Sidewinder Crotalus cerastes

Sidewinders have a famous name and are extremely common where they are found, yet are quite uncommon to see for most. They live in flat, sandy scrubland desert, and avoid rocky areas and hills. They're very small snakes, reaching an adult size of only around 2 feet. They can be most easily identified by their distinct sideways motion (sidewinding), where the snake throws a loop of its body forward and pulls the rest along rather quickly. They also have two very visible 'horns' above the eyes, which helps the sidewinder live in sandy environments. Although they are small, this snake can give a very bad bite and should never be bothered. Three subspecies are found in Arizona.

These snakes are under two feet long, with females being slightly larger as full-grown adults. There are several reasons this may be the case, one of which being that a bigger snake can produce more babies.

These rattlesnakes don't, and may not really be able to, slither like most snakes do. They can move in a straight line rectilinear motion, undulating belly muscles to inch forward. But more typically, they throw a loop of the body forward, past its head, and then bring the rest of the body alongside it. This is the side-winding method they're named for. It's a good way to move through a sandy, hot environment ... often with some speed.

The tracks left behind are a series of unconnected lines with a "J" at the end, pointing in the direction of travel. This is different than is often expected by homeowners, who report a "sidewinder tracks" that are typically from fast-moving nonvenomous snakes, like coachwhips and whipsnakes, moving quickly through soft matrix, leaving a swishing side to side track.

And yes, there are sidewinders elsewhere in the world ... but they're not closely related to these snakes, and are not rattlesnakes. They are a great example of convergent evolution, where a similar solution evolves to meet similar problems. In this case, it turns out that side-winding is a very efficient way to move for a snake, and sandy deserts on the other side of the world are no different.

Webber, M. M., Jezkova, T., Glaudas, X., & Rodríguez-Robles, J. A. (2016). Feeding ecology of sidewinder rattlesnakes, Crotalus cerastes (Viperidae). Herpetologica, 72(4), 324–330. https://doi.org/10.1655/Herpetologica-D-15-00042

Tingle, J. L., & Sherman, B. M. (2022). Scaling and relations of morphology with locomotor kinematics in the sidewinder rattlesnake Crotalus cerastes. Journal of Experimental Biology, 225(7), jeb243817. https://doi.org/10.1242/jeb.243817

Blomsten, P., Schuett, G. W., Höggren, M., & Clark, R. W. (2016). Fifteen consecutive years of successful reproduction in a captive female sidewinder (Crotalus cerastes). Herpetological Review, 47(2), 231–234. https://www.academia.edu/download/43375448/Blomsten_et_al_Sidewinder_Reproduction_HR_2016.pdf

Rautsaw, R. M., Hofmann, E. P., et al. (2019). Intraspecific sequence and gene expression variation contribute little to venom diversity in sidewinder rattlesnakes (Crotalus cerastes). Proceedings of the Royal Society B: Biological Sciences, 286(1902), 20190810. https://doi.org/10.1098/rspb.2019.0810

Webber, M. M., Glaudas, X., & Rodríguez-Robles, J. A. (2012). Do sidewinder rattlesnakes (Crotalus cerastes, Viperidae) cease feeding during the breeding season? Copeia, 2012(1), 100–105. https://doi.org/10.1643/CE-11-056

Leavitt, D. J., & Grimsley, A. A. (2019). Density, recapture probability, biomass, productivity, and population structure of sidewinders (Crotalus cerastes) in the Sonoran Desert of Arizona. Herpetology Notes, 12, 577–584. https://www.biotaxa.org/hn/article/view/35147/44449