The face of a Chihuahuan Hook-nosed Snake. These are small eaters of invertebrates. The subtle scoop on the end of the nose is helpful for finding prey in the sandy, grassland soil where they live.
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
Coachwhips are out and about on even the hottest days, rarely active at night. But they can still be found where they sleep, which is often up in trees high off the ground. We spotted this one doing just that just above eye level on a late night hike. These long, slender snakes are great climbers, and this is a reasonably safe spot for such an animal to evade predators and get off the hot ground.
A Gila Monster I followed to a nest of cottontails. It took a while, but it ate all three of them that were in there. Amazingly, they all fit, and the lizard ambled off to rest under an overhanging root in the drainage. It was a good example of how the venom of Gila Monsters is not necessary for predation, as the venom played no apparent role in the capture or consumption of its prey.
A rattlesnake that looks like a rock. This Southwestern Speckled Rattlesnake was found in central Arizona in an area of rusty granite and quartz. The resulting cryptic pattern is just as colorful, including speckled grey blue eyes. Though it is brightly colored, these snakes can be very difficult to see in context.
Crowell, H. L., Whelan, J. M., & Harmel, M. V. (2020). Rattlesnake colouration affects detection by predators. Journal of Zoology, 310(1), 1–11. https://doi.org/10.1111/jzo.12786
Hanscom, R. J. (2025). From ambush to activity: Using accelerometry to reveal cryptic behaviors of rattlesnakes and kangaroo rats [Doctoral dissertation, University of California, Riverside]. eScholarship. https://escholarship.org/content/qt4ft2985w/qt4ft2985w.pdf
A Twin Spotted Rattlesnake at her high elevation retreat. Accessing these areas is somewhere between difficult and impossible, but they’re perfect for a small montane rattlesnake.
A small Banded Rock Rattlesnake in ambush along the base of a boulder in southeastern Arizona. The pattern and bands break up its shape, making it difficult to see in context. This is a good way to catch one of the many Yarrows Spiny Lizards jumping around on the same rocks each morning.
A Southwestern Speckled Rattlesnake in ambush on a humid night a couple of years back. Like many other desert reptiles, the monsoon and period after are the most active times of year. Humid air and cooler, stable temperatures make for safer activity, and a lot has to be done in a relatively short amount of time.
A Twin-Spotted Rattlesnake with a relatively drab pattern, but not atypical for an older adult. These are small snakes, rarely seen by hikers, as their range within the U.S. consists of only a handful of mountains in southeastern Arizona. In addition to rodents, these rattlesnakes also specialize in lizards, often taking the colorful Yarrows Spiny Lizards also common to rocky outcrops in high pine forests. These are among the protected species within Arizona, but a good number of them still end up being taken from the mountains each year to enter the European black market.
Prival, D. B., Goode, M. J., Swann, D. E., & Schwalbe, C. R. (2002). Natural history of a northern population of twin-spotted rattlesnakes, Crotalus pricei. Journal of Herpetology, 36(4), 598–607. https://doi.org/10.1670/0022-1511(2002)036[0598:NHOANP]2.0.CO;2
Prival, D. B., & Schroff, M. J. (2012). A 13-year study of a northern population of twin-spotted rattlesnakes (Crotalus pricei): Growth, reproduction, survival, and conservation. Herpetological Monographs, 26(1), 1–18. https://doi.org/10.1655/HERPMONOGRAPHS-D-11-00002.1
Prival, D. B., Goode, M. J., Swann, D. E., & Schwalbe, C. R. (1999). A comparative study of hunted vs. unhunted populations of the twin-spotted rattlesnake. Unpublished report, University of Arizona. PDF link
Grabowsky, E. R., & Mackessy, S. P. (2019). Predator-prey interactions and venom composition in a high elevation lizard specialist, Crotalus pricei (Twin-spotted Rattlesnake). Toxicon, 170, 88–97. https://doi.org/10.1016/j.toxicon.2019.09.003
Grabowsky, E. (2018). Venom composition of little known mountain rattlesnakes and predator-prey interactions of Crotalus pricei pricei and its natural prey, Sceloporus jarrovii (Master’s thesis). University of Northern Colorado. https://digscholarship.unco.edu/theses/251/
Bezy, R. L. (2021). Biogeographic outliers in the Arizona herpetofauna. Sonoran Herpetologist, 34(2), 45–58. PDF
Pough, F. H. (1966). Ecological relationships of rattlesnakes in southeastern Arizona with notes on other species. Copeia, 1966(4), 649–658. https://doi.org/10.2307/1441401
Bezy, R. L., & Cole, C. J. (2014). Amphibians and reptiles of the Madrean Archipelago of Arizona and New Mexico. American Museum Novitates, 2014(3810), 1–24. https://doi.org/10.1206/3810.1
Kauffeld, C. F. (1943). Field notes on some Arizona reptiles and amphibians. The American Midland Naturalist, 29(2), 342–359. https://doi.org/10.2307/2420795
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