(they don’t want to bite you)
On May 16th, 2021, I hopped on a flight from Newark to Tucson. A few hours later, in an unfamiliar airport in Arizona, I met a professor I’d never spoken to in person, linked up with a fellow volunteer I’d only communicated with via text, and was handed the car keys of the PhD student for whom I would spend the summer working. The PhD student in question was 160 miles away, at our final destination, a place cartographers might lovingly call the middle of nowhere.
That was the beginning of the wildest — and most snake-filled — summer of my life.
The small town of Rodeo, New Mexico is not actually even a town. It’s so miniscule that it’s merely a “census-designated place.” But if you like reptiles and amphibians, you might’ve heard of it anyway; the spot is a mecca for herpetologists. The surrounding landscapes are chock full of enough snakes, lizards, frogs, and toads to draw herp-lovers from all around the country and world.
The region also proved to be the perfect field site for Dylan Maag, the PhD student who had hired me. Dylan was in the thick of his doctoral research in Rulon Clark’s lab at San Diego State University, and had recruited me and four other volunteers to spend a summer helping him gather data for his project studying hybridization between two rattlesnake species.
Prairie (Crotalus viridis) and Mohave Rattlesnakes (Crotalus scutulatus) are both found in lowland regions of southwestern New Mexico. They overlap in a narrow area wherein the two species hybridize — that is, mate with each other and produce hybrid offspring. According to evolutionary theory, when hybrids survive and mate less effectively than their parent species, breeding between the two species will be selected against and reproductive barriers (behavioral or biochemical) will develop; this is the mechanism thought to maintain a species’ distinctiveness. Alternatively, should hybrids have some fitness advantage, adults would seek to breed with the other species, and soon the two parent species would be indistinguishable. Dylan’s research sought to compare a number of ecological and morphological characteristics of Prairies, Mohaves and their hybrids, including hunting behavior, habitat choices, physical characteristics, and venom composition. With these data, he could unveil the mysteries of this particular hybrid zone.
One of the pillars of the project was information on movement patterns — figuring out exactly where the snakes were, and what they were doing, at certain points of the day. That summer, we were tracking snakes that were toting radio transmitters. Using an antenna and receiver tuned to the transmitter’s signal, you could zero in on the snake’s location any time you wanted, walk over there, and see exactly where they were and what they were doing. Easy!
At least, that’s the idea.
That’s how I found myself traipsing through the desert in the middle of the night, scanning the landscape with my headlamp, veering this way and that as the beeping of my receiver got louder or quieter, all my efforts bent on finding an animal that most would have done anything to avoid. To this day, it’s probably the coolest thing I’ve ever done.
On one particular night, a Mohave Rattlesnake named Mo was giving me trouble. The beeping of my receiver told me he was close, but I couldn’t spot him. The desert was littered with mesquite bushes and tufts of grass — plenty of places for a snake to hide — and you couldn’t just go crashing through the brush until you found your target. For one, Mohaves are venomous. There’s nothing to fear if you keep a respectful distance, and the snake gaiters we all wore helped protect our lower legs, but caution was still warranted. And two, the integrity of Dylan’s data depended on each snake’s behavior remaining natural. Scaring them into the open would compromise the observation.
Scan around with my receiver. I think he’s in this direction…
Some careful movement, scrutinizing the ground where I’m walking. Scan again. Maybe not…
The radio receivers could get you most of the way there, but they weren’t exactly instruments of superb precision. If you were close to the animal, as I was, the signals could get confusing.
Scan, scan, scan. Where IS he?
And then I looked down and finally — finally — saw Mo… curled up next to my boot, as if he had materialized out of thin air.
I’d narrowly missed stepping on one of the most feared rattlesnakes in the world.
I’d like to make a brief aside here to give props to snake camouflage. Yes, it was dark, and yes, there were abundant hiding spots. But I was actively searching with practiced eyes, I was shining a bright light around, and for goodness’ sake, Mo was literally beeping at me.
And I still didn’t see him until I was right on top of him.
I’d like to think I’m a pretty nice person, but Mo had no way of knowing that I wasn’t out to get him. To Mo, I was a potential predator (no rattlesnake will ever look at a human and think prey item — we’re just far too big). I was a freaky giant who had just set their freaky giant boot right in his personal space. If a giant had done that to me, and I had been toting fangs and venom, I probably would have felt justified in using them.
But Mo never struck at me. If my memory serves me correctly, he didn’t even slither away!
My point is this: even when confronted with a real threat, Mohaves are disinclined to engage with humans. I’d accidentally strayed very close, close enough that Mo would have been justified in thinking I was trying to eat him, and thus attempting to inflict a defensive bite. But Mo just wanted to be left alone, and decided that staying hidden was his best chance at doing that.
Dylan and Rulon have already begun to analyze data from this and other studies. In over 8,000 hours of video footage of snakes coiled up, hunting for prey, never once did they observe a snake attacked or killed by predators. Snakes are likely hesitant to leave their coils because they’re much safer in that position. Striking at me could have protected Mo, but it also would have shattered his near-perfect camouflage. Mohaves are infamous for their ability to hurt people, but attempting to do so is often their last resort.
In general, snakes — not just Mohaves — want absolutely nothing to do with you and me. I was familiar with that fact, and certainly wasn’t wandering the desert under the illusion that rattlesnakes were out to get me. But the memory sticks all the same — seeing the principle up close and personal is quite different than reading about it on the Internet!
I wouldn’t recommend getting close enough to a rattlesnake for him or her to bite you, but if you ever find yourself there by accident, take heart: if they’re anything like Mo, you should be just fine.
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