Venomous Lizards of North America: The Gila Monster

The Gila monster is named for the Gila River Basin.
The Gila monster is named for the Gila River Basin.

Going by the scientific name Heloderma suspectum, this is a species of lizard which is venomous, found in Mexico’s northwestern state of Sonora and to the southwestern region of the US. There are only two toxic species of lizards in North America, the other one being the Mexican beaded lizard which is the Gila’s close relative. However, in the United States, the Gila monster is the only venomous lizard.

4. Physical Description

Gila monster is typically slow-moving and heavy, measuring as long as 2 feet, and weighing approximately 1.8 kilograms. It is named Gila, after Gila River Basin where it once used to be in plenty. Gila River is found in New Mexico and Arizona. A Gila monster is heavy-bodied, with osteoderms (bead-like scales) which are black and yellow or pink and orange scales that are all over their body except the underbelly. They have broad necks and heads with their eyes being black and having round pupils. Their forelegs are strong and have claws that are appropriate for digging, with all their four feet being wide and having sharp claws.

3. Habitat and Range

This lizard can be found in deserts, scrublands, thickets, oak woodlands, burrows, or even under rocks. In short, they are located in any place that has ready access to moisture. They have been observed to have a liking towards water bodies, such that after a summer rain they immerse themselves in water puddles. On the otherhand, they avoid any open area or a flat land as well as farms. They are found in Mexico and the Southwestern United States. They have been identified in places like Nevada, New Mexico, some parts of California, Arizona, and Sonora.

2. Diet

The Gila monster is carnivorous. This means they eat meat, but one disadvantage to their physique is that they are so slow. Due to this, they are always on the lookout for easy prey, like eggs or newborn mammals. Gila monsters do not even chew their food and can swallow whole eggs. They also eat rodents, frogs, smaller lizards, insects, small birds, mammals, carrion, and worms. According to research carried out by the San Diego Zoo, a Gila monster can eat as much as a third of its weight in one meal. However, they can go for months without eating as they store fat in their tails.

1. Behavior

The Gila has a very strong sense of smell. It uses this sense to find prey, even eggs hidden 15cm deep. It also eats infrequently, at most ten times a year. It is also able to climb a tree or a cactus looking for eggs. Small prey is eaten alive. Despite being venomous, its venom is not fatal to human beings. Due to its slow movement, the animal is not a threat. They spend 95% of their lifetime in their homes and the other 5% is spent looking for prey and sunbathing.


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