The Forecast: Cloudy with a Chance of Lizards!


Female Phrynosoma asio.

We left Seattle for México with one plan in mind: to find three species of elusive horned lizards (genus Phrynosoma). Plans changed. We adapted. The trip evolved. Immediately after leaving the airport, a change in plans. We wanted to make a bee-line to our hotel to avoid México City traffic, some of the worst for any major city in the world. The moment we left the rental car parking lot with our wheels for the week, a seven-seater minivan, the GPS unit malfunctioned: “Lost satellite reception…recalculating”, became its mantra. This was going to be an interesting trip… Forty kilometers and three hours later, along potholed alleys and horrific traffic on the second longest avenue in the world (Avenida de los Insurgentes), we were at our México City hotel. In the morning, we would meet up with professors and students from the Universidad Nacional Autónoma de México (UNAM) and go to the field to catch some lizards.

Horned lizards belong to the genus Phrynosoma, one of nine genera within the diverse lizard family Phrynosomatidae. Sixteen species of Phrynosoma are currently described and can be found from the Isthmus of Tehuantepec in the south to southern Canada in the north. Though the general bodyplan is fairly conserved, a comparison of horn morphology, tail length, and scalation patterns reveals a high level of morphological diversity within this genus. These lizards are notorious for their incredibly odd anti-predation behavior of squirting blood from their eyes moments before the would-be predator is about to chomp down on our favorite scaled pancake. However, not all species perform this behavior, and this response is generally limited to canid predators. My advisor, Dr. Adam Leaché, is interested in reconstructing the evolutionary history of this group to further understand the biology of these enigmatic little beasts.

To do so, we have to obtain DNA from all 16 species. Fortunately for us, we are able to procure DNA for many of the species through natural history museum collections, a resource that has helped countless numbers of scientists for decades. Fortunately for us, some species are not represented in museum collections, which means…fieldwork! For this trip, we had three target species, all endemic to southern México: P. braconnieri (short-tail horned lizard), P. taurus (bull horned lizard), and P. asio (giant horned lizard). These three species do not have genetic resources in museum collections for a simple reason: they are not easy to find. To increase our chances of success, Adam put in a lot of legwork before our trip, planning exact localities to visit and coordinating with United States and Mexican researchers alike who have worked on these lizards for many years.

           When we left México City for the field, we were five: Dr. Adam Leaché, Dr. Wade Sherbrooke, Dr. Adrián Nieto Montes de Oca, Rafael Lara, and myself. Wade was the director of the Southwestern Research Station of Arizona’s Chiricahua Mountains (operated by the American Museum of Natural History) for over 20 years and has been passionate about studying and understanding the natural history of horned lizards since the 1960s. Wade also wrote the quintessential field guide to Phrynosoma, “Introduction to Horned Lizards of North America”. Adrián is a professor at UNAM who has worked throughout México on a variety of reptile and amphibian projects since the 1980s. And Rafael (Rafa) is a master’s student at UNAM studying the thermal physiology of many Phrynosoma species. Needless to say, we had a top-notch field team with all the prerequisites for a successful trip. And oh yes, of course we’d stop for other lizards along the way! We are, afterall, herpetologists.
Team Phrynosoma consisted of students from Mexican universities in Guerrero and Mexico City (UNAM), professor Adrian Nieto Montes de Oca (UNAM), professor Adam Leaché, Wade Sherbrooke, and myself.


           Our first destination was Tepanco de Lopez, a small town in southeastern Puebla, where Wade had found five P. braconnieri eight years prior. We tested our luck in town with some locals, “Usted tiene tacos de cameleón?”. “No”, she said, no Phryno-tacos here, with an awkward chuckle. We made our way to the site via Wade’s memory, passing cinderblock buildings, stray dogs, anthills, and active farms. We reached the site by 4pm, and we all bounded from the car with cheerful optimism, walking excitedly on our toes, alert for any subtle movements on the ground. The habitat was characterized by white soil and rocks beneath a variety of cactus, Agave, and Acacia species, with the flora changing abruptly with the direction of the slope. After 2-3 hours roaming the hill, we returned to the car, disappointed and frustrated; no Phrynosoma today. We did, however, catch a little Tantilla (black-headed snake) and Sceloporus jalapae (Jalapa spiny lizard). Back at the hotel, we commenced our nightly routine of specimen preparation, note keeping, and relaxation.

           Later that night I woke up to a regular Seattle sound: rain. “I hope this won’t hamper tomorrow’s herping”, I thought. After breakfast accompanied with fresh squeezed orange juice, we headed back to the same site under a grey sky. The sun never broke for more than three minutes, and the wind was moderate; the lizards were hunkered down. After roughly three hours on the hill, we collected three S. jalapae and a Salvadora (patchnose snake) that Adam spotted on the ground. Still no Phrynosoma. It was time to try our luck elsewhere.

           Our destination was El Jardín Botánico, a nature preserve known for its high cactus diversity, located about 18 miles due north of our previous site. Rafael had good word that P. taurus and P. braconnieri are “easy” to find here. Just the morale booster we needed! Within 50’ of the car, parked at the visitor center, we found our first P. taurus! Well, they were in tanks in the visitor center, three females and two males. Seeing them in this context did not make the site any less spectacular. Their swept back temporal horns as seen from above reminded me of the Star Trek symbol. Unfortunately, there was a misunderstanding and we were not allowed to collect in the preserve, which made sense and we of course abided. However, the habitat looked so spectacular that we couldn’t pass up the opportunity, so we tried our luck outside the Jardín at a nearby locality.

           The hillside we scoured was full of a great diversity of plants, including great thick Yucca (approaching 4’ at the base) and a variety of other plants full of spines, thorns, and prickles; “Every plant is out to kill you”, Adam said. Goats traveled this hill frequently, and we followed their trails to avoid the incessant scrapes and cuts from the thorny outstretched branches. In addition to two Sceloporus gadoviae (Gadow’s spiny lizard) that we caught here, Adrián collected some Agave spines in his palm when diving after what he believed to be a Phrynosoma. After tallying up another 0 point day for the herpetologists, we stopped at a local restaurant for some deep-fried caterpillars (cuchamá), micheladas (a beer added to lime juice and chili powder), and a Mexican Burt Reynolds look-alike singing on TV.

           Day 3: we discover that we are in the midst of hurricane Carlotta. “Oh yeah, that would explain all the great weather we’ve been having!”, I thought. A decision had to be made: sit in the hotel room here in Tehuacán and wait out the weather (“The sky looks lighter grey now, or is it just me?”), or drive south to Guerrero and hopefully experience more friendly weather. We knew we had P. asio and P. taurus waiting for us in Chilpancingo, Guerrero, because a student was using them for thermal tolerance studies in the lab. Furthermore, Wade wisely pointed out that you never find anything when you sit still. The decision was made: to Chilpancingo!

           The 4.5 hour drive on the cuota was pretty in a lot of spots, but rainy in most. Shortly after sunset, a small plague of large white moths descended upon the highway, perhaps drawn to the headlights. Once in Chilpancingo, the car needed fuel, and so did our bodies. We stopped at the first taco stand we saw and tried our luck with some tacos de cabeza, not to be confused with tacos de sesos…brains. Dos sopes, quatro tacos, y una jamaica later, we were fueled up and ready to stretch our legs and do some late night herpin’!
Work was fueled by great street food such as these tacos de cabeza (head, not brains!).


           With the wet weather, we were certain to find some amphibians, while also being hopeful to find Anolis (anoles) for a long-term project Adrián has been working on. Driving through the dripping rain, we saw well over 50 Spea multiplicata (Mexican spadefoot frogs) on the road. At our first roadside stop, we could hear the mellifluous sounds of Spea and Syrrhophus pipilans (eleutherodactylid frog) choruses in the distance. We hiked a little trail into the forest, where we spotted the eyeshine of many moths, and watched male S. pipilans singing from the top of epiphytes, but no Anolis, so down the road we went.

           Though we have the eyes of herpetologists, our search image is often triggered by arthropods, especially large arthropods. Adam found a big vinegaroon (order Thelyphonida) on a roadcut, an arachnid named for its ability to spray an acetic acid substance in defense. Even with a mission at hand, the naturalist has to stop and appreciate such beauty. Back to the Anolis. Anolis are most easily seen at night by spotting with a headlamp, as their light-colored bodies reflect the light and stick out against the dark foliage. Dead leaves, moths, and broken sticks can all be mis-identified as Anolis with a little bit of over-excitement. With no signs of Anolis after nearly two hours of searching, it was time to head back to the hotel. But on the walk back to the van, the highlight of my night was crawling on the roadcut, Coleonyx elegans (Yucatán banded gecko)! I was not anticipating finding a gecko here, so this was a great way to end the night.

           Today’s weather report showed a change in weather, the clouds were breaking. We were hopeful, we felt a bit of luck in the air. Marcos, Diego, and Antonio, three students studying Phrynosoma at the UNAM in Chilpancingo, came to our hotel the following morning at 8:00am to take us to a known locality of P. asio and P. taurus: inside Marcos’ house. In his apartment, he had 11 P. asio and 7 P. taurus that he had collected, performed tests on, and now needed to go back to the field. The first impression one gets of these animals is pure delight. They are so fascinating. You feel like you are looking back in time when examining their horns, scales, and eyes. While photographing these lizards outside of our hotel in the scattered sunlight, some local children told us they had just seen one up the hill. “Sí, sí, un cameleón!” If there is one thing I’ve learned from this trip, it is to befriend the locals, and listen to them. They will tell you where to go, what to do, and how to find what you are looking for. They might even give you a beer, too.

Jared Grummer with a male and female Phrynosoma asio, the giant horned lizard. They subsequently mated after they were released.

           Up the hill we went, past pigs, turkeys, and cattle. There were a few cactuses and woody plants, but most of the hillside was grazed and beaten down from livestock. Within a couple minutes, “Tengo uno!” – Marcos had found a P. asio adult at the base of a cactus! Two minutes later, Antonio found three juveniles right next to each other. Three minutes after that, I found a nice male. While posing for a photo with a male in one hand and a female in the other, the male started bobbing his head, a sort of “How you doin’?” in the female’s direction. We placed both on the ground, and the male ran over immediately to the female and mounted her. We watched the rarely witnessed act of P. asio copulation for the next 15 minutes. Following some impromptu P. asio post-copulatory behavioral observations that Wade was curious about, we headed across the road to try our luck with finding P. taurus.
The sky turned back to grey in the mid-afternoon, but the locals we were with remained hopeful. We searched the gravely road under the telephone wires in the shrouded daylight. “Diego!” Antonio had found an impossibly cryptic juvenile P. taurus on the gravel near the road, and Diego was summoned to take the air temperature, substrate temperature, and cloaca temperature, of every Phrynosoma that was encountered. Amidst the grey weather (air temp ~74F), we found about six more P. taurus in this short, deciduous forest. The disruptive dorsal patterning of this species works incredibly well at camouflaging these lizards to the forest floor of dead leaves and dark soil. And they don’t move, not even if you step near them, or on them. Did I mention that there aren’t many in museum collections? Yes, they are hard to find. But, the sun had come out for a little while. The lizards were out. Two out of three target species were caught. Guerrero was good.

Phrynosoma asio pair during courtship.
           The next morning, we drove to a locality about 50 minutes outside of Chilpancingo to find another population of P. taurus. This site was a little higher in elevation, with oaks amidst farmland. The habitat was a grassy south-facing hillside with exposed orange soil and rocks from erosion. “Diego!” We had found our first P. taurus of the day. “Diegoooooooo!!” Eight more were found within the hour. The coloration of this species is highly variable and matches the predominant soil color very well at each locality. This population, sadly, is in jeopardy. With farms in all directions, it is conceivably only a matter of time until this habitat is converted into agricultural land. Many other populations in the area face the same tenuous future.

            Despite the weather, we were having a successful trip. One out of three target species remained: P. braconnieri. This species is arguably the most elusive and secretive Phrynosoma, along with the poorly-studied P. ditmarsi in northern Sonora. But we had learned how to find these lizards: talk with the locals. A student from UNAM in México City was studying the thermal biology of P. braconnieri, and he had some specimens back at his house. Alfonso has been successful at finding and capturing P. braconnieri in the field, he figured he’d found over 100 during a couple months of fieldwork. He showed us videos at his house that he had taken demonstrating the ability of P. braconnieri to move water from their dorsum to their mouth through some sort of capillary action or active transport. Though researchers know of this phenomenon, it is not well studied. Picking up horned lizards from peoples’ houses is not how we envisioned our “field” collecting would go, but with such a short trip and real world collecting difficulties, we were happy to check off our third target species.

             One final obstacle, potentially the biggest, lay in front of us: specimen export. Exporting specimens from any country is no small feat, but thankfully we had Adrián, who was determined to get these specimens out with Adam. After Adrián filled out paperwork for over two hours, we headed to the airport to get the green light from PROFEPA (Procuraduría Federal de Protección al Ambiente), the government agency that controls all environmental/natural exports. The PROFEPA agent plugged away at the computer for nearly an hour, but it seemed that Adrián had filled out something incorrectly. There was no way around it, we had to re-fill out the paperwork. The agent was very nice to us, so he was rewarded with a Krispy Kreme sprinkled donut and Starbucks coffee, which he happily and quickly dispatched. We did not receive the okay we were looking for, we were frustrated; it was time to watch a UEFA cup fútbol game.
Female Phrynosoma asio in her suburban habitat

             We returned to Adrián’s house following the game (Portugal 1, Czech Republic 0) to re-prepare the specimen paperwork. On the second round, Adrián whizzed through the paperwork (the application is timed, one hour) while Adam and I wrapped and packed the specimens for the (hopeful) journey to their new home at the University of Washington’s Burke Museum of Natural History and Culture. In the morning, the agent asked to see the new paperwork and a look at the specimens. “Bien, bien.” All was good, Adam had the green light! Sorry, but no more donuts today. At 6:35, Adrián and I left the airport. Everything was in place, Adam was on his way to Seattle with three species of horned lizards.

Our journey started and ended with five people, went through five states, over five days, and 2,200km on the road. We had met many colleagues and made many friends along the way. Plans were made, and plans were changed. Though the weather was far less than ideal, expertise, wisdom, and local knowledge paved the way for a successful trip. We had looked, and failed. We had searched, and succeeded. We were, cameleoneros.

Text and captions by Jared Grummer.

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