Terrarium: 

GHLs should be housed in a glass terrarium. Overall, it should be long and wide but not very tall. Shallow tanks allow good ventilation and prevent heat from building up. The top of the substrate to the top of the terrarium should measure around 12 inches. The substrate level can be raised to accommodate a taller tank. The length and width needed depends on the number of GHLs that will be housed. However, the bare minimum for one or two adults should be 36" long x 18" wide.

Benefits of Large Tank: :

No terrarium is too large. Generally, the bigger the terrarium is, the better. With adequate space, intense lighting can be provided them, as well as a wider range of temperatures for GHLs to properly maintain their preferred body temps. GHLs will be able to properly feed, and exhibit more natural behaviors. Also, you can create a more realistic landscape that will better resemble their natural environment.

What to add: :

The bottom of the terrarium should be covered with three to six inches of sand. The sand should consist of various sized particles. Giant Horned Lizards purposely ingest specific sizes of these particles to aid in digestion. Rocks large enough for the GHLs to bask on should be placed under the heat lamp to provide basking sites. The cool side of the terrarium should contain plants or branches to provide areas for climbing. Suitable plants include many spineless cactus, succulents, palms, grasses, and non-toxic houseplants. Giant HLs are semi-arboreal, and during periods of inactivity, they will climb onto the plants or dead branches, or seek shelter under half-cut tree bark, cactus hollows, or sturdy rock formations.

Lighting:

The 160-watt or 250-watt mercury vapor heat lamps specifically designed for reptiles work very well for GHLs. They provide adequate levels of UV radiation as well as produce heat, which are both essential to keep GHLs healthy long term. Fluorescent lighting can be added if additional light is desired. The lights should be turned on and off by a 24 hour timer. They should be set to come on 13 hours a day May, June, July and August, 11 hours a day March, April, September and October, and then 10 hours a day November, December, January and February.

Temperature:

The terrarium should be placed in a room that stays between 65 and 75 º F year round. The heat lamp should be placed at one end of the terrarium while the other end remains unheated. The height of the lamp should be adjusted so that directly beneath the bulb the temperature is around 115 º F after the bulb has been on for an hour. This will provide a range of temperatures allowing the HLs to maintain their preferred temperature. No additional heating devices are needed after the lamp turns off, so the night temperatures should be falling between 65 and 75 º F.

Diet and Nutrition:

Giant Horned Lizards should be fed daily. They should be fed in the morning, or the late afternoon when they are most active. If they are fed in the morning, they should be allowed to warm up for about an hour beforehand. The insects should be placed in the same area of the terrarium at each feeding, because the Giant Horned Lizards will recognize a feeding area and look for food there. An individual’s appetite depends on its size, the time of year, and stress level. Generally, it is best to continue to feed the HL until it has no more interest in food.

Feeding:

In captivity, ants, crickets, or roaches should make up most of the diet with the occasional mealworms and waxworms. All of these insects are available commercially. Make sure the insects are from a clean source, otherwise they can harbor disease, which can be passed onto the GHLs. Crickets, roaches, and mealworms should be fed baby cereal and carrots before they are fed to the GHLs. The size of the insects is the most important aspect of feeding; they should be no longer than the width of the GHLs head. Feeding your Horned Lizards large insects can cause them to regurgitate it the next day, become very sick, or die.

Ants:

Ants (Pogonomyrmrex barbatus and Pogonomyrmrex rugosus) should be included daily. The ants available commercially from the genus pogonomyrmrex are eagerly accepted by GHLs. They should be kept in a large jar with a lid that has very small holes drilled into it. It's important to only put 3-5 ants in the tank at a time. Dumping large numbers in will cause the GHLs to panic, often resulting in the ants biting or stinging them. Immediately remove any GHLs, then the ants if this happens. If an ant latches on with its pinchers, it must be removed by crushing its head with tweezers then slowly pulling it off. Offer ants until the HL stops eating or showing interest. Remove any that are not eaten with forceps or large tweezers. 

Other Insects:

Crickets (Acheta domestica) and roaches (Nauphoeta cinerea) can be offered every other day. They come in many sizes, and do well with both hatchling and adult GHLs. They can easily be gut loaded and coated with vitamin and mineral supplements. However, crickets can be difficult to catch unless their hind legs are removed. Mealworms can be offered once or twice a week. They are difficult to digest. The number offered needs to be closely monitored. No more than 3 or 4 should be offered at one feeding. The freshly shed mealworms are best. These are white in coloring, and should be fed to Giant Horned Lizars when they are available. Waxworms are large and high in fat, which may be harder to digest in large numbers. No more than one or two should be offered to adults, once a week.

Supplements:

Giant Horned Lizards should receive a good reptile vitamin supplement and a good reptile mineral supplement twice a week. They are sold separately, so they must be mixed together. Add equal amounts of both in a jar, then put enough of either the crickets or roaches in for one feeding. You should shake the jar until the insects are coated with the supplements, then feed them to your Horned Lizards.

Water & Humidity:

May through October it rains very frequently in areas inhabited by GHLs. During this time, the whole terrarium should be misted twice a week with a hand sprayer. The substrate should be dampened, but not too wet and should dry out between waterings. The humidity should be kept between forty and seventy percent. Thoroughly mist the head and nostril area of the GHL until you notice that it is drinking water during each misting. November-April the terrarium should be kept dry. If live plants are used in the setup they can be watered by lightly misting the substrate around their base. The humidity should stay below 40 percent. Water should only be given to the Giant Horned Lizards once a month during this time.