We’re the ones with language, so we have the power to call one of our fellow vertebrates a monster. As lizards go, the Gila monster is unusually clunky, chunky, and large—not a lissome tropical creature like a gecko or chameleon. It’s not pretty, and it is venomous, a trait that inevitably complicates any relationship. Still, loathing the creature is irrational; being careful around it is not.
North America’s largest lizard gets the first part of its name from the Gila River, which runs through Arizona and New Mexico. Its habitat is the desert scrub and dry foothills of the Sonoran, Chihuahuan, and Mojave deserts. The creature is the subject of dozens of dread-inducing bits of folklore that are, at best, unverifiable. (Unlucky male camper in the desert wakes up to find a Gila monster chewing on some tender body part. Lizard spits venom in someone’s eye. Lizard springs several feet in the air to attack. Parachutist lands on lizard. Lizard’s foul breath can kill you.)
The creature’s lumbering form and sinister look play a part in popular culture. In The Treasure of Sierra Madre, for example, a Gila monster is part of a suspenseful ordeal for the character played by Humphrey Bogart. In Meet Me at the Morgue, a 1953 mystery by Ross MacDonald (a writer as good as Raymond Chandler), a sullen blonde says of her suitor, “Big offers he makes. Mink coat, a new car, a trip to Honolulu. I told him I’d sooner go with a Gila monster.” As part of the 1950s trend for enlarging animals to make them scarier, the creature is the subject of a 1959 B movie, The Giant Gila Monster. First victims? Necking teenagers.
Herpetologists, bless them, find the 2-foot-long, lumbering lizard fascinating and beautiful. Its body has bands of black alternating with the colors of an Arizona sunset –pink, buff, or orange. They hope that more knowledge will lead to less detestation, perhaps grudging respect. (One unexpected Gila monster fact is that a research scientist at a Bronx Veterans Affairs hospital found in the 1990s that something in Gila monster venom lowers plasma glucose to normal range in people with Type 2 diabetes. A synthesized version is now an ingredient in the widely used diabetes drug Byetta.)
Though the Gila monster is shy, and you should consider yourself lucky if you see one in the desert, there is certainly reason to be careful in its presence. Its bite is extremely painful, though very rarely fatal. Of the 5,000 or so known lizard species, the Gila monster (Heloderma suspectum) is among the few that are venomous. Another is its neighbor to the south, the Mexican beaded lizard (Heloderma horridum). (Note: “Beaded lizard” is a much better, less prejudicial choice for a name than “monster.” In both The Treasure of the Sierra Madre and The Giant Gila Monster, the lizard shown in the films is called a Gila monster but is actually a Mexican beaded lizard.) A few years ago, Australian researchers proposed that Indonesia’s infamous Komodo dragon could also deliver venom. (It was previously believed the dragon’s mouth was so full of muck that the victim died of a bacterial infection.)
The lizard’s species name comes from the Greek helos for stud, as in the head of a nail, derma for skin. The suspectum because the man who named it—paleontologist E.D. Cope, in 1869—at first only suspected that the lizard was venomous. It took another half-century to confirm it. With their studs they’re well armored, but a determined coyote can still rip one apart, and free-ranging cats often kill immature Gila monsters. A Gila monster can live up to 28 years; the most common cause of death, as more of the desert is paved, is being run over by a car. With a nonautomotive predator, the lizard’s first line of defense is to retreat. If cornered, it exhibits a repertoire of warning signals, including hissing and opening its mouth wide.
The nail-head look comes from osteoderms, bony beads embedded in the skin. Jan Johnson, an Arizona-Sonora Desert Museum curator who cares for 20 Gila monsters, says their hide feels like an exaggerated basketball. An X-ray shows, in addition to the usual spine and leg bones, an array of polka dots.
Careless handling, which Johnson does not engage in, is the usual cause of bites. The vast majority of verifiable recorded bites (about 150 in the past 60 years) are on the finger or hand, delivered by a pet whose apparent passivity lulled its owner into handling the creature, or by a wild Gila monster avoiding capture. (Collecting Gila monsters in the wild is against the law.) Some of the bites occurred during a demonstration in a classroom or lecture, which has to have been deeply embarrassing as well as painful. Inebriation is often involved. There’s a verified story of a man in a bar bitten while playing a kind of Russian roulette by reptile, repeatedly sticking a finger into the animal’s mouth.
The last recorded fatality was in Casa Grande, Ariz., in 1930. As reported in the Arizona Republic, “Tom Reap, 62 years old, proprietor of the Moore pool hall, died at 12:20 o’clock this noon in the Casa Grande hospital, two hours after he had been bitten by a Gila monster.” The story continues with useful information about what not to do with a venomous lizard. “Mr. Reap was playing with the animal in the pool hall when he was bitten. The animal had been brought into the hall by one of the patrons and several were standing around looking it over and discussing it when Mr. Reap appeared. He began tapping it on the nose, witnesses said, and upon being cautioned replied: `Oh, it wouldn’t hurt you even if it did bite.’ ”
Reportedly it took a helpful pool hall patron five minutes, using a pair of pliers, to detach the lizard from Mr. Reap.