“I have never been called to attend a case of Gila monster bite, and I don’t want to be. I think a man who is fool enough to get bitten by a Gila monster ought to die. The creature is so sluggish and slow of movement that the victim of its bite is compelled to help largely in order to get bitten.”
— Dr. Ward, Arizona Graphic, September 23, 1899
The Gila monster (Heloderma suspectum, ‘studded skin, suspected’ – of being poisonous) is the only venomous lizard native to the United States. It lives in Arizona, the southern desert regions of California, Nevada, Utah and New Mexico.
The word ‘Gila’ comes from the Gila River and the Gila River Basin. In the language of the Yuman people, Gila means ‘salty’ and is pronounced ‘hee-la.’
This “monster” has been the victim of many exaggerated myths and misconceptions. The Apaches believed its breath could kill a man, and the Tohono O’Odham and the Pima believed it possessed a spiritual power that could cause sickness. But the Seri and the Yaqui believed the Gila monster’s hide had healing properties. Early white settlers believed that its ‘fetid’ breath was toxic, and being bitten by one would kill an adult human.
Gila monster venom is very toxic, but its delivery system is designed to immobilize very small prey, so too little venom is produced to kill a healthy adult human, and their sluggish nature makes them not much of a threat to people. After Scientific American printed an article that repeated the “evidence” of the Gila Monster’s “toxic” breath in 1890, Dr. George Goodfellow of Tombstone, Arizona, decided to study actual Gila monster specimens. He paid local residents $5.00 for each Gila monster they could capture and bring to him. In 1891, Goodfellow deliberately provoked one of his captive lizards to bite him on his finger. The bite made him ill and he spent the next five days in bed, but he completely recovered.
When Scientific American ran another ill-founded report on the lizard’s ability to kill people, Dr. Goodfellow wrote in reply and described his own studies and personal experience. His articles about his research were later published by Scientific American and Southern California Practitioner.
Recently, medical science has analyzed the constituents of the Gila monster’s venom and saliva, and used them to develop synthetic versions of a protein, exendin-4, now used in a drug (marketed as Byetta) for the management of type 2 diabetes. They have also derived ‘Gilatide’ from exendin-4, which has shown promise in reversing memory loss in mice. Several companies are now researching its possible use in the treatment of Alzheimer’s, schizophrenia and ADHD.
While the movement of their bodies is very ponderous, Gila monsters are able to swing their heads sideways quite rapidly, and their jaws hold on powerfully and painfully. If a human is bitten, they may have to fully submerge the attacking lizard in water to break free – something often not readily available in its desert habitat.
Gila monsters spend 90% of their time underground in burrows or rocky shelters, and hibernate from November to January or February. They eat only 5 to 10 times a year in the wild, gorging themselves. They eat small mammals and birds, frogs, insects, other lizards and carrion, but primarily feed on bird and reptile eggs. They are able to climb trees and cactus. Their sense of smell is extremely acute to enable them to locate prey. They are in turn the prey of coyotes and raptors.
Gila monster populations are declining – their current Conservation Status is “Near Threatened,” and Arizona lists them as a protected species.
These lizards, almost unchanged since prehistoric times, are turning out to be desirable neighbors, making valuable contributions to medical science. Their myth is worse than their bite – but don’t tempt one.
- National Geographic: http://animals.nationalgeographic.com/animals/reptiles/gila-monster/
- National Zoo: https://nationalzoo.si.edu/Animals/ReptilesAmphibians/Facts/FactSheets/Gilamonster.cfm
- Arizona-Sonora Desert Museum: https://www.desertmuseum.org/kids/oz/long-fact-sheets/Gila%20Monster.php
- Wikipedia: https://en.wikipedia.org/wiki/Gila_monster