your hygrometer is off from 75% is amount your hygrometer should be recalibrated if you have this feature. If not, keep this margin of error in mind whenever referencing your hygrometer.
Alternatively, NIST-certified hygrometer models are available from various online vendors. They're more expensive, but much more accurate for gauging humidity. Ultimately, we don't consider hygrometers among our must-have, can't-live-without husbandry tools. It's nice to have one on hand for reference, but the overall health of our snakes and the consistency and quality of their sheds is a better indicator of proper humidity. Developing a good feel for correct humidity and optimal conditions will benefit a herpetoculturist more than than fussing with inaccurate hygrometers.
Food for Thought
So as it turns out, proper humidity for blood and short-tailed pythons is nowhere near the rocket science that some keepers have indicated in the past. As with many aspects of general reptile husbandry, it is simply a matter of understanding a snake's needs and tolerances, and creating conditions in an acceptable range to meet those needs.
Hopefully this section has debunked some common myths regarding blood python husbandry and humidity. Next, let's review various methods for creating hiding spots in your short-tailed python's enclosure.