Lizards need housing that provides them with emotional and physical comfort. Emotional comfort means that the animal feels safe. Physical comfort means that the cage temperature and, to a lesser extent, humidity, are within the same range as your lizard’s origin.
Providing those aspects is easiest if you understand the type of lizard you have. Lizards fall into three basic groups: those large enough that few things bother them (like the komodo dragons), those that flee danger (like whiptails and iguanas) and those that prefer to hide from danger rather than flee (like leopard geckos and anoles).
Lizards that are too large to worry about predators are too large to be kept by a hobbyist, not to mention legally protected. Running lizards can use large-scale housing, something that gives them space to wander and to set up territories. But providing room-sized caging for a trio of 10-inch-long lizards is beyond the capabilities of most hobbyists.
Types and Sizes of Tanks
Most hobbyists utilize glass aquariums for terrariums, adding a screen top. For most lizards, a 20-gallon tank (24 inches long, 12 inches wide and 12 inches deep) provides ample space. For smaller lizards, you could use a 15-gallon or even a 10-gallon tank, but unless you’re talking about very, very small lizards like baby swifts, a 10-gallon tank is too small for protracted use.
The Importance of Temperature
For lizards, physical comfort generally comes down to temperature. They cannot function at what we consider a comfortable room temperature. Lizards, and indeed all reptiles, depend on warmth from an outside source to keep their bodies functioning. A lizard that is too cold literally cannot move and cannot even digest the food in its stomach. Pneumonia sets in almost immediately.
Although lizard species have specific temperature requirements, plan on keeping at least one end of the cage at a minimum of 80 degrees and to create a basking area with a temperature of about 95. Nighttime temperatures can be somewhat cooler.
You can raise the temperature in the basking area with a small spotlight, but this should be augmented by a heating pad. Place the pad under the same end of the tank as the basking light so that it can heat the area when the light is off at night. When just one end of the tank is heated, you create a thermal gradient, which means the lizard can select the temperature it wishes for its surroundings.
Lizards defend their territories. Since you’ve taken your lizard out of the wild, you probably cannot provide enough space for each lizard’s own territory. But you can make up for those space limitations – and give a place of concealment to a species that hides to avoid trouble – by providing visual barriers.
You can do this with vining plants (real or fake), short sections of limbs, pieces of bark or hide boxes. If your lizard can’t get away from a potential enemy, you (the ugly human) or another lizard, at least the “enemy” won’t be visible. Commercially-made hide boxes are readily available. Most are variations on a dark plastic box with an entrance hole. Ideally, you will provide several hide boxes, at least one per animal, and place the boxes at the cool and at the warm ends of the cage.
Your lizard needs water daily. This can be provided passively via a shallow dish of water or a dish equipped with a bubbler. Bubbler bowls are for those lizards that don’t drink still water. They are simply bowls that are attached by tubing to a small air pump.
You can also mist the plants and walls of the enclosure daily or every other day. Misting is used for arboreal lizards that don’t descend to ground level and for desert lizards that drink dew droplets. Mist one of the rock or corkbark pieces in the cage and one or two walls of the tank. Watch the lizard’s reaction; if it runs over to the misted area and laps one spot then another as if it’s very thirsty, mist again later when the droplets disappear. You want your lizard to be interested in drinking but not seriously dehydrated.
Some hobbyists use a drip bottle, a water-filled container with a small hole in the bottom that sits on top of the cage. The droplets of water ooze through the hole and splash down. A clean yogurt cup is large enough for most cages. The container can be placed over a plant, the water dish, a log or rock. Wash the container daily and rinse it carefully.
The Right Flooring
You’ll need to provide a substrate to serve as your tank’s flooring. Substrate can take several forms. At one end of the spectrum is the easy and cheap choice, paper towels or newspaper. For smaller lizards, paper towels are the better selection. These lizards are too light to rumple the towels, which are absorbent and easily changed when wet or soiled.
Newspaper may work for smaller to medium lizards. Newspaper is absorbent to a degree and tends to lie flat, but its slick surface affords no walking or running purchase for your lizard. Gravel works well, and can be readily cleaned by dumping it in a bucket and washing it with a hose.
Non-aromatic mulch is a good substrate choice. It’s moderately absorbent, provides a burrowing surface to give smaller lizards a feeling of security, provides good traction and gives a natural appearance to the cage. Along the same line as mulch but more expensive are substrates made from crushed walnut/pecan shells or compressed coconut fiber.
Newspaper makes another appearance here as a compacted/pelleted product that provides all the benefits of mulch and other loose substrates. One word of caution, though: lightweight pelted or granular substrates can easily be ingested with food. If you use these substrates, add a large flat rock or small tray atop the substrate as a feeding platform.
One-piece substrates like cage carpets look good, provide traction and are generally easy to wash. (Clean the sink afterward with a 1-10 bleach water solution). Any spilled food is easily picked up. On the down side, the carpets aren’t as absorbent as mulch or other loose substrates, and waste matter is very obvious.
A variety of climbing/clambering surfaces not only gives your lizard places to explore and to hide, but makes the cage more attractive. Because these items need to be anchored in the substrate, a cage with only a paper towel or newspaper substrate is limited to a water bowl and a hide box or two for décor. Cages with gravel or mulch substrate offer a lot more decorating options.
For desert lizards, you’ll need to keep the cage furniture to pieces of cholla cactus skeleton and rocks. Living plants, even xeric-adapted plants, tend to add moisture to an environment that is already enclosed. Die-hards can add cactus still planted in their pots.
For woodland/jungle species like geckos and iguanas, you can add pothos and dwarf sanseveria along with climbing limbs and vertical slabs of corkbark. Branches can be added but keep them at least 1.5 times the diameter of the lizard, so the branch can be securely grasped, and wedge the branches into place so they don’t slip.
Clean the tank whenever you can see feces or if the tank smells musty (The musty smell is generally the combination of lizard excreta and a too-moist cage, both of which are signs of carelessness on the part of the owner.)
If the substrate is paper, just remove it, and mist on cage cleaner. A mixture that’s one-third alcohol and two-thirds water, with a drop of two of dishwashing liquid, makes a good cleaner. Wipe the cage dry with paper towels and replace the paper substrate.
If you use a gravel or mulch substrate, you can just pick up the dried feces with a paper towel. Change out the substrate every month or so, misting and wiping the empty cage with the cage cleaner.