Gila Monsters

Gila monsters (pronounced hee-la monsters), or Heloderma suspectum, are large, slow-moving venomous lizards native to the southwestern United States and northwestern Mexico. They are one of only two venomous lizard species in the world, along with the Mexican beaded lizard. 

These reptiles are protected by state law in many areas and are most commonly found in the Gila River Basin, desert canyons, rocky foothills and even some residential areas. 

Where gila monsters live and how they spend most of their time 

Gila monsters spend up to 95 percent of their time underground. They come out for just a few weeks a year—typically from early March through mid-May during the day, then switch to being active at night during the summer monsoon season.

How to identify a gila monster: Size, color and features

These lizards are easily recognized by their unique features:

• Stocky, heavy-bodied with grooved teeth for delivering venom
• Up to 24 inches long and weighing as much as 2 pounds (about 8% of their body weight is stored in fat reserves in their tails)
• Bold black markings over cream, pink, yellow or orange skin
• Distinct black patches around the mouth and eyes
• Prefer shelter under rocks or pack rat nests to avoid the heat

Gila monsters share their habitat with birds, snakes and other lizards, but they are slow and generally avoid confrontation unless threatened. 

Gila monster venom and bite symptoms

Gila monster venom is delivered through grooves in their teeth—not injected like a snake’s bite. Though rarely fatal, a bite is serious and painful. Symptoms include:

• Severe pain within 30 seconds
• Swelling, weakness and dizziness
• Nausea, chills or even shock

These lizards often hold on tightly when they bite, making removal difficult. The longer they stay attached, the more venom is delivered.

What to do if you are bitten by a gila monster

If a Gila monster bites you:

1. Do not wait for symptoms.
2. Call the Poison Help line immediately at (800) 222-1222.
3. Go to the nearest emergency medical facility.
4. Do not try to cut the wound or suck out the venom.
5. If the lizard does not release on its own, you may have to carefully pull it off.

When to call Poison Control about gila monsters

If you have questions about Gila monsters or other venomous animals in North America, call the Arizona Poison and Drug Information Center at (602) 253-3334 or contact your local poison center at (800) 222-1222.