A Gila Monster out and about on a warm Spring day that I found a while back.
At that time, more than a decade ago, I knew relatively little about the day-to-day habits of these animals. Finding one was more a matter of luck than anything else. But, I’ve since learned a lot, and these are now often a higher observation count in a day than I’d had seen in an entire year.
Recommended reading, if you can find it:
Biology of Gila Monsters and Beaded Lizards — Daniel D. Beck (UC Press)
A large male Western Diamondback Rattlesnake cruising through dense vegetation, on the lookout for others that may be near. At this higher elevation den in the late fall, the females are already tucked into rock crevices and caves. All that remain on the surface are the largest males, patrolling for rivals, and getting into the occasional fight. This one finished its loop and settled back into the sunny spot it prefers for awhile, before doing it all again about an hour later. Why wait until spring to fight for the good spot, when you can do it in the fall?
Switak’s Banded Gecko that we found in Baja California Sur, Mexico. These are closely related to the Western Banded Geckos we’re all familiar with here in Arizona, with some notable differences. The most obvious being its larger size, this one about the size of a small mouse. When seen in this boulder field, they hop from rock to rock and disappear (or try to, anyway) or wag their tails in a defensive display.
1. Murray, S. S., Dugan, E. A., Clause, A. G., & Mills, A. M. (2024). Maximum size and mass of Switak’s Banded Gecko, Coleonyx switaki (Murphy, 1974). Herpetology Notes.
2. Lovich, R. E., Grismer, L. L., & Danemann, G. (2009). Conservation status of the herpetofauna of Baja California, México and associated islands in the Sea of Cortez and Pacific Ocean. Herpetological Conservation and Biology, 4(3), 386–405.
3. Lemm, J. (2023). Field guide to amphibians and reptiles of the San Diego region. University of California Press.
A young Blacktailed Rattlesnake from the eastern end of Arizona. While not as sharply contrasted as the population from just south in the Sky Islands, I personally like the clean, subtle tones and velvety appearance of these snakes in this area.
A relatively large Aquatic Coralsnake (Micrurus surinamensis) found near camp in Peru. These snakes are relatively common, found in the swale alongside the river and smaller drainages, where they’re on the hunt for eels and other fish, and the occasional other snake. Compared to other coralsnakes, they are heavy-bodied, with a wide head and short tail.
A bear and I look at each other across a ravine, likely doing similar things in the area … looking for small vertebrates.
A common sight around waterways south of the US are the cat-eyed snakes; mildly venomous, cat-eyed snakes (Leptodeira sp.). However, they do make it into the country in one small area of extreme south Texas. We found this Northern Cat-eyed Snake (Leptodeira septentrionalis) there several years ago. For friends in Arizona, these are most closely related to the nightsnakes (Hypsiglena sp.), both in form and lineage.
Vidal, N., Dewynter, M., & Gower, D. J. (2010). Dissecting the major American snake radiation: A molecular phylogeny of the Dipsadidae Bonaparte (Serpentes, Caenophidia). Comptes Rendus Biologies, 333(1), 48–55. https://doi.org/10.1016/j.crvi.2009.11.003
A young Sonoran Whipsnake near Phoenix. These snakes are extremely fast, daytime hunters that go after everything from lizards to other snakes. Most encounters people will have with them are as a blue-grey blur disappearing into the bushes, where it will seem to just teleport to another dimension if you try and find it.
Despite being incredibly easy to observe in surrounding mountain ranges, the Southwestern Speckled Rattlesnakes in the Sierra Estrella just southwest of Phoenix are harder to spot. They’re likely just as common, but the steep terrain and majority of prime geology for the species being inaccessible reservation land make it a challenge to see one. Kris Haas spotted this pretty one way up mountain.
