Gila Monster

Large orange and black lizard
Gila monsters are one of the heaviest reptiles found in Grand Canyon National Park.

Lynn Chamberlain, Utah Division of Wildlife Resources


Scientific Name

Heloderma suspectum



  • Distinct black and orange coloration covers their bodies in large blotches.
  • Large, thick bodied lizards, gila monsters can reach up to 22 inches (56 cm) in length and weigh over 5 lbs (2.3 kg).
  • The skin is covered with round, bead-like scales (the scientific name, heloderma, means "studded skin" in ancient Greek).


  • Gila monsters are found in northern Mexico and the southwest United States.
  • They live in deserts and arid scrublands, and prefer rocky areas where they can navigate between rocks without being seen.
  • Gila monsters are found in the desert areas at the far western edge of Grand Canyon National Park.


  • Gila monsters are one of only 2 venomous lizards in the world. It is believed that they use their venomous saliva for defense, rather than hunting.
  • Gila monsters are carnivores. Because they are slow moving, they use stealth to sneak up on their prey or feed on prey that cannot get away.
  • They use their forked tongue to detect scent particles in the air as they hunt rodents, lizards, bird eggs, and invertebrates.
  • Gila monsters are well adapted to a desert environment., and they adjust their behavior based on the weather. In the hottest temperature they are only active at dusk and dawn, but in cooler weather they hunt throughout the day.
  • In the winter, they live in desert tortoise burrows, and live off fat they have stored in their tails.
  • Gila monster venom is not fatal to healthy humans, but a bite can be very painful. Do not handle these unique reptiles.

More Information

Last updated: April 28, 2016

Park footer

Contact Info

Mailing Address:

PO Box 129
Grand Canyon, AZ 86023



Contact Us