Gila Monster Facts

The Gila Monster (Heloderma suspectum) is a unique venomous lizard only found in southwestern U.S. and northwestern Mexico. Gila monsters’ habitat is limited to the Mojave, Sonoran, and Chihuahuan deserts. These monster lizards have bright yellow, orange, or pink and black markings along their bead-like scales. They are one of two venomous lizards found in Northern America. Unlike snakes, which inject venom, Gila monster venom is secreted and distributed when it bites down with its teeth and begins a chewing motion thus injecting neurotoxic venom into the wound. As you can imagine these bites are extremely painful to humans, but there has never been a reported human death attributed to Gila monster poison.  

Quick Facts About Gila Monsters: Q&A

  • What are Gila Monsters? Gila monsters are the largest lizards that are native to the United States. They have distinctive markings, are desert dwellers, eat small birds and mammals and it is said that they can consume all the calories they need for a year in just three or four large meals. Owing to their size and venomous nature, they loom large in lizard lore and human imaginations, but are not so monstrous in real life.
  • How big is a Gila monster? While Gila monster hatchlings measure a mere 6 inches at birth, fully grown Gila monsters can measure nearly 2 feet (approximately 22 inches or so) in length.
  • Are Gila monsters venomous? Gila monsters are one of two venomous lizards in the U.S. It uses its powerful teeth to wound its prey and then grind its neurotoxin into the womb. While these bites can be very painful to humans, we don’t tend to be Gila monsters’ preferred prey, and there’s never been a human death caused by Gila monster venom.
  • Are Gila monsters poisonous? Technically no. And it all comes down to the difference between venom and poison. Chemically speaking, venom and poison are dissimilar—poison molecules are small, allowing them to pass through skin, be inhaled or ingested. Whereas venom molecules are larger, necessitating a bite, puncture or other type of injection site to enter the body. That makes a Gila monster venomous, but not poisonous.

Nevada Gila monsters are well adapted to the harsh environment of the Mojave. Among many interesting facts about Gila monsters is that they spend up to 95% of their time in underground burrows. They can survive months between meals by storing fat in their robust tails. Gila monsters in Nevada leave their burrows only to feed and occasionally to bask in the sun. They are master scavengers and can subsist on a diet consisting primarily of eggs stolen from nests, newborn mammals, carrion, frogs, and insects that reside in Gila monster habitat. They hunt through their sense of taste and smell. Using powerful jaws and biting motion they release a powerful neurotoxin into their prey’s bloodstream that disrupts the nervous system. Gila monster venom does not just help these monster lizards hunt, it also aids them in defending themselves when disturbed by humans or predators. 

Another of the facts about Gila monsters is that they have very few natural predators, yet as a species they are not flourishing. Destruction of Gila monster habitat is the largest threat to this fascinating species of monster lizards. The habitat of Gila monsters is under pressure due to human development, overgrazing of livestock, truck farming and over-planting. The Gila monster is considered near-threatened according to the Endangered Species Act.