GILA MONSTERS LIVEN UP THE DESERT WORLD
By Whit Gibbons
Thirty years ago, I took my teenage son, Mike, on a field trip to Arizona. He wanted to see some rattlesnakes and a Gila monster in the wild. On that trip we found nine different rattlesnake species but never saw a Gila monster, America’s largest lizard and its only venomous one. Last August we took Mike’s teenage son, Parker, to Tucson to give it another try.
The Sonoran Desert is a fabulous ecosystem, where giant saguaro cactuses taller than the mesquite trees dominate the landscape, and summer temperatures routinely reach 100 to 110 degrees Fahrenheit. Anyone who appreciates seeing an array of native plants and animals that have adapted to arid habitats will not be disappointed. In the Southeast, August is the month to escape from summer heat. In Arizona, August is monsoon season, prime time for seeing wildlife, especially reptiles. Torrential rains, unpredictable and sporadic, move through the region, bringing the desert to life.
Against this backdrop of desert terrain and weather, our primary goal was to find reptiles, amphibians and other wildlife – as many different kinds as possible. During the day, lizards scooted across the desert floor from the shade of one cactus to another. Whiptail lizards with their yellow racing stripes run faster than a desert wind. Catching one by hand is virtually impossible, but many stopped to pose long enough for a photo.
Most snakes make their appearance with the onset of cooler nighttime temperatures, starting at what herpetologists call the golden hour, sunset. Sure enough, we found several sidewinders, western diamondbacks and two other kinds of rattlesnakes. Hand-size tarantulas were fairly common. Looking like something straight out of a horror movie, they are easy to pick up. Put one hand on the ground and poke them in the rear with the other. I’ve never known one to bite a person. During and after a frog-choker rain is an ideal time to look for some desert animals, especially amphibians. One rainy night we saw Sonoran Desert toads, the largest one about the size of a dinner plate. Every night we walked up rocky canyons or dry washes, drove carts along an 18-hole golf course or rode along back roads knowing a wildlife adventure could be around the next bend.
As the week drew to a close we had encountered big jackrabbits, a California kingsnake, banded geckos and other animals in their native habitat. But no Gila monster. We began to think that quest was in vain. Then, on our final night in Arizona, as we walked along the last hundred feet of a 2-mile canyon trail, Mike gave a yell and pointed to a Gila monster within a few feet of the path. Parker and I had walked right past it. Gila monsters are fat lizards, with skin that looks like a covering of orange- or pink-and-black pebbles. The large rounded tail, half the length of the body, serves as a storage compartment for fat and water. The black tongue is forked like a snake's, and the lizard's food includes other lizards, rodents, birds and bird eggs. The head and body are covered with a primitive armor of bony plates beneath the skin, making it impenetrable by the teeth of most predators. Our Gila monster was about 18 inches long and a bit hissy about our interrupting its nighttime stroll with three flashlight beams. We watched in awe for several minutes. Mission accomplished.
Why take such a field trip? I can think of many reasons: to see nature’s amazing diversity on its own stage; to watch a live performance rather than a video; to experience firsthand the heat and the rain. I’m ready for the three of us to go back during the monsoon season. This time we can add to Parker’s rattlesnake list without having to search for a Gila monster at the same time. One thing’s certain, I’m not going to wait another 30 years.
Dr. Whit Gibbons is Professor Emeritus of Ecology, University of Georgia, and former Head of the Environmental Outreach and Education program at the Savannah River Ecology Laboratory (SREL). He currently serves on ARC's Board of Directors.