Despite the plethora of wildlife encounters we are collectively graced with in our hyper-diverse Sky Islands Region those involving snakes tend to hold a special place in our realm of Nature experiences. If asked to recount the last run-in with a White-winged Dove, we would be forgiven a large pregnant pause or even a total lapse of memory. A similar query about our last snake encounter may well result in a more vivid recall of the event. It seems that our relationship with snakes - venomous and benign species alike - strikes a chord so primal that we have little trouble reliving the experience.
This makes sense when you consider that for the vast majority of human existence we were at a much greater risk of death due to a bite from a venomous snake. This, combined with the relative paucity of snake encounters - owing to their stealthy nature aimed at securing food and avoiding becoming food - may well explain why we remember our tete’s with them so vividly.
Perhaps the last ingredient in this semi-Sonoran saurian psyche saga is the great diversity of snake species that we are blessed to have in the Sky Islands. [On a quick side note, if you found yourself questioning my use of the word “blessed”, then you may have just sorted yourself out as a “snake -phobic” person rather then a “Snake-o-phile” the latter of which I am one.] We have more snake species than any other area in North America north of Mexico. About 45 species reside within the Sky Islands Region out of a total of 52 in all of Arizona. Compared to the 44 species native to all of Florida - a state that dips into the subtropics - and you start to get the idea that we are indeed “snake central”. In fact, our 45 species represent approximately 36% of all of the snake species found in the U.S.!
Namely, the Sky Islands include wide range of elevations (from about 1800’ to over 10,000’) at a relatively low latitude (approximately 32 degrees North) where a stepping-stone arrangement of tall, isolated mountains spans the temperate (Rocky Mountains) and tropical (Sierra Madres) zones, as well as 2 deserts (the Sonoran and the Chihuahuan). As you climb any of the mountain “islands’ - isolated from one another by foreboding expanses dry and searing deserts and grasslands - temperatures plummet, while precipitation increases. This results in a sort of “plant community ladder” that accommodates our various snake species. Accordingly, each snake species inhabits only those plant communities with which it has co-evolved. Some species are generalists and can lurk within a wide range of habitats, while others are confined to only a narrow zone or area where they can meet all of their daily needs.
Now to the cast of characters that collectively comprises our crawling colubrids, reclusive rattlers, and beyond.
Our Mexican Specialty snakes include a very strange one indeed and one which I have yet to encounter. The surreal-looking Brown Vine Snake (Oxybelis aenus) lives up to its moniker, as it mimics a generic vine strewn in a tree. Inhabiting mainly Madrean Evergreen Woodland, this species only enters the U.S. in a few ranges - the Atascosas, Pajaritos, and Patagonia Mountains. There it glides through trees and shrubs in search of its main prey, lizards. These it subdues with a venom delivered with grooved rear teeth. Despite its long length - up to 60” - and potent reptilian venom this species is one of a number of rear-fanged snakes that is harmless to humans. In fact, given its superb camouflage, you would indeed be fortunate to encounter this species during an entire lifetime wandering the wilds of the Sky Islands!
Another other-worldly snake might well be mistaken for a large Earthworm. The New Mexico Threadsnake (Leptotyphlops dissectus) indeed appears like a large segmented worm, as it grows up to nearly 12” in length. It hunts invertebrates, primarily ants and termites, in Chihuahuan Desertscrub, Grasslands, and Madrean Evergreen Woodland. This is another species that you would be lucky to encounter since it is distinctly fossorial. In other words, it lives underground and beneath surface objects. All of this is unique enough, but what truly sets the New Mexico Threadsnake and its close relatives apart is that small owls capture them unharmed, later releasing them in their nests to apparently dine upon troublesome ectoparasites (think lice...)! How this behavior evolved and why the owls don’t simply dine upon these hapless, diminutive snakes is indeed a perplexing mystery.
The final entry in our borderlands snake oddities is the more familiar, yet no less bizarre, Sonoran Coralsnake (Micruroides euryxanthus). Many people seem to know the somewhat familiar phrase “red on yella’ can kill a fella, red on black good for jack” or some variation thereof. This saying sadly falls short in describing some Coralsnake mimics unfortunately. The Sonoran Shovel-nosed Snake (Chionactis palarostris), which barely enters into the U.S. at Organ Pipe Cactus National Monument, has red bands surrounded by yellowish-white ones. So too does the wider spread Western Shovel-nosed Snake (C occipitalis). The saying does help when sorting out Coralsnakes from the various Kingsnakes (Lampropeltis spp.) who indeed sport red bands bordered by black.
Got all that? No worries if you fail a field test for Coralsnakes are rarely encountered - I’ve seen two in my life - and are so small that you would likely have to pick one up in order for their tiny heads to deliver any venom - though they rarely attempt to bite. Even then, they would probably have to gnaw on you a bit because unlike Rattlesnakes they lack hypodermic-like fangs with which to deliver their toxins. Instead they chew on you much in the fashion of a Gila Monster. If you feel that you would like a Darwin award (“out of the gene pool!”) then indeed pick one up, as their venom contains potent neurotoxins which potentially could be fatal.
Time and space are by far too short for me to expound upon our reptilian brethren as much as I would like to, though I will leave you with a few parting thoughts to ponder. First of all, if you are at least partially snake phobic and live in southeast Arizona, then you live in the wrong area! Given our snake diversity and the presence of about 10 highly venomous species (the aforementioned Coralsnake, as well as 9 species of Rattlesnakes) your chances of having a interlude with these slithering saurians is indeed higher than any other place in the U.S. Further, many people fail to distinguish various species of snakes, classing them all as undesirable vermin. Nothing could be further from the truth.
Consider a world without snakes, and you must then imagine one overrun with rodents and other common snake prey. Cliche as it is, snakes along with a host of other predators, help to keep Nature in a sort of fluid and ever-changing balance. My advice, then, is to get over the fact that they lack legs (snakes are essentially lizards who have evolved to have no legs) as well as the bad rap that they carry from the Garden of Eden myth. Instead, revel in their diversity, praise them for their ecological services, and (as one of our first U.S. flags entreated) “Don’t Tread on Me”!
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