Reptiles require curated environments in order to thrive. From the temperature to the humidity, it can be a challenge to get everything right! Without proper humidity, an exotic pet might suffer from shed problems, respiratory infections, or even difficulty passing stool or eggs.
The good news is that there are plenty of options for both decreasing and increasing humidity. By carefully adjusting an enclosure and using an accurate hygrometer to measure humidity, any keeper can get their numbers to that sweet spot for optimal reptile health. Here are some suggestions!
Increasing Humidity
For most keepers, humidity challenges arise from moisture that gradually decreases over time, leaving their exotics drier than they should be. Some options for boosting humidity depending on the enclosure type and species include:
Misting systems
For enclosures that require higher levels of humidity, misting systems can be a powerful choice. These sprayers are connected to a programmable pump that goes off on a schedule set by the owner. Example misting schedules include “30 seconds every four hours” or “one minute every eight hours.” This allows for a high level of customization; misting for longer can produce very damp or even muddy substrate, while a brief mist on a frequently repeating cycle can keep humidity consistent without making the substrate too moist. For many keepers, misting systems are the gold standard for maintaining humidity.
However, there are a few important considerations when it comes to misting systems. First, the reservoir. Every misting configuration will require a reservoir in which to store the water the pump draws (and then ejects through the nozzles). For some people, having a bucket near an enclosure is too much of a hassle.
Another challenge is water sourcing; if keepers use regular tap water, it may contain too much mineral content, which can clog the spray heads over time. This can be avoided by replacing the heads from time to time or using distilled water. Finally, misting systems require the nozzles to be installed inside the enclosure—which means that there will be a small hole or opening somewhere for the tube that supplies water. This can be difficult to create for keepers without the proper tools, or it could provide an escape point for the enclosure’s inhabitants.
Foggers
Like misting systems, foggers inject moisture directly into the air of an enclosure. The difference is that rather than projecting water in the form of droplets, foggers produce, well, fog. This is a gentler means of adding moisture and can target more of the enclosure, because the fog blankets the entire space rather than drenching specific areas like a misting system might.
However, foggers too have their own disadvantages. The larger, less protected tubing is more susceptible to bacterial buildup, which can infiltrate a reptile’s lungs as they breathe the fog. If foggers run consistently, animals have few chances to escape if they want something drier—and since fog collects near the bottom of the enclosure, a terrestrial animal might not enjoy the experience. Foggers also tend to have much smaller reservoirs, which require filling more often.
Substrate
The substrate in an enclosure can play a big role in how much moisture is retained. Blends such as soil and sphagnum tend to hold more humidity than mulch-based substrates like cypress. By adding some water to the substrate and turning it consistently, keepers can provide a moist surface for reptiles that need it. This is one of the easiest approaches to keeping humidity up.
Conversely, using substrate as a means to control humidity can pose some risks. If things are too damp, the substrate can become boggy or even moldy. Reptiles that cannot escape a moist substrate may develop scale rot, and undesirable pests such as fruit flies can begin to proliferate. Still, the substrate is one of the first changes to consider when trying to boost humidity.
Water bowl
In some cases, a simple change can make a big difference. Simply moving the location of the reptile’s water bowl from the cool side to the warm side can provide a slight shift in humidity as the water evaporates from the heat.
Of course, the biggest risk with this option is that the animal will run out of water sooner because more of it is being converted into airborne water particles. Additionally, some reptiles might not like the experience of drinking heated water.
Sealing
Even if a keeper has worked hard to add a misting system, great moisture-retaining substrate, and more, their efforts will mean little if the humidity is escaping the enclosure as fast as it’s entering. Seal an enclosure to hold the water vapor inside. Weather stripping, silicone sealant, or even blocking the top of a mesh enclosure might be all it takes. Aluminum tape is a common option for those who need to seal up mesh, as it’s easy to apply and remove as needed.
However, keep in mind that an animal still needs to breathe! Maintain some ventilation and keep air flowing to avoid mold growth and stagnation. A small fan meant to cool the inside of a computer is a great choice that won’t suck too much humidity from the environment.
Decreasing Humidity
While the majority of keepers face the challenge of not enough humidity, some contend with the opposite problem: too much moisture. For desert-dwelling species and those in arid climates, high humidity can be a recipe for respiratory infections and more. To decrease humidity in an enclosure, consider:
Heating
The heat generated from certain fixtures can help to remove moisture from the air. For instance, ceramic heat emitters are notorious for drying out enclosures and can be used to both regulate temperature and reduce humidity without adding unnecessary light overnight.
However, the fixtures that are best at decreasing humidity (including CHEs) often do so because their hot surfaces interact with the water particles. This can also cause burns if reptiles come into contact, which means that enclosures often need some sort of barrier to use such heat sources. Installing this barrier (e.g., a light cage) may not be something everyone has the skill to do.
Ventilation
Just as ventilation can trap moisture inside to increase humidity, it can also release moisture that builds up in the enclosure. Consider widening vents or adding additional vents—just be sure the animal cannot escape through them!
One of the main challenges with increasing venting is that heat escapes alongside the humidity. Thus, it can be helpful to add vents near the bottom of an enclosure, as heat rises but moisture is highest near the floor.
Substrate
Mixed substrates such as soil can hold a lot of moisture, but they are not the only option. Sand (meant for human sandboxes, not calcium sand) can decrease humidity, as can other substrates such as aspen.
The biggest issue with using substrate as a mechanism for decreasing humidity is the particles produced. For instance, dried dirt can become dusty during activity, which can irritate an animal’s eyes and nose. Choose options according to your species’ activity habits and behaviors, such as burrowing or digging.