SLITHERING SNAKE SKY ISLAND SNAKES - A SURPRISING SLITHER OF SPECIES

OK, so this is not Ethnobotany...but I do see plenty of incredible Sky Island Snakes while collecting and exploring for wild plants!

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.!

Not surprisingly these statistics pall in comparison to the 2500 to 3000 snake species that inhabit the entire planet. None-the-less, our Sky Island species span a wide range of sizes, shapes, and fascinating life histories well worth exploring. As with our more renowned diversity of birds, a relatively high percentage of our snake species barely enter into the U.S. and do so mostly or only in the Sky Islands. Thus, we harbor a snake fauna more typical of Mexico- Mexican Specialties if you will. Much of this diversity is owing to the same factors that render the entire region such a biodiversity hot-spot in general.

 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.

One of my more memorable Sky Islands snake encounters occurred several years ago. While meandering along the trails of our Nature Sanctuary it suddenly began pour rain. It was, after all, Monsoon season. Enjoying the coolness and keeping a sharp eye out for wildlife, I was arrested in my tracks by a small, but brilliantly colored snake which lay directly in my path. It too seemed to be lured out by the moisture. Quickly it sensed my presence and began a strange defensive behavior - namely forcing its cloaca (the common vent for bodily waste and reproduction) out in order to effect a popping sound. Although I had previously read about this behavior, it non-the-less produced the desired effect and startled me - enough time for the snake to disappear into the thick grass where I had first run across it.

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”!

RAVEN: CREATOR, TRICKSTER, BIG-BLACK BIRD

Chances are that if I say “Raven” you will conjure up some sort of coherent images of this iconic bird. Be it evil omen, portend of good luck, battle bird, poetic messenger (think Poe), or symbol of wilderness, the Raven rarely lurks in the background of the human imagination or in our beliefs. Instead it inspires, reviles, and even defiles us in ways that render it impossible to ignore or dismiss.

 Think of our language and how this bird has infiltrated the very way in which we communicate. Someone who we construe to be crazy can be said to be “stark raving mad’. Conversely, an attractive person may be ravishing. When we strongly desire something, we crave it, perhaps at a wild party commonly referred to as a rave, where we meet a striking lady with raven hair. Try to think of another species that has so colored our words and you may be hard-pressed. True, something strange can be fishy, but as with so many other animal-inspired words the allusion is a generic one. Of course, turnabout is fair play, so more than a few Ravens have been taught to speak some human words.

 Just so it’s clear, I’m specifically referring to the Common or Northern Raven (Corvus Corax) in this article. Though the world is endowed with a variety of beautiful species in the genus Corvus that are referred to as “Ravens”, the Raven that is familiar to most people in northern cultures is this species. It has a vast range that extends from the Arctic Circle down to the Jungles of Nicaragua and from the west coast of the U.S. to our eastern seaboard - being mostly absent from the prairie and southeastern states. It is also a Holactic species that lives in the Old World from Britain, throughout much of Europe and well into Asia, including northern Japan. Within this vast range the Raven occupies an astounding varieties of habitats, including tundra, grasslands, woodlands, deciduous forest, coniferous forest, tropical forest and chaparral. Lacking human persecution, it is the ultimate in adaptable birds

You can easily distinguish Ravens from superficially similar American Crows (also in the genus Corvus) by a number of anatomical and aural differences. Starting with the latter, a standard Raven contact call is a throaty “croak” (their specific latin epithet is a case of them uttering their own name, as they croak “coraaax”) while the equivalent American Crow vocalization is a harsh “caaaw”. Many other sounds help to identify and separate each species, making it relatively easy to tell them apart by vocalizations alone.

 Additionally, American Crows are much smaller than Common Ravens. They average around a pound in weight, depending upon the geographic population in question, while Ravens can surpass two pounds and even weigh as much as a Red-tailed Hawk! Crows have large beaks, while those of Ravens are relatively massive. Ravens sport a shag of feathers at the throat referred to as a beard that Crows lack. Ravens possess proportionately longer wings that allow them to glide and soar much more than their smaller, shorter-winged cousins. Also, the tail of a flying Crow appears squared off at the end while that of Ravens is wedge-shaped. If all of this sounds a bit confusing, simply remember that American Crows are not a normal component of our Sky Islands avifauna. They are mere vagrants in southeast Arizona, where Common Ravens are year-round residents. If you want to see a Crow in Arizona, then you have to travel up to Flagstaff, Prescott and other points North.

 The real corvid confusion arises when you realize that the Sky Islands harbor not one, but two species of Ravens! In addition to Corvus corax, Corvus cryptoleucus (the specific epithet meaning “hidden white”, referring to their light-colored feathers at the base of the neck that normally remain unseen, and which account for their former common name - White-necked Raven) the Chihuahuan Raven, is a relatively common bird in our area. Though there are a number of palpable differences between them, telling these two species apart is not always an mundane task.

 Common Ravens are quite a bit larger than their Chihuahuan cousins, averaging about a third again as heavy. The feathers covering the nasal area on the beak of a Chihuahuan Raven extend out further and their calls tend to be higher pitched. Further, they tend to nest in lower elevation sites in Arizona, especially in Mesquites and Soaptree Yuccas, whereas Common Ravens prefer higher nesting sites - often in cliffs or tall trees in forested areas. Finally, Chihuahuans can congregate in very large flocks - sometimes in the thousands - particularly at roosts. Commons tend to be, well, less common.

 All this said, if you see a lone bird - obviously a Raven - flying close overhead you may still be at odds as to which species you’re seeing. I try to judge size and calls, as well as habitat differences, but I’d be kidding you if I claimed that I could identify every Raven I see in the Sky Islands! Adding to the conundrum is the fact that the two species sometimes form communal roost sites during the non-breeding season. Keeping this identification puzzle in mind, I had a wonderful encounter with both species about a decade ago.

 While slowly driving along the eastern edge of the lofty Chiricahua Mountains I happened to spy a congregation of perhaps five Turkey Vultures at a road-killed Black-tailed Jackrabbit. Accompanying them were perhaps eight Ravens. Since both species would be relatively dwarfed by the Vultures, this provided no great clue as to their identity. As the Vultures easily dominated their fellow scavengers, who occasionally tried to sneak closer to the meal or to pull at a tempting tail feather, a new arrival swiftly solved the mystery. Flying just overhead of the melee was a Raven much larger than those below - a Common Raven. Juxtaposed next to each other, it was very easy indeed to separate the two species.

Beyond the “big, black bird” part, I would be remiss not to mention some of the roles that Common Ravens have played in human cultures across the enormous expanse where the two species overlap. Edgar Allen Poe could not have chosen a more fitting symbol of Nature to deliver a mournful message in his poem named after this ominous bird. Tracing back the thread of connectivity, it seems obvious that the English settlers of America brought over their dread of Ravens from Britain. This in turn was spawned by the fact that the Vikings - their often enemy - carried a Raven standard as their battle bird into often successful frays with the Brits. Thus, one man’s battle bird is another’s harbinger of death. 

Odin, the equivalent of Zues among the Vikings, had two special Ravens, Thought and Memory, that each day would set forth to discover the secrets of the world which they later would whisper only to him. This helped to account for his omnipotence. In fact, had the Viking’s original settlements on the eastern coast of Canada panned out, perhaps our national symbol would be a Raven, not a Bald Eagle. Going a step further, maybe the White House would instead be black! If these musings stir some sort of visceral and indignant patriotic thought, then ponder just how much hatred of Ravens has biased our culture against the color black!

 Leaving you that to consider, also keep in mind some of the numerous other roles the Raven has been cast into via its Homo sapiens consorts. In the Old Testament of the Bible, the first bird that Noah entrusted to find land was not a Dove, but a Raven. True to form, it simply flew off, never to return. The presumption is that it indeed located terra firma, but decided that telling humans was of no great consequence! Still, Ceylonese mariners often entrusted Ravens to find land while sailing in the briny deep of the Indian Ocean. Likewise, Ravens purportedly helped the Vikings to first locate Iceland. 

Some Native American cultures of the Pacific Northwest cast Raven into the dual roles of Creator and Trickster. As the former, Raven helped to bring humans into the world, sometimes placing the Sun in the Sky and bringing light to an otherwise perpetually black world. Indeed, the Bella Bella identified Raven as “One Whose Voice Is to Be Obeyed”. Conversely, the same Raven might well temporarily lose his beak while up to some crafty tomfoolery or sexual exploits in a different story by the same culture. The Koyukon people of Alaska historically entreated a passing Raven to “drop them a basket” as it passed overhead. Should the bird in question turn over while in flight, then the man or woman might expect some good fortune in the near future. It seems that the diametrically opposed roles of Creator and Trickster were easily shouldered by Raven!

 Closer to home, Athabaskan-speaking Apache - likely having migrated to the Southwest from Canada where even more “Raven-identifying” cultures prevailed - credited the Raven as having brought game animals into the world. This, no small feat given the supreme importance of hunting among these people. These few examples are but the proverbial tip of the iceberg when it comes to the myriad of associations between people and Ravens. For further reading, peruse In the Company of Crows and Ravens by Marzluff and Angell for an excellent overview of the topic.

 Truly, the Raven always seems to play a key role for humans, regardless of what it specifically represents. Given an intriguing hypothesis that Raven biologist Bernd Heinrich poses in his excellent books, Ravens in Winter and Mind of the Raven, one is left to ponder just how these charismatic birds see humans. Namely, Heinrich poses that Ravens, being the quintessential scavenger and a strong flier, often encounter large carcasses (say, a Deer) before other partakers of dead bodies. This poses a dilemma, as aside from the anus and the eyes, Ravens are normally unable to make any significant intrusions into the would-be meal.

Their notable vocal repertoire comes to the rescue, however! Using a very specific type of “recruitment call” that is apparently recognized by fellow, larger scavengers, Ravens attract Coyotes, Wolves, Bear, Wolverines, or even humans to the potential banquet. “Better to share in a feast than starve alone” seems to be their maxim. Heinrich even ponders the possibility that Ravens will alert predators to a living potential meal if the two are in close proximity. So, the next time a Raven makes riotous calls near you, please consider the following: is it trying to share a carcass with you, hoping that you kill something so that it can scavenge, or aspiring - via a more potent predator - to make you the meal?!