A Mojave Rattlesnake on the crawl after a wet night in southeastern Arizona. It’s moving laterally, hissing and watching the perceived predator with the camera, but not rattling. As this species often does, instead, it curls its tail and “wags” it slowly as a display. Prairie Rattlesnakes, notably, will often do this tail-curling behavior instead of rattling.
This guided retreat, where the snake moves laterally to cover while keeping the business end pointed forward, causes a lot of confusion with observers. For one, it’s not always a straight line away, but to cover. That cover can be a vehicle, bushes, or a cast shadow … including from the person watching it. This, and confirmation bias from decades of beloved folklore, contribute to the many tall tales about Mojave Rattlesnakes.
Greene, H. W., & May, P. G. (2002). Parental behavior by vipers. In G. W. Schuett, M. Höggren, M. E. Douglas, & H. W. Greene (Eds.), Biology of the Vipers (pp. 179–205). Eagle Mountain Publishing.
Cardwell, M. D. (2013). Behavioral changes by Mohave rattlesnakes (Crotalus scutulatus) in response to drought. California State University, Sacramento.
Maag, D. W., Francioli, Y. Z., Goetz, M. T. H., & Sanders, L. N. (2025). Variation in defensive and exploratory behaviors across a rattlesnake (Crotalus scutulatus × viridis) hybrid zone in Southwestern New Mexico. Scientific Reports, 15(1), 2345. https://doi.org/10.1038/s41598-025-96155-8
Calvete, J. J., Massey, D. J., Sánchez, E. E., Sanz, L., & Bush, S. P. (2012). Venom variability and envenoming severity outcomes of the Crotalus scutulatus scutulatus (Mojave rattlesnake) from Southern Arizona. Toxicon, 60(9), 802–810. https://doi.org/10.1016/j.toxicon.2012.06.004
A Mojave Rattlesnake near Phoenix, Arizona last year. This relatively young snake. While the old idea of counting rattle segments to tell the age of a snake isn’t accurate, much can still be learned. For instance, this snake still has its prebutton intact, which it was born with – its first shed skin revealing the full button. Then two articulated segments, and a the basal segment mean this snake has shed three times in its life. Given the strong and steady taper of segments and very healthy weight, and time of year it was found (late in the monsoon): this snake had just had its first birthday. As usual, it’s not green … and not “aggressive”. These timid snakes, like any other rattlesnake … or any other animal … will do all they can to prevent their own death. Add in a lifetime of hearing from everyone around that they are aggressive and chase you down on sight, not a small amount of social media distortion, and a sprinkle of personal identity reliance on contrived threats, and you have the most feared animal in the West.
But if this is you … it’s not your fault. Your brain can lie to you. In fact, with things you may fear, it can do so quite effectively. So while many stories of Mojaves chasing someone through the desert are flat-out lies, many are not. The reason: just like the snake, you are programmed for survival. In some cases, this means adding a few exclamation points to perception and memory.
And if you don’t buy that your brain can lie to you: open a new tab and look up any optical illusion. Right there in front of you: your brain is lying. Then, read these publications:
1. Riskind, J. H., Moore, R., & Bowley, L. (1995).
The looming of spiders: The fearful perceptual distortion of movement and menace. Behaviour Research and Therapy, 33(2), 171–178. https://www.sciencedirect.com/science/article/pii/0005796794E0023C
This paper explores how fear increases the perceived motion and menace of feared objects such as spiders and snakes. Fearful individuals overestimated the movement of spiders/snakes, evidencing distorted space/time perception under phobic conditions.
2. Öhman, A., & Mineka, S. (2003).
The malicious serpent: Snakes as a prototypical stimulus for an evolved module of fear. Current Directions in Psychological Science, 12(1), 5–9. https://journals.sagepub.com/doi/abs/10.1111/1467-8721.01211
This article theorizes that fear of snakes activates an “evolved fear module” in the brain, causing rapid and automatic responses to snake stimuli. It suggests deep-rooted neurocognitive pathways shape the perception of danger.
3. Teachman, B. A., Gregg, A. P., & Woody, S. R. (2001).
Implicit associations for fear-relevant stimuli among individuals with snake and spider fears. Journal of Abnormal Psychology, 110(2), 226–235. https://www.academia.edu/download/49240316
Using implicit association tests, this paper reveals distorted cognitive processing of snake stimuli in phobic individuals. It supports the idea that fear biases long-term memory and perception of threat magnitude.
4. Soares, S. C. (2010).
Fear commands attention: Snakes as the archetypal fear stimulus? [Doctoral dissertation]. Karolinska Institutet. https://openarchive.ki.se/articles/thesis/Fear_commands_attention_snakes_as_the_archetypal_fear_stimulus_/26901778/1/files/48943789.pdf
This dissertation offers detailed experiments demonstrating that snakes command disproportionate attentional resources, even in peripheral vision, leading to spatial distortion and overestimated danger.
The most dreaded snake in the West? Likely. For good reason? Not really.
This one is typical for Maricopa County, Arizona. Some may have a green hue, but most are a muted brown or tan. They tend to have a more “clean” look than the more familiar Western Diamondback Rattlesnake, showing less speckling and a tendency to have each scale be its own color.
Mojave Rattlesnakes are common in areas of relatively flat sandy desert scrub and grasslands. Despite their behavior not being meaningfully different than other rattlesnake species, they are often attributed with fanciful abilities and aggressive traits. When someone tells a tall tale that they were chased on horseback for miles or a snake popped a truck tire, it’s usually about these … whether or not this species actually even lives in the area the story occurred is another story.
Their venom, too, is largely a matter of American folklore. It is highly toxic, often involving neurotoxins and a mix of other fun stuff. But it’s highly variable based on region and other factors. A bite from a Mojave Rattlesnake is of course serious business requiring immediate emergency care, but the rumors about not having antivenom or a sure death within minutes are made up.
1. Minton, S. A., & Weinstein, S. A. (1986). Geographic and ontogenic variation in venom of the western diamondback rattlesnake (Crotalus atrox). Toxicon, 24(1), 71–80. https://doi.org/10.1016/0041-0101(86)90167-4
2. Peterson, M. E. (2006). Snake bite: Pit vipers. Clinical Techniques in Small Animal Practice, 21(4), 174–182. https://doi.org/10.1053/j.ctsap.2006.09.004
3. Glenn, J. L., Straight, R. C., Wolfe, M. C., & Hardy, D. L. (1983). Geographical variation in Crotalus scutulatus scutulatus (Mojave rattlesnake) venom properties. Toxicon, 21(1), 119–128. https://doi.org/10.1016/0041-0101(83)90055-7
4. Hardy, D. L. (1983). Envenomation by the Mojave rattlesnake (Crotalus scutulatus scutulatus) in southern Arizona, USA. Toxicon, 21(1), 123–129. https://doi.org/10.1016/0041-0101(83)90054-5
5. Sánchez, E. E., Galán, J. A., Powell, R. L., Reyes, S. R., Soto, J. G., Russell, W. K., … & Pérez, J. C. (2005). Disintegrin, hemorrhagic, and proteolytic activities of Mohave rattlesnake (Crotalus scutulatus scutulatus) venoms lacking Mojave toxin. Comparative Biochemistry and Physiology Part C: Toxicology & Pharmacology, 140(2), 221–230. https://doi.org/10.1016/j.cca.2005.05.020
6. Holstege, C. P., Miller, M. B., Wermuth, M., Furbee, R., & Kirk, M. A. (1997). Crotalid snake envenomation. Critical Care Clinics, 13(4), 889–912. https://doi.org/10.1016/S0749-0704(05)70373-0
7. Cardwell, M. D., Massey, D. J., & Smelski, G. (2022). Mohave Rattlesnake (Crotalus scutulatus) Identification Revisited. Wilderness & Environmental Medicine, 33(2), 234–241. https://doi.org/10.1016/j.wem.2022.01.003
8. Strickland, J. (2018). Evolution and Distribution of Phenotypic Diversity in the Venom of Mojave Rattlesnakes (Crotalus scutulatus). [Doctoral dissertation, University of Central Florida]. https://stars.library.ucf.edu/etd/6054/
9. Rael, E. D., Lieb, C. S., & Maddux, N. (1993). Hemorrhagic and Mojave toxins in the venoms of the offspring of two Mojave rattlesnakes. Journal of Comparative Physiology B. PDF via Academia.edu
10. Aird, S. D., Thirkhill, L. J., Seebart, C. S., & Kaiser, I. I. (1989). Venoms and morphology of western diamondback/Mojave rattlesnake hybrids. Journal of Herpetology, 23(2), 85–90. https://www.jstor.org/stable/1564018
A young Mojave Rattlesnake at rest, lifted just off the surface of the warm sand to get a little air flow. Thermoregulation is far from just “sunning” – much of the activity of reptiles in the desert during the summer is about getting cooler, rather than warmer.
