Asio Husbandry

By Jeff Judd

This is a large, hardy species of Horned Lizard (HL) that does well in captivity. It has a good appetite and thrives on a varied diet. These are very sociable Horned Lizards, interacting to each other with head bobs, arm waves, and tail wags. They are aware of their surroundings, and can recognize humans as a food source; they will watch in anticipation as food is being offered, and will eat from your hand.


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.