For Leopard Geckos, humid hides – also known as moist hides – are an essential part of a habitat. Humid hides are essentially just caves with high humidity which are needed for self-regulation and shedding.
They can retreat into it if they need some extra humidity, especially when they are shedding. All you need to provide a humid hide is a cave-like structure (usually made from plastic), a moisture-retaining substrate (usually Sphagnum moss), and occasionally, a spray bottle to mist the cave or substrate.
Why Leopard Geckos need a humid hide
Humid hides are critical for Leopard Gecko for two reasons: keeping hydrated and for shedding.
Hydration
Leopard Geckos, like many reptiles, are cold-blooded, and rely on their environment for regulating both temperature and hydration. Much of a Leo’s hydration actually comes from food and environment, and only a small part is from directly drinking water. They may only actually drink once every few days with adequate moisture supply from the environment and feeder insects.
The key is self-regulation: just like Leopard Geckos need the option to drink if needed, they must have the option to retreat into a moist cave if they need more moisture in their skin and body.
Shedding
During shedding, the old skin is slowly separated from the new skin, forcing it to dry out while the new skin is developed. Once ready, in between the two layers of skin, a layer of lymph fluid is built up to further separate the old skin, so it can be more easily pulled off by the gecko.
To make this process easier, adequate humidity and moisture are needed. Without it, the old skin will be difficult to pull off, which can cause it to get stuck. At worst, this stuck skin can inhibit blood flow to limbs or digits, which can cause serious injury.
That’s why Leopard Geckos naturally seek humid hides or water during shedding.
Beyond making sure that there is a moist hide in their enclosure and a water dish large enough to sit in (without drowning, of course), you can also occasionally mist the gecko during shedding – especially if it seems to struggle. A warm bath for 15-30 minutes can also help. However, the first priority should be to provide a cave with high moisture so the gecko can self-regulate as needed.
How to set up a humid hide
Now that you know exactly why you and your gecko need a humid hide, let’s get into setting one up. Luckily, setting up a moist hide is quite easy. All you need is a cave element (which you can build yourself – more on that later), a substrate to capture and retain moisture, and a good placement in the tank.
Choosing the cave element
For the cave, there are two main factors: The size of the cave and its ability to retain humidity.
As for the size, you should pick a cave that is about 2-3 times larger than your Leopard Gecko. But not 2-3 times longer than your gecko – that would be too much. Instead, the gecko should be able to turn around inside the cave, get comfortable. It should feel more like a queen-sized bed than like a coffin. A queen- or king-sized cave, if you will.
To make sure the cave retains humidity, make sure it’s not too large, the entrance is not too large (to keep circulation to a minimum), and the material is moisture-retaining. Wood, for example, is simply not a suitable humid hide material for this simple reason – it doesn’t retain moisture. Stacked rocks are also not suitable, as there is too much circulation.
For these reasons, it’s best to simply buy a reptile cave – there are plenty of great options available.
Make sure you get one that’s at least 8-10 inches long and 6+ inches wide. Smaller than that, and your gecko will barely fit. That’s why we always recommend going for a tank larger than the recommended 20 gallons – in those, you barely have enough space for elements like such a cave. You can check our recommended tanks here.
Choosing the substrate
The cave alone is not enough to retain humidity, though. In it, you will need a substrate that is moisture-friendly. If you are using a bio-active or similar substrate, it might be enough. If you are using a more artificial or inorganic substrate, like gravel, stone tiles, or a reptile mat, you will need a special substrate in this cave.
The most common option is Sphagnum moss – a type of moss that excels at holding moisture. Both living and dead Sphagnum moss can hold up to 26 times as much water as their dry weight (source). This makes it perfect as a “moisture tank”. Make sure to get Sphagnum moss, and not peat moss or Sphagnum peat moss. Peat moss is decomposed sphagnum with shorter fibers and a higher acid content. Also, get “long-fibered” Sphagnum moss if possible, and avoid milled moss. Zoo Med’s New Zealand Sphagnum Moss is a great option.
Another option is Coconut bedding. Make sure to buy a product that is soil-like, and not a bag of coconut shell pieces. These larger, harder shell pieces are not only bad at retaining moisture, but can be harmful to your gecko’s soft belly skin. However, if you buy the right coconut bedding, it’s a good option for a humid hide. Josh’s Frogs Coco Cradle Brick is such a product – safe for Leopard Geckos, and ideal for a humid hide.
A temporary solution is using paper towels. Make sure to replace them regularly, and ideally replace them with a proper substrate at some point. For a short-term improvised solution, though, it’s a safe choice.
Whatever substrate you choose, make sure to keep it moist, not wet. If necessary, especially when you first set it up, you will need to mist it gently with water. Do this gently to make sure the substrate doesn’t get completely wet. Otherwise, this can lead to too much humidity in the humid hide as well as becoming a breeding ground for bacteria.
Choosing the tank placement
Placing your new humid hide is simple: It needs to go on the warm side of the tank. The temperature inside the humid hide should be around 84-90°F (28-32°C). Make sure to occasionally check this with an infrared thermometer gun. If you don’t yet have a warm zone and a cool zone in your tank, read our guide on temperature management for Leopard Geckos.
Beyond that basic rule, I would also place the cave in a way that the entrance is visible to you. You should be able to easily check if your gecko is currently in the hide.
Also, I would place the cave toward the outer parts of the tank, away from the basking spot. Some leaves or other cover-providing terrain helps make your gecko feel safe and hidden – it’s called a hide for a good reason! Leopard Geckos have predators in the wild, and just because there are none in your home doesn’t mean that your gecko’s instincts get turned off. If they retreat, they like to feel safe by being hidden from plain sight, especially from above.
How to build a DIY humid hide
If you choose to build your own DIY humid hide for your Leopard Gecko, you have a few options. The main decision you have to make first is whether you are improvising a temporary replacement cave or building a proper hiding spot.
For a temporary DIY moist hide, many old plastic containers can work: From ice cream boxes to Tupperware boxes, anything big enough can work. However, make sure it can withstand the temperatures. Also look for food-quality, BPA-free plastic. The higher the quality, the lower the chance that it can degrade and harm your pet!
All you have to do is cut a hole that’s big enough for your gecko to easily crawl through, then smooth it out with sandpaper to make sure there are no rough edges or sharp corners. Finally, add paper towels inside as the bedding (or one of the other substrate options).
For a high-quality, long-term DIY humid cave, you can be a little more creative. Hobby shops have many options for sculpting and building structures – many of them will work for this project. Just make sure that at least the inside of the cave is completely non-porous. You could, for example, use a quality plastic dome as the cave, and on the outside, sculpt a natural-looking surface with any kind of foam, clay, or rocks.
However, keep in mind that it may take a few tries until you can build your own humid hide that works well and is comfortable for your gecko. Most likely, a pre-made reptile cave is going to be more cost-efficient than building your own. Additionally, if you buy from a trusted brand, you can rest assured that it is safe.