May 2021 Update: Nest boxes and hopefully eggs soon!

Momma getting ready for the big day!

Though work and the other parts of my life have kept me from updating this blog on a regular basis, working with the Gilas has not slowed down. As of today my females are gravid and have gone through their pre egg-laying shed so oviposition is expected within the next week, according to my calculations.

Two of my females cages with privacy tint installed.

This year my nesting protocol has changed due to the failures (or, opportunities for learning) of last year. last year one of my females delayed egg laying by about 10 days which resulted in the death of six viable eggs. Not a very fun lesson but certainly an opportunity for improvement. I think last year the female did not have the proper secure nesting area and held her eggs until she could not hold them any longer. I also tried a new nesting material which did not work out very well as it did not hold moisture for very long. This year, things have changed.

To help increase privacy and to solve the humidity issue everything has been changed. To start, the entire cage has been converted to a nest box. This is to allow the females to continue to thermoregulate (though over lower temperatures) throughout this period. I have installed privacy tint on 1/2 of the cage as well as a large black hiding box to increase privacy. I also went back to good old sphagnum moss misted daily to help maintain moisture in the cage. The ultimate goal is to provide a secure area that matches conditions for positive egg growth. So far it appears to be working as the conditions in the cage mirror those in my incubator (see below screenshot from my SensorPush app).

Pretty close!

Will this ultimately work? We will know within two weeks. If all goes well my females will lay viable eggs this year. If not, I’m sure there will be a lesson learned and opportunity for improvement next year! Fingers crossed!

Great Gila article on

I always look for all things Gila on the internet and come across this fun and well-written article on of all places. Enjoy!

Don’t Call It a Monster

But be very cautious around the venomous, determined, lumbering Gila monster.

Constance CaseyApril 26, 20138:00 AM

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 Madreand 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.

Which brings us to the Gila monster’s venom delivery mode. The creature is loath to use its ultimate weapon, but once deployed the system is absolutely terrifying. The Gila monster is the pit bull of reptiles. Its short, sturdy skull with blunt, black snout is adapted to a long bite. (The shape works; it hasn’t changed much in the past 23 million years.) Venomous snakes by contrast have fragile skulls, built to conform to the shape of whatever they’re eating, often something bigger than they are. Snake venom is injected, hypodermic-style, through fangs in the front of the mouth, and it acts quickly. The point is to subdue prey before its thrashing injures the snake.

If you are so astoundingly foolish or unfortunate as to be bitten by a Gila monster, it will get a good grip and then chew; it can hold on for as long as 15 minutes. The grinding releases venom from glands into grooves in its sharply tipped teeth. (All venom, incidentally, is modified saliva.) Oddly and inefficiently, the two glands are located near the bottom teeth, and the poison must travel upward, presumably by capillary action.

The longer the bite, the more venom enters the victim’s body, via lacerations made by the teeth. One emergency medicine handbook provides “tips and tricks” for removing the animal. These include the following: Don’t pull or pry it off; that increases the possibility of leaving teeth in the wound. A flame under the jaw or immersion in water may work.

In addition, there’s this rather considerate advice: “Put the animal’s feet on the ground so it doesn’t fear falling.” And a particularly ominous note: “Always take special care to prevent reattachment of the animal to the victim or subsequent attachment to the person removing the animal.” Doctors are advised when cleaning the wound to make sure all the teeth are removed.

The effect of the venom, potent but not as damaging as a rattlesnake’s, is excruciating pain that has been described as a steady burning, like a spine embedded in the flesh, lasting up to 24 hours. There’s no commercially available antivenin; doctors treat pain and swelling and the most dangerous possible effect, a drastic lowering of blood pressure.

Gila monsters use their venom sparingly and primarily as defense against predators rather than to subdue prey. (Their fellows in using venom primarily for defense are the platypus and the stonefish.) Daniel D. Beck, author of Biology of Gila Monsters and Beaded Lizards, says he has often seen Gila monsters “delicately swallow” young cottontails without the chewing or pumping that’s displayed when they envenomate an enemy. The lizards’ favored foods are bird and reptile eggs, newborn small mammals, and bird nestlings—food sources that do not put up much of a fight. Eggs seem to be their favorite; the lizard splits the egg and, kittenlike, laps up the yolk. A Gila monster can eat one-third of its body mass at one sitting and survive on three good meals a year.

Because they don’t go out foraging often and they stay in a cool place in the summer, you’d be fortunate to see a Gila monster in the wild, Beck says. “You’d have to be a fool to be bitten,” says Beck, who has not suffered a bite. A Gila monster spends 95 percent of its time in a burrow, out of the sun, venturing out mostly in spring to find food and a mate.

Like everything that lives, Gila monsters are driven by hunger, fear, and the need to reproduce. What looks sinister and snakelike—the forked tongue flicking out every few seconds—is the lizard’s way of experiencing the world. The Gila monster is essentially tasting the air, picking up clues as to where there might be some quail eggs to eat, a likely mate, or a coyote to avoid. When the lizard’s tongue pulls back in, the two tips are inserted into little holes in the roof of the mouth. This delivers the captured odor particles to the Jacobson’s organ, named for 19th-century Danish anatomist Ludvig Levin Jacobson. Some of the chemical compounds bind to receptor molecules, sending messages to the lizard’s brain. Other reptiles have the Jacobson’s organ, as do some amphibians and mammals.

The Gila monster evolved such a keen sense of smell because food in an arid environment is widely distributed. The creature rarely runs, but it can trudge for miles. Most people’s impression of Gila monsters, from seeing overfed specimens in a zoo, is that they’re obese and lethargic. Smaller lizard species, in contrast, are in danger of being eaten and adapted by being well camouflaged or very fast. (And there’s their amazing ability to drop the tail when threatened. The severed tail continues to twitch, keeping a predator’s attention.)

The Gila monster does not give up its tail, which is as useful a camel’s hump for fat and water storage. In times of scarcity, the tail shrinks down to something like a ballpoint pen rather than the usual kielbasa sausage.

Low metabolism and frugal energy use are advantages in food-scarce regions. But recently it has been found that though they have a low metabolic rate, Gila monsters possess high aerobic capacity and surprising endurance.

Beck demonstrated this by putting a Gila monster on a rubber treadmill with a Dixie cup over its head. A tube from the cup sends the lizard’s exhalations to a gas analyzer and calculates the rate of oxygen consumption. How does a Gila monster respond to this gymlike activity? Some object, Beck says, but most keep on tramping “in a kind of trance. Into the Zen of being a lizard.”

In the wild, Beck tracks the lizards’ long routes by radio transmitters implanted surgically (with difficulty because of the studded skin). He and other scientists have found, by using radio telemetry, that a lizard is loyal to a couple of particular shelters. Sensibly, they find a south-facing haven in winter, one that’s cooler and moister in the summer.

Beck loves them, but when asked what a Gila monster’s life is like he has to say “dull.” They do spend most of their time doing nothing. However, from April to June, there is drama, ritual combat that’s a challenging endurance test. Two males meet in what is essentially a wrestling match, arching and flexing sumo-fashion. The contest, which can go on for hours, ends when one has forced his opponent to the ground and remains on top. Though equipped with venom and sharp claws, the males, sensibly, do not kill or wound each other. The loser walks away unscathed; the winner, having proved his fitness to reproduce, gets breeding territory or, better, a shelter with a female inside.

When a female has been won, the victorious male lies beside her and rubs his chin on her back and neck. If she accepts him, she raises her tail and the male moves his tail under hers, bringing their vents into contact. Copulation lasts from half an hour to an hour. Which brings us to the hemipenis. Like snakes and other lizards, a male Gila monster has a retractable penis that pops out like the finger of an inflatable glove, an advantage on rocky soil. Actually, he has two; they pop out together but only one at a time is used. The hemipenises are elongated tubular structures stored in the tail, decorated with tubercles in a fashion Beck calls “flounced ornamentation.”

In July or August, the female lays one to 12 eggs in an underground hole. Incubation may last nearly 10 months, and the 4-inch-long young may not emerge until a year after insemination.

For millions of years, human beings figured very little in Gila monsters’ quiet lizard lives. Then we began building deep into the desert. One of Beck’s formerly prime locations for studying Gila monsters is St. George, Utah, now the site of a fast-growing retirement community. (Someone in one of those newly built units probably has a bottle of Byetta in the medicine cabinet.) Desert houses, surrounded by irrigated land, provide attractively moist, shady environments for the bolder lizards, which is beginning to create a problem. Every year dozens of Gila monsters (and thousands of rattlesnakes) are removed from properties in Phoenix and Tucson. From the homeowner’s point of view, the lizard is large and scary—and protected by state law; killing it is not a legal option. From the herpetologists’ point of view, there are too many Gila monsters run over by cars and too little unpaved, unspoiled desert habitat left for them.

Beck, who grew up exploring deserts in his native Utah, allows that the Gila monster doesn’t seem beautiful to most people, “But they’re an indication that we live in a beautiful place. Lose them and the beauty is diminished.”

The Honeymoon Suite

Which one is the boy and which is the girl? Guess first, then answer below.

My 2020 Gila monster season is off and running. After reviewing my data and re-reading my Gila books, I was going to wait until after April 1 this year to pair the Gilas as that is when the magic happened (and seems to be for others as well). With the Shelter-in-Place order in full effect I got bored and but them together last weekend, and guess what? No activity yet. What I have found interesting is that the Gilas seem to remember each other from last year and there was no fighting between the pairs (females bit males for being too pushy). This year they are much more chill, and are spending time together the hide boxes. I have been checking in at night to see what is going on and while both Gilas are active, copulation has not yet been observed. Being a Nervous Nelly, I am concerned that they will not breed this year but will hold my real worry for late April

Belle & Pink Floyd (banded Gila monsters) resting sweetly in their hide cave

To me, the real question is could Gila monsters mate for life? I’ve read that in the wild males go back to the same shelters where they have previously copulated and in my observations females certainly do prefer some males over others. The way they rest together and spend time with each other makes this is an interesting avenue to explore. Some breeders swap different females in male cages and have great success, but I am going to try leaving known pairs together to see how things go. I can see why having one pair of Gilas could be difficult to breed and that groups (3.3 or greater) are suggested.

Winston & Heather (reticulated Gila monsters) snooze the day away

As with all things, time will tell. New observations, and hopefully some activity, will be reported here. Stay tuned..

Answer: Male on left, female on right:)

adidas Harden Vol 4 Gila monster shoes

Earlier this year adidas in collaboration with famed basketball player James Harden released Vol. 4 of his namesake shoe. Why is sneaker news on a Gila monster website? Because a variant of the shoes are Gila monster pattern! And they are quite a match with our beloved venomous lizard’s intricate pattern. Previously, a Vol. 1 shoe was also called Gila monster pattern but they were similar colors and not patterned the same so not of real interest to me. But when these cam out, I knew a pair had to be mine! I haven’t played basketball in decades, but maybe I can wear them the Gila room to blend in a bit better:) Get yours here from adidas while you can, they seem to sell out fast!

2020 Gila monster breeding season begins!

With the babies I’ve held back are growing like weeds and coloring up beautifully, I’ve taken the adults out of brumation and am warming them up and will be feeding them their first meal soon. I’m both excited and nervous as to how this season will turn out. Will all the eggs paid be fertile? Will all the fertile eggs go to term? An educated guess says no to both but if improvements are made I am moving in the right direction.

I’ll be doing some new things this year. First, I’ll be pairing straight reticulated with reticulated, and banded with banded. Also, instead of leaving switching males between cages I will keep one male with one female for the duration of the breeding season. The females do seem to have preferences, and hopefully they still lie each other this year. I am waiting until the last week of March to start pairing as last year the females were not receptive and often attacked and bit the unrelenting males so it would be nice to avoid this drama and potential injury. I’ll keep everyone posted on the progress and of any successes and failures on my second year of breeding these amazing Gila monsters!

Day 153: It happens! Gila monster hatching success!


So, almost after all hope was lost on Day 153 the first Gila monster egg pipped from its leathery shell! Egg 02 at first cut a small slit and then a few more and over the next two days began to emerge from the egg. At first the baby Gila stuck its nose out, then it’s head, then half its body, and finally the entire body. It appears that hatching is a labor-intensive process as there are long pauses between progressive stages and also seems to be a good way of ensuring all the contents of the egg are consumed before leaving the egg. Over the ensuing days this process was (and currently is for two more lizards) repeated over and over, with Gilas emerging from their shell about two or so full days from pip to full emergence. Once the contents are completely devoured the neonate Gila monster leaves its shell and begins to wander the egg box. I witnessed one Gila that was out actually eating the egg yolk of another just coming out of its shell! Greedy bastard.

Once fully emerged and climbing around, the little monsters are pulled from the egg box, photographed, weighed, and set up solo in an 18 quart Sterelite box with paper towels as bedding and small water dish. The paper towel bedding serves as a clean substrate while the umbilical wound heals and the first few meals are eaten and passed through to make sure everything is going well. I will attempt the first feeding next week after the yolk has been fully digested and look forward to raising the babies from there!

I will be posting updates on the neonates growth, as well as some thoughts and insights on my first season captive breeding Gila monsters. Some reviews of the equipment I used is also likely in order as these items played an important role in my success. Whew, what an amazing season! The process has been fun, though frustrating and worrisome at times, and I look forward to greater success next year with these amazing reptiles!

Day 152: A watched egg never hatches

A Gila monster near hatch datePatience. Patience is what those in the know say. Sure, I am checking the incubator at least ten times a day for any action and patience is not my virtue, but I am old enough to know when to listen. A couple a the eggs dented in over two weeks ago, the two others are starting to dimple (not dent) and in all honesty I would be surprised if any of them hatch at this point. If they do not hatch my biggest concern is figuring out where my failure was. Is it the incubator? No, the Grumbach’s are renowned for their reliability. Is it the S.I.M. egg container? No, these have been used successfully with Gila monsters before. My temperature, though low, should not be the issue and my humidity is spot on, so it shouldn’t be that. We just started having cold fronts move through and temps have fallen so that may have a slight play into it (I have ordered a space heater to remedy this issue). At this point my guess is that since the fan in the Grumbach is unplugged that there may not be enough airflow which may be an issue, or the fact that the Pangea Hatch medium has started to grow mold adds to this theory. I do open the incubator to allow fresh air to enter but it may not be enough. Whatever the case, I will hold on hope until the last egg turns yellow and starts to sweat. If they all die I will carefully review my protocols and notes and seek the advise of successful breeders to plan for a better year next season!

On another note, I have stopped feeding my adults and am turning off the lights and under-cage heating in preparation of hibernation, which will begin after Thanksgiving. I have an old refrigerator that is hooked up to a Ranco thermostat for the cool down. Would be great if I could cool them in their cages but we do not see steady enough low temps here in northern Florida to ensure the Gila will reach and stay at 53°F for the three months of brumation.

Harmony Kingdom goes Gila monster in Tip the Scales

I started collecting Harmony Kingdom boxes in the mid-90’s after discovering them at a collectibles shop in the mall. They were mostly animal and my first box was, of course, a reptile (chameleons). For those that don’t know, Harmony Kingdom is a collectible series of themed boxes and figurines crafted by artisans in the United Kingdom. What caught my eye was the attention to detail and thoughtfulness put into the designs, with a nice dose of cheeky British humor. Though my collecting has slowed down over the years, I was very into it for some time and in an almost obligatory move mailed the company requesting a Gila monster box. Not saying that my letter reached the highest echelons of Harmony Kingdom or that it was even read, but in late 2009 the company released two versions of our favorite venomous lizard (you’re welcome).

Tip the Scales was carved by Master Carver Peter Calvesbert, hand-painted by local artisans in the Cotswold region of England, and comes in two versions. V1 is a normal colored Gila monster limited to 300 pieces, while Tip the Scales V2 is more of a bone-colored Gila and limited to 100 pieces worldwide! Very low numbers for the typical run for Treasure Jests and quite collectible.

These boxes are a must-have for any Gila monster enthusiast. The detail on these boxes is amazing, especially considering their diminutive size. The osteoderms look real as do the proportions of the body and look of the lizard. Besides the great detail and the beauty of these boxes, there are a some cool Easter eggs for us enthusiasts. Here is what the card that comes with the boxes say: “The Gila monster is a venomous lizard native to the southwestern U.S. and northern Mexico. Not only did Peter painstakingly sculpt its reticulated pattern, but he included numerous secrets. Its Latin name, Heloderma suspectum, means studded skin. Suspectum derives from palaeontologist Edward Drinker Cope’s suspicion that the lizard may be poisonous due to its teeth grooves. Gila refers to the Gila River Basin in Arizona, where these lizards were once plentiful. Exenatide is a drug used in the treatment of diabetes and is a synthetic version of a hormone found in the saliva of the Gila monster. Open the lid of this fixed edition box figurine to find a baby hatching Gila and Peter’s initials under one of the rocks.” The tent cards (cards that come inside the boxes and to be set up for retail display) can be downloaded from the Harmony Kingdom website here: V1  V2

The boxes pop up on eBay from time to time, and I have even seen one languishing in a store that needed rescue! So, have some fun and look for one or both of these amazing Harmony Kingdom Gila monster boxes, you will not be disappointed!!

New Gila Monster book from Dr. Hans-Joachim Schwandt

Fans of the fantastic website already know how knowledgeable and passionate Dr. Schwandt is about Gila monsters, and in September 2019 he released his long-awaited book on our favorite subject. Being the Gila geek I am, my order was placed the day pre-orders were announced and was certainly not disappointed when it arrived. The book covers a wide range of topics in detail and covers some information not previously seen in other books. Certainly a must-have for your collection of Heloderma reading, the book can be purchased from the author on his website or here.