Gila Monsters of the Sonoran Desert…Closer to a Monster or a Mouse?

Gila Monster Large
Here we have pictured the famed Gila Monster, Heloderma suspectum.  It is the largest lizard native to the United States, yet at an average length of 10-12 inches including their tale, their moderate size alone is no reason to call them a monster.  Although remnants of Gila Monster scales have been found in Nevada that date back 8-10,000 years ago, the name Gila comes from the fact that they were once plentiful in the Gila river basin of New Mexico and Arizona (where this photo was taken).  These lizards are known to range from Southwestern Utah and New Mexico, throughout Arizona and all the way down to Sinaloa, Mexico.  So why the dramatic name?  Perhaps their Latin name will give us more clues as to why these creatures have been deemed monsters…a word that seems to conjure more fear than is justified for these plodding creatures.

Heloderma comes from the Ancient Greek words helos,meaning “the head of a nail or stud,” and derma, meaning “skin.”  Thus Heloderma means “studded skin.”  Which describes very accurately that the texture of their skin is studded in a stunning mosaic of tiny black and orangish bumps.  Is this why they are a monster?  What about Suspectum?  This part of their taxonomy comes from the paleontologist Edward Drinker Cope who while naming them suspected by the lizard’s grooved teeth that they might be poisonous.  Being named suspicious seems far better than the name their closest living relative the beaded lizard received, Heloderma horridum.  Yikes!

E.D. Cope’s suspicion was right.  The Gila Monster produces a venomous neurotoxin which is as toxic as that of the coral snake.  Thankfully our H. Suspectum only produces it in small quantities and does not have the musculature to forcibly inject the venom; therefore, its bites are not fatal to healthy human adults.  But beware because if they do get a hold of you, they will likely not let go unless you submerge them in water or use a knife to pry open their mouth!  Before we knew the effects of their venom through years of scientific observation and experimentation, the pioneers of the old west were mighty worried about this strange creature.  It is probably from stories of this time that we inherit the idea of the Gila “monster.”

In 1881 the newspaper in Tombstone reported the finding of a huge specimen: 27 inches long and 35 pounds!  The story in the Tombstone Epitaph read, “This is a monster, and no baby at that.”  At one point the settlers of the Old West thought the lizards breath was poisonous.  There were even a few erroneous stories ran in Scientific American that perpetuated murderous myths about the creature.  Luckily in the 1890s Dr. George Goodfellow of Tombstone began to research the effects of the Gila monster venom.  He finally provoked one to bite him on the finger to try it for himself.  Although it made him ill and he spent the next five days in bed, he recovered.  Thus, the venom is strong, but not deadly.  There have been no deaths reported since 1939 and before that it is likely the deaths attributed to the monster were from attempts to treat the bite.

The funny part of the scary hype about Gila monsters is that they are one of the slowest creatures in the desert.  They practically waddle.  This led a Dr. Ward to tell the Arizona Graphic in 1899 that, “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.”  To temper this seeming truth, the Apache also believed that its breath could kill a human, and the Pima and Tohono O’odham believed it had possessed a spiritual power that could cause sickness.  I don’t know about you but I don’t want a lizard to latch onto my finger causing excruciating pain and a feeling of sickness for days.  Either way you split it, this creature is probably closer to the mice that it consumes every now and then than to a monster, but these lizards command and deserve respect.  It’s best to give them plenty of space.

There is SO much more to share on the fascinating lives of Gila monsters that I hope there will be a part two to this blog post.  It is truly exciting to see them in the wild!  You might consider a visit to the Arizona desert, the namesake of these fascinating lizards, just to catch a glimpse.  You could either go for luck in the wild, or visit our amazing Arizona-Sonora Desert Museum where they have live specimens.  The Inns at El Rancho Merlita would love to host you on your desert adventures.  Check us out here!

All the best,

ERM Family

Road In



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