Tagalog legend tells us that Bathala once summoned all snakes to partake in a jar full of venom so that they could arm their fangs with the toxic soup with which to kill their prey and protect themselves from anyone who wished to do them harm. Dahong-palay (and his orthographical variant dahunpalay), who woke up late, arrived with the deadly liquid already consumed by all the other snakes. He instead resorted to crawling inside the jar where his skin absorbed the residue, making him exceptional for being venomous through skin contact instead of through bite.
A touch from a provoker would be enough to cause death. For this reason, the dahong-palay became one of the most feared of all forest denizens and a sighting is enough to send anyone scampering away, lest the dahong palay, with all the malice it could possibly conjure, chase the intruder and brush his skin in a fatal caress.
Ahaetulla prasina and their subspecies are strictly tied to forests. Whereas other arboreal snakes from the genera Dendrelaphis, Dryophiops, Chrysopele, and Genyosoma are apt to be found within human habitation. Ahaetulla appears acutely intolerant of human presence and activities. It is for this reason that these snakes often escape human persecution, a grim fate that is ever-present for snakes in a nation populated by deliberately ophidiophobic masses.
However, the continued habitat destruction and conversion of lowland forests have greatly diminished suitable habitats for these snakes and myriad other species.
Deductions about the dahong-palay
But, as with all legends, this one has failed to stand up to modern-day understanding of nature, snakes included, because except for the tiger keelback (Rhabdophis tigrinus), none are know to possess poison through their skin. The tiger keelback is not found in the Philippines, thus the snake cannot be the dreaded dahong-palay of legend. Furthermore, merely touching these snakes is harmless, unless one touches the nape region (where it stores toad toxins sequesters from their warty anuran prey) and licks their fingers afterward.
In the Philippines, four snakes are predominantly green enough to stand as the mythical dahong-palay candidates: two species of vipers (Trimeresurus flavomaculatus and Tropidolaemus subannulatus), the green ratsnake (Gonyosoma axycephala), and the vine snake (Ahaetulla prasina). The first two are venomous, the third is non-venomous, and the last is very mildly venomous. However, since the legend made no mention of the dahong-palay’s toxic bite, we can rule out the vipers, leaving the two as possible contenders.
And if we go beyond the considerations of color and take into account the imagery invoked by the term ‘dahong-palay’, then we will have arrived at the only plausible entrant: the vine snake. This snake is extremely slender and think as a grass leaf with a pointed snout that evokes a rice leaf’s tip. And, of course, the vine snake is green.
Still, other snakes have also been confused as the dahong-palay, and these include other slender snakes, mainly involving the non-venomous bronzebacks (Dendrelaphis) and the flying snakes (Chrysopelea) whose venom is ridiculously weak to be practically non-existent. Bronzebacks are known in Tagalog as “talbos-tubo“; I do not know what the Filipino term for flying snakes is, but knowing how common names work in mysterious ways, it may as well be “talbos-tubo” too and yes, even “dahong-palay.”
Indeed, any other slender snake is qualified to be granted any of these two names and this illustrates why the use of common names are often of very little assistance in identifying snake species. Scientific names, ladies and gents, allow us to speak the same language.
Ahaetulla prasina is a widespread species that has been recorded from Bhutan, northeastern India, Bangladesh, China, Myanmar, Thailand, Laos, Cambodia, Vietnam, Peninsular Malaysia, Singapore, Sumatra, Borneo, Java, Bali, and several other islands in Indonesia. In the Philippines, it is represented by three subspecies, prasina (Palawan), preocularis (most of the Philippines), and suluensis (Sulu Archipelago).
As a rear-fanged snakes, the fangs of Ahaetulla are unsurprisingly situated at the rear of the upper maxilla, located beneath the posterior edge of the eye. However, positioned at the middle of the upper maxilla are one to two enlarged, fang-like teeth.
The vertebral scales are trapezoidal in shape; this is a feature seen in only a very small number of snake genera around the world. The snakes average lengths of about 1.5 meters, with the females being longer than the males.
Subspecies preocularis is separated from subspecies prasina (Ahaetulla prasina subsp. prasina) in having a single anal scale and two preocular scales (versus one), and the internasal scales being not in contact with the labial (lip) scales. Rather obviously, this is the snake that figures in the Tagalog dahong-palay narrative as this is the subspecies that is present in the Katagalugan region.
The snakes are most commonly green throughout their known range, although Negros has green and red forms, Panay has the red form, and southern Luzon has both green and yellow forms. Whatever the color scheme is, there is always a pale lateral stripe separating the ventral scales from the rest of the body.
The head of the Ahaetulla is distinct from the neck, terminating in a pointed rostrum; sufficient to say, the head of these snakes reminds one of a spearhead than anything else, albeit green. The slender body is laterally compressed with smooth scales and the tail is very long and prehensile.
Years ago, I read somewhere that Ahaetulla is the only genus of snake whose members see in 3D. All other snakes see the world in 2D, as if staring at an image in a flat sheet of paper.
In captivity, these snakes will set their sights on a moving prey then lock on even if it has stopped moving. However, the target should move again before the snake delivers a strike.
The sinuous advance of an Ahaetulla about to strike is something to be marveled at: The head stays roughly in one spot while the body advances slowly forward, resulting in multiple S-curves beginning from neck to about midbody. Whether preparing to attack or reaching out for a distant branch, the form is unmistakable.
Venom in Ahaetulla prasina subsp. preocularis is very weak. Comparable to my observations in other rear-fanged snakes such as the flying snakes and I (known by the Tagalogs as for their propensity for frogs), I am yet to observe one ingesting a fully dead prey which suggests that venom may be of very little role in quieting struggling quarry.
It seems much more likely that the enlarged non-venom conducting fangs in the middle of the upper maxilla delivers the most impairment by puncturing the skin of prey and perhaps damaging at least some of the internal organs.
Nevertheless, as mentioned before, observations reveal that prey are always swallowed while still alive. I have been bitten thrice by these snakes in the past, and unlike the typical nip delivered by many other snakes when defending themselves, the dahong-palay resorts to chewing. This behavior is seen in other rear-fanged snakes, famously in the dangerously venomous boomslang (Dispholidus typus) of South Africa.
The genus consists of strictly diurnal snakes who prefer to forage on shrubs and tree branches, commonly about two meters above the ground. The coloration allows them to blend cryptically with surrounding vegetation, and the snakes move so deliberately that they often go unnoticed, whether by potential prey or predators.
Venom in vain
Knowing that the venom is of little significance, I have in all occasions allowed the indignant serpents to hang on for as long as they can, and in all instances, no skin reactions were severe enough to warrant a quick trip to the nearest hospital. The bite sites exhibited only some itching and very minor swelling that subsided in about half an hour.
I must admit, however, that the bite is still rather disconcerting, no doubt because of their large fangs.
Ahaetulla are characteristically calm snakes that go about their daily lives as if in a constant state of zen. They move around very slowly except when avoiding perceived predators; a larger animal in pursuit of a vine snake will only see a blur of green (or red or yellow, depending on where they are) sliding like greased spaghetti and gone the next second.
Still, these snakes will sometimes stand their ground and engage in a threat display consisting of multiple S-curves and inflation of the body, resulting in the exposure of rather startling diagonal dashes of bluish-white and black on the interstitial skin while the pointed tongue is extended in a practically immobile manner towards the intruder.
When grabbed, they will not hesitate to deliver a bite if escape is hindered. Compared to the repeated, staccato defensive bites of flying snakes, vine snakes bite more like bronzebacks, but with more painful results due to the mid-jaw fangs. Nevertheless, they can be handled and photographed without one getting bitten if sudden and threatening movements are avoided.
Vine snakes are predators primarily of lizards such as geckos and skinks, and will also take frogs if the opportunity arises. Hopeful keepers in both North America and Europe have tried switching the snakes to a rodent-based diet using hopper mice, to no avail. Compared to the other diurnal and arboreal snakes mentioned in this article, Ahaetulla seems to require fewer feedings due to them being less active and more deliberate in their movements. Metabolism still is rather high, and a midbody bulge from a large-sized lizard meal will have vanished in about two days. Despite the menacing reputation bestowed by the legend, dahong-palay is far less sinister in reality and, if at all, can even be accused of being so innocuous to be practically invisible. A true forest denizen, these graceful snakes can totally command your awe if you come across one but it is only possible if you remove all fear and prejudice against them – including a belief in their mythical origin.
This appeared in Animal Scene magazine’s September-October 2020 issue.
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