A Harlequin Romance

Color me captivated

by William W. Lamar

I seldom carry a cell phone because I dislike the bulk, the weight, and full pockets. They can certainly be handy, even life-saving; but the contraptions have also extracted a cost far too dear for the convenience they offer: our very souls. I tend to hold mine at arms’ length but make an exception when I am hiking in the East Texas forest near my home. I’m now long in the tooth, so carrying the phone is my “Help! I’ve fallen and can’t get up!” concession to probability. And so it was that during recent woods walk I took a call from a friend and colleague.

We were discussing a forthcoming book on coralsnakes in which I had done a lot of ghost editing, so I was carrying on about them and moaning about the workload. And that’s when one of those “What are the odds?” moments occurred.

As we spoke, a Texas Coralsnake (Micrurus tener) appeared by the trail! 

Texas Coralsnake, Micrurus tener, adult female, Smith County, Texas, USA. This is the specimen I found while talking on the phone about coralsnakes. Image: ©William W. Lamar 2024.

I interrupted myself, explaining that I was about to catch a coralsnake, so he naturally assumed it to be a joke. After all, they are seldom seen by humans because they tend to lead their lives concealed. And the chances of one magically appearing while being talked about? I gently laid the phone—still connected—on the ground, and maneuvered the thrashing snake into a cloth sack (yes, I carry a small one; it’s a holdover from my “Be Prepared” Boy Scout days). When I resumed our conversation, he chuckled and commented that he never again expected to be privy to hearing a coralsnake capture via cell phone.

I suggested he report it to the Guinness Book of World Records.

The snake, an adult female, was, like most of her kind, lovely. Bedecked with rings of brilliant red, black, and yellow, she looked more like a gaudy necklace dropped by some exotic princess than an animal, let alone anything reptilian. I carried her home for some photos, an activity that also gave me the chance to admire her more closely. In simpler times, facts about these snakes seemed to be incontrovertible. The colors, we were told, are aposematic; that is, their purpose being to warn us away, lest we fall victim to the venomous bite. And the venom, we were told, is neurotoxic (principally affecting the nervous system); drop-for-drop the most lethal of any snake in the U.S.A., although actually, that distinction goes to a tiny species of rattlesnake. The eyes, we were told, feature round pupils, just like all native harmless varieties (those of pitvipers are elliptical, like a cat’s eye). And it was believed that there was but a single species in the United States, with the exception of a distant cousin found in the Southwest.

Today we see things differently. The vivid (to us), contrasting colors likely play multiple roles. One might, admittedly, be aposematic, but only for potential predators with color vision. Humans showed up too late in the evolutionary scene to have much of an adaptive effect on snakes. Birds are a different story. Innate avoidance of coralsnake patterns by birds has been demonstrated under laboratory conditions, so there is something going on. That, of course, doesn’t stop us from being egocentric enough to think all of Nature’s phenomena are intended for humans; most aren’t. The bold colors and arrangements are also cryptic and disruptive, effectively breaking the snake’s profile visually into little pieces that are difficult to detect, especially on a sun-dappled forest floor. And a lot changes once that snake is in motion. Coralsnakes are not fast but they are surprisingly quick and jerky, and the jumble of bobbing spots that separate and coalesce when one is wriggling are potentially confusing to a predator...especially me. 

The red rings may make observation in moonlit conditions difficult, which could hamper an owl, for example. And the reds also tend to “vanish” under relatively slow motion; yet another optical illusion. So, when a coralsnake begins moving, the effect (for humans and probably most other critters) is of isolated, dancing spots of yellow. The contrasting black rings enhance this, and the red rings tend to “disappear” so a would-be predator is left to follow all the bouncing balls. It may be what is known as motion dazzle, flicker-fusion, or a little of each; it certainly makes them hard to grab.

The venom is quite toxic, and it does tend—to make a gross oversimplification—to act upon the central nervous system. Back in the day, we thought that merely possessing potent venom was sufficient indication of a snake’s dangerousness, so coralsnakes were assumed to be the worst of the worst. We now know that a lot more goes into that, such as having an elegant inoculation system and being able to deliver a deadly amount of venom. And there are behavioral and logistical considerations. For instance, are coralsnakes prone to mix it up with humans? Or do we encounter so few of them because they steadfastly avoid human contact?

Open mouth detail of a Western Ribbon Coralsnake, Micrurus helleri, Quebrada Grande, Río Sucusari, Loreto, Peru. Coralsnake fangs are permanently erect and when the mouth is closed they fit into corresponding cavities alongside the mandibular teeth. Image: ©William W. Lamar 2024.

Unlike those of venomous pitvipers, coralsnake fangs are not long and folding. They are short and erect, made for grabbing and chewing; which is what these reptiles do when capturing the snakes and lizards upon which they mostly feed. So, their fangs do not especially lend themselves to striking and injecting. Since coralsnakes have smallish venom glands they don’t carry a great quantity of venom; and the latter is so virulently effective at immobilizing prey that they don’t need a lot. The resultant smallish venom glands help to streamline the head for burrowing through leaf litter. This led to a simplistic reduction: Coralsnakes possess round heads while pitvipers feature triangular ones. That is actually more accurate with regard to the former than the latter. Oh, and the pupils...they are subcircular rather than round; but that is of more interest to morphologists than the lay public. Because they are small and the iris is dark, there’s not much detail to see in a coralsnake eye without benefit of a bright light and a good magnifying glass.

Above left, Harlequin Coralsnake, Micrurus fulvius, adult female, Homestead, Miami-Dade County, Florida, USA. Right, Texas Coralsnake, Micrurus tener, adult male, Bexar County, Texas, USA. The brilliant colors of these snakes are thought to convey a warning to imprudent predators. Images: ©William W. Lamar 2024.

Black Widow, Latrodectus mactans, with egg case. The hourglass warning coloration on the lower abdomen is universally recognized. Other closely related and equally venomous Latrodectus species exhibit similar red markings on their upper surfaces. Smith County, Texas USA. Image: ©William W. Lamar 2024.

The advent of DNA analysis, among other things, has allowed us to delve more deeply into Nature’s mysteries.  Now we know that there are two similar looking species of coralsnake populating the southern portion of the USA: The Harlequin- or Eastern Coralsnake (Micrurus fulvius) of the Deep South; and the Texas Coralsnake, which ranges from Arkansas and Louisiana across much of Texas and Mexico. In ancient times, the Mississippi River divided the population, and they have diverged from one another across the millennia.

Parsing the venom question a bit more leads one to distinguish between what might be termed deadly versus dangerous. Let me give you an example.

Drop-for-drop the venom of the infamous Black Widow Spider (Latrodectus mactans) is significantly more toxic than, say, that of the equally infamous Western Diamond-backed Rattlesnake (Crotalus atrox). So, does that mean it is the more dangerous of the two?  Bites from the former are uncommon, in part because the spiders are timid and in part because they are not especially efficient at biting humans. That is not to say they are unable to inflict a potentially lethal nip. But the rattler, abundant and often encountered by humans, is willing to defend itself, quite capable of delivering a harmful bite, and often does so. So, the former might best be termed deadly, while the latter is the more dangerous.

The same applies to coralsnakes; they are timid, seldom seen, and not adept at skewering humans with their fangs. They are deadly, but not especially dangerous. Few bites are inflicted on humans and most of those arise in a manner notably different than do those from pitvipers. The latter usually bite defensively if their space is invaded, or if trodden upon, or when someone tries to kill them. Coralsnake bites, however, tend to occur because the snakes are picked up and handled owing to their beauty. Perpetrators tend to be children, but also include nuts like me. The snakes’ garish rings, to us, would thus seem to be anything other than aposematic. The average human simply can’t leave the coralsnakes’ come-hither attraction alone. Likely those who avoid them do so simply because they are snakes, as opposed to adorned with warning colors.

Above left, a Pygmy Black-backed Coralsnake, Leptomicrurus scutiventris. Not all coralsnakes are ringed. Right, same Leptomicrurus scutiventris, underside, Padre Cocha, Loreto, Peru.  Coralsnakes that are dark dorsally are usually well marked on their bellies. Images: ©William W. Lamar 2024.

New World coralsnakes are a speciose group, with over eighty varieties currently recognized. They range from diminutive, foot-long snakes to hulking five-footers. Most are ringed; some bicolored, some tricolored, and some dorsally black. Some are semiaquatic but most are terrestrial and all are quasi-burrowers. That is, they noodle about in and under things. With the exception of the three varieties that occur in the U.S.A., all are restricted to Latin America. Complicating things, some species, like the Texas Coralsnake, not infrequently produce aberrant individuals. These feature pattern anomalies, including spotting or striping, or melanism; in some cases, all-black individuals have been observed.

The old rhyme, “Red and yellow kill a fellow/red and black venom lack” traditionally used to identify venomous coralsnakes and their mimics in the southern USA should not be relied on with these aberrant-colored individuals nor anywhere south of the border with Mexico.

An aberrantly patterned Eastern Variable Coralsnake, Micrurus apiatus, with saddle markings and incomplete bands along its midsection. Atlántida Department, Honduras. Some Chiapan, Yucatán Peninsular, and northern Guatemalan forms of this species are almost entirely red, lack black markings, and are also absent yellow other than one band across their heads and a few rings on their tails. Image: ©William W. Lamar 2024.

Certain populations of Langsdorff's Coralsnake, Micrurus langsdorffi, forego black rings entirely. Caucho Caño, Loreto, Peru. Image: ©William W. Lamar 2024.

A Western Ribbon Coralsnake, Micrurus helleri, engaged in a self-mimicry display, Río Samiria, Loreto, Peru. Note that, like many venomous coralsnakes occurring outside of the USA, the vivid red rings in this species are bordered by black. Image: © William W. Lamar 2024.

The third species of venomous coralsnake that occurs in the USA, the Arizona Coralsnake, Micruroides e. euryxanthus, ranges from western Mexico to northwestern Arizona then east to southwestern New Mexico. Arizona Coralsnakes practice self-mimicry with a twist; they “fart” audibly and noisomely while curling their tails and everting their cloacae. Vicinity of Yarnell, Yavapai County, Arizona, USA. Image: ©Rick C. West 2024.

When I detained the coralsnake on my hike, she immediately flattened herself, curled and raised head and tail, and began to convulsively wave them back and forth. This tactic was traditionally presumed to be a tail display, and it was long thought to distract from potentially damaging attacks to the snake’s fragile head. Were this correct, however, specimens with scarring on the tail would be expected. Examination of dozens of museum specimens shows that’s not the case. And how about all the head wagging; what are they up to? An enterprising researcher labeled the activity self-mimicry. That is, the snake endeavors to appear not as one but as two, something that engenders confusion on the part of a predator and thus a chance for escape.

These displays are often accompanied by alarmed coralsnakes hiding their heads under foliage, leaf litter, or their own bodies while elevating their tails. The tail-alone part of a self-mimicry display intrigues because it is not employed to draw attacks since tail scarring is generally absent in coralsnakes. In my experience the intensity of these displays escalates in proportion to the perceived threat, culminating in the head playing its part at the same time as the tail, during which the snake begins to crab-crawl away using its mid-body for traction.

Self-mimicry is now known to be a common defensive response in all three New World coralsnake genera. Leptomicrurus species may also react to threats by exposing expanses of brightly-banded ventral surfaces when they flip the posterior one-third of their bodies over.

Narducci's Black-backed Coralsnake, Leptomicrurus narduccii, in a self-mimicry display at Jatun Sacha, Napo Province, Ecuador exposing the brilliant dazzle colors on the underside of its tail. Image: ©William W. Lamar 2024.

Above left, a Common Aquatic Coralsnake, Micrurus surinamensis  Yanamono, Loreto, Peru. Some coralsnake species like this one spend most of their lives in the water. Right, the snake is engaging in a self-mimicry display wherein it simultaneously moves head and tail so as to appear to be not one but two snakes. Images: ©William W. Lamar 2024.

A particularly vividly-colored Common Aquatic Coralsnake engaged in self-mimicry, with its body flattened, and its tail elevated and coiled. Notice also that its head is tucked tightly against the neck, which is also part of the defensive display in many coralsnake species. Finca El Acuario, Las Mercedes, Villavicencio, Meta Department, Colombia. Image: ©Juan Manuel Renjifo, ©William W. Lamar, and Cornell University Press 2024. Used with permission.

Slender Coralsnake, Micrurus filiformis, Pamopetá, Vaupés, Colombia. This is the same tiny snake that successfully defended itself with self-mimicry against the Gray-winged Trumpeter discussed below. Image: ©William W. Lamar 2024.

Gray-winged Trumpeter Psophia crepitans. Bajo Río Sucusari, Loreto, Peru. Image: ©William W. Lamar 2024.

Many years ago in Amazonian Colombia I happened to see this phenomenon at work.

A powerful rapacious bird called a Gray-winged Trumpeter (Psophia crepitans) confronted a tiny Slender Coralsnake (Micrurus filiformis). It was not in the least bit inhibited by the brilliant colors of the snake. The bird was a free-ranging pet of one of the Karapanã people in whose village I was staying. Over several weeks I had witnessed it overpower and consume lizards, rodents, snakes, and pretty much anything it encountered. It fought daily with a village dog and invariably won. But the diminutive coralsnake, frantically engaging in self-mimicry, had the big bird totally flummoxed. Indecisive, it alternately stared at one end or the other of the snake; meanwhile, the latter was crab-crawling with the middle of its body into the leaves. Did the bird see two snakes and decide that was one too many? Or did the bizarre movements amplify and enhance the crazy juxtaposition of all the cream rings, creating a kind of double optical illusion. I interrupted the party and caught the snake but was left with the impression that the little reptile would have escaped the Trumpeter.

The day after photographing the Texas Coralsnake I returned to the spot in the forest where I had found her. I untied the cloth sack, laid it onto the ground and slowly slid it off. She remained quiet, her tongue flicking actively as she sensed familiar surroundings.  Eventually she began crawling away in the leaf litter.

Then I remembered that, like last time, I had laid my phone aside in the middle of talking to my friend. When I resumed our conversation he chuckled and commented that he never again expected to be privy to hearing a coralsnake release via cell phone. I suggested he also report that to the Guinness Book of World Records.

Epilogue : I’ve hiked that trail frequently during the past five years and that is the only coralsnake I have seen there. 

What are the odds?

Texas Coralsnake, Micrurus tener, yawning. Image: ©William W. Lamar 2024.

Mimics

Two color morphs of the Variegated False Coralsnake, Pliocercus elapoides diastema, at Finca El Faro, El Palmar, Quetzaltengo Department, Guatemala. Variegated False Coralsnakes at this site closely mimic two differently patterned venomous coralsnake species that occur there in sympatry: the Zunil Coralsnake, Micrurus nigrocinctus zunilensis, and the Long-banded Coralsnake, Micrurus latifasciatus. Image: ©William W. Lamar 2024.

Above, two widespread colubrid snake genera that are well-known for having many varieties that mimic venomous coralsnakes that occur with them in nature. Left, Blanchard’s Milksnake, Lampropeltis abnorma (blanchardi), Mérida, Yucatán State, Mexico. Right, Aesculapian False Coralsnake, Erythrolamprus aesculapii, Tigüino, Pastaza, Ecuador. Images: ©William W. Lamar 2024.

Non-venomous coralsnake mimics are incredibly diverse in color and most share ranges of the three venomous genera throughout North and South America. Above, the Scarlet Snake, Cemophora coccinea, is one mimic that also occurs into the northeastern and central USA states where its venomous models are absent. Perkinston, Stone County, Mississippi, USA. Image: ©William W. Lamar 2024.

All content ©Exotica Esoterica® LLC 2024, ©William W. Lamar 2024, and ©Rick C. West 2024.