Trimeresurus albolabris – White-lipped Pit Viper
The most widespread green pit viper species in Thailand is the Trimeresurus albolabris, known as the White-lipped Pit Viper. It is found throughout the whole country. Due to its preference to the lower elevations and adaptability to disturbed habitats, this is the most commonly encountered viper especially near human habitation. There is some variety depending on locality, and most likely the species will be split up in multiple species in the future.
|Dangerous?||Dangerous, causes severe injuries to the bite site, and in few cases leading to death; front-fanged, foldable hollow fangs, potent venom; these snakes rely on their camouflage so are not likely to flee. Which means, in the unfortunate case you don’t see it, but unknowingly grab it, it may decide to bite.|
|Length||60 – 80cm|
|Diet||Mostly rodents, birds, and frogs|
|How easy to find||Widespread, not uncommon even in people’s gardens. In the right locations relatively easy to find.|
|Best time of year||We have seen this species all year round, but wet season seems the best time.|
|Best time of day||Like most green pit vipers, they can basically be found anytime of day. But they normally get active when darkness falls and are easier to spot with a torch in the dark because the body color pops out in the light from the surrounding green vegetation.|
|Threats||Does not seem to be under threat, though my guess is that habitat fragmentation could potentially cause numbers to drop over time.|
The Trimeresurus albolabris is a relatively slender tree viper with large triangular-shaped head. The body is green, normally brighter lime green in females than in males. The tail is red. The red starts from the top ridge above the vent and towards the tip the red encircles the entire tail. Males normally have a white line starting from the cheeks following the ventrals. In some populations the males have a red ventral line next to the white line. Females might have a white, yellow or absent ventral line. Normally the females have no line on the head. Ventrals vary from green/ yellow to yellow/ white. Eye-color is usually gold, though in some populations deep red (potentially these will later be split up as a separate species.).
(Click an image to enlarge and open the gallery view)
For someone not familiar with this genus, many species will look very similar, but upon close inspection the differences become more clear. We won’t mention all potentially confusing species below, but will mention one that seems to prefer low elevation as well.
- Trimeresurus macrops – Large-eyed Pit Viper shares similar habitats and has the same coloration on the tail. They might have the same white line on the head and along the ventrals, though this line might be more bluish in certain individuals/ populations. The eye is more true yellow and slightly larger. The overall color tends more towards a blue hue of green. Also the lower jaw is generally bluish white.
In my experience the White-lipped Pit Vipers are a bit more active hunters than most other green vipers in Thailand. Though also they can be found in the more typical s-shape ambush position on low branches waiting for prey.
These Trimeresurus albolabris vipers (I suppose like most snakes, but at least with this species I have personally observed it) seem to know their way around their homerange. When I relocated a specimen out of the garden of some family in Eastern Thailand the specimen was back at the exact same spot a day after. I only had moved it for like 20m in a bush outside of the garden but anyway. I repeated this once more, this time moved it maybe 30 – 40m. And again a day later it was back at her favorite spot. This time less visible, so I decided to leave it there.
Radiotelemetry research with species like the King Cobra have shown the same results and therefore it is recommended to never relocate a snake too far from the place it was found. It will find its way, and will likely move around unseen for months before someone encounters it again.
Range & habitat
The Trimeresurus albolabris is normally found at lower elevations. The books usually say up to 500m asl, though I can not recall seeing any above 400m asl. Secondary growth, mixed dry deciduous forest, even narrow strips of vegetations along roadsides or between open crop fields, and near streams are all habitats where the White-lipped Pit Vipers can be found. Possibly close to human habitation.
Trimeresurus albolabris is likely to be a complex species which at some point will likely be split into several species within Thailand.
How to find this species in Thailand?
Even though I have found them in daytime, night time is definitely the better time to look for them simply because like all the green vipers their bodies seem to ‘light up’ when you point a flashlight on them. This makes the stand out more clearly from the green vegetation. I think In most cases I have found the White-lipped Pit Vipers quite close to the ground, in most cases not higher than 1m, but occasionally they might climb a bit higher up. A good place to start searching is near water ways with some dense vegetation. It depends a bit on the region, but as soon as it starts to get more humid, the chances seem to increase.