10 Snakes Of Taiwan, From Rare To Common

 

 

1	Black odd-scaled snake

This harmless species mainly lives in mountainous areas of Taiwan at 1000-2000 metres, rather than the western lowlands. The black-scaled odd snake has no quarrel with humans and coexists with local villagers peacefully. 

Black-scaled odd snakes are endemic to Taiwan, occurring nowhere else. Mountain forest floors are their base, where they seek refuge in decaying pant matter and stone cracks. A great ID feature is its round, cartoon character eyes. Achalinus niger has round pupils, but because the iris is jet black too, everything blends together into a black orb. Their head is indistinct from the neck, carrying on like a tube.

Black-scaled odd snakes are non-venomous, and reports of bites are a mere trickle. They reach a maximum of 80cm and have shimmering iridescent colours under torchlight. While sightings are plentiful across Taiwan, and they’re far from rare, black-scaled odd snakes are poorly researched. Earthworms, slugs or frogs are believed to be its staple foodstuffs. They’re an egg-laying species, which produces roughly 7 eggs of 1x2cm dimensions. The wider Achalinus family has 26 members, ranging from southern China to Vietnam.

 

 

2	Taiwan pitviper

One of 5 pitvipers native to Taiwan. The Taiwan pitviper (Trimeresurus gracilis) is a particular high altitude lover, appearing only at 2000 metres or higher. Consequently, it contributes little to the island’s overall snakebite statistics. This species reaches a maximum of 60cm, and has a bulky head, and usually brown patterns. 

Trimeresurus gracilis venom lacks neurotoxins, and instead contains 40.3% metalloproteinases. These cause both local necrosis and spontaneous haemorrhaging by degrading collagen in blood vessel linings. No specific antivenom for the Taiwan pitviper exists. Until 2022, there were no detailed bite reports either. Two 25 year old women suffered bites, and the symptoms were nasty: the first experienced pain and swelling to her shoulder, and haemorrhagic bullae surrounding the bite wound. When an antivenom for the Taiwanese habu and Stejneger’s viper was administered, it reversed a swathe of the effects, but not all. She received the antivenom late, and her finger was left permanently and irreversibly bent.

The second victim was bitten on the right index finger, and received antivenom within 1 hour. Still, the swelling passed her elbow by four hours, and the forearm within nine hours, after which scientists pumped in more antivenom. Because she was treated swiftly, this victim made a full recovery. Trimeresurus gracilis is a great reason to be cautious in Taiwan’s mountains. 

 

 

3	Big-eyed ratsnake

One of Taiwan’s longest snakes, at a maximum of 220cm. This species is famous not just for its large eyes, compared to their Ptyas cousins (e.g. the oriental ratsnake of Thailand), but their extreme speed. According to many sources, Ptyas dhumnades is the fastest snake species in Asia. When flustered, they can vanish into the undergrowth in a heartbeat. If cornered, they’ll slither and jerk around in an erratic manner.

Big-eyed ratsnakes inhabit most of Taiwan, usually below 1800 metres. Further afield, they inhabit a swathe of China, even reaching Beijing to the north. Big-eyed ratsnakes tend to be grey in colour, with no bright, neon scales. There’s often a bright stripe down their spine, but it’s their exceptionally fast and whippy speed that makes Ptyas dhumnades stand out. It’s rare for this species to bite.

While they mainly stick to the ground, this species ventures onto branches during hunting expeditions. Ptyas dhumnades is a confirmed egg eater, snatching eggs of the Chinese sparrowhawk and black-throated bushtit from their nests. As juveniles, they have to watch out for Futsung wolf snakes, which were confirmed as a predator in 2010. Another predator is the Taiwan stink snake. Chinese people hunt this snake’s meat and use it as medicine for leprosy. Fortunately, it’s so fast that they probably fail a large portion of the time.

 

 

4	Kelung catsnake

The Boiga catsnake family is huge, with 38 members, but this is the only species to inhabit Taiwan. The Kelung catsnake is the most arboreal, or branch-dwelling snake of Taiwan. They can be found in forests across the whole island, except the highest central mountains over 1000 metres.

Kelung catsnakes measure up to 160cm and have bulging eyes and vertical pupils, as the catsnake name suggests. Their venom isn’t especially deadly, but this is an irritable species which won’t hesitate to lunge at intruders from a branch.

Their foes in the Taiwanese wilds include the many-banded krait, a nemesis with a paralysing neurotoxic venom. The catsnake was observed with its mouth already in its predator’s mouth, attempting to wrap its lower body around leaves, and then the krait’s body, as the krait dragged it away. Despite this, the catsnake was sucked ever further down, being fully swallowed 13 minutes after the scientists arrived. Kelung catsnakes themselves are the top bird egg raider of Taiwan, including eggs of fairy pittas, dusky fulvettas and grey-cheeked fulvettas. A 2015 study confirmed that they were the top nest raider among 8 Taiwanese snakes tested.

 

 

5	Taiwanese habu

Probably the Taiwanese snake responsible for the most snakebites. This is a medium sized viper, with a maximum of 112cm in males, and 116cm in females. Taiwanese habus inhabit all of Taiwan except the highly mountainous centre. There’s the most aggressive Taiwanese pitviper and will even lunge at moving shadows. This is a bogeyman which lurks in the dark rooms of abandoned houses, while typical habitats include farmlands, hillsides, forests and shrubby areas.

Firstly, a study covered 4647 Taiwanese snakes from 2005 to 2009. Two snakes accounted for 71.78% of bites: the Taiwanese habu and Stejneger’s viper. Chinese cobras and many-banded kraits accounted for 19.21% collectively, while the Chinese moccasin (D. acutus) caused just 0.73%.

A 2009-2016 study delved to the species level, involving 125 victims from northern Taiwan. 50% were caused by the Taiwanese habu, followed by 7% from Stejneger’s viper. Taiwanese habus also caused the most severe soft tissue damage, with more patients requiring surgery. Generally, neurotoxic symptoms are lacking, and swelling and haemorrhaging predominate, with painful blisters. Victims usually survive but can be left with deformities. Luckily, a dedicated Taiwanese habu antivenom is available.

 

 

6	Blue-lipped sea krait

In Taiwan, it’s not just dry land where snakes are around every corner, but the ocean too. There’s several sea snake species, and the blue-lipped sea krait (Laticauda laticauda) is plentiful, particularly along the east coast.

This species reaches 150cm, and isn’t fully aquatic, straying to land to rest and digest food. Its hotspots include the coastal town of Chenggong, the tropical coasts of Kenting National Park, and Orchid island, where it coexists with its close relatives, the black-banded sea krait (Laticauda semifasciata) and banded sea krait (L. colubrina). Like the other sea kraits, its venom is highly neurotoxic, yet they’re so non-aggressive that they pose no threat to fishermen and scuba divers, unless picked up.

This species ranges from Fiji to Indonesia to Japan’s southerly Ryukyu islands. Though poorly researched, blue-lipped sea kraits produce a neurotoxin called laticotoxin a. Occasionally, they take shelter in the dens of birds on beaches. Likewise, blue-lipped sea kraits are proven prey of land predators such as the red-banded snake (Lycodon rufozonatus).

 

 

7	Formosa slug snake

The most common slug-eating snake found in Taiwan. The Formosa slug snake (Pareas formosensis) reaches a maximum of 70cm and is no threat to human beings. They’re both non-venomous and lack a jagged pair of front teeth which can lacerate your arm. Formosa slug snakes inhabit southeast China and Vietnam, but have the highest concentration of sightings in Taiwan by far. 

Pareas formosensis is most plentiful in high altitude forest areas, where they can be found coiled up on small leaves, dripping in the rainfall. Like other Pareas slug-eaters, they have an unbalanced jaw with more teeth on the right side, allowing them to grip a snail shell and suck the soft inside free using alternating jaw retractions. 

Rainfall is the secret ingredient for this snake. They hunt their slug prizes either during or after rainfall, when they come out in droves. They have a surprising tolerance for cool conditions, moving around freely in low temperatures whereas a slug snake in Thailand might hide away. The only threat from Paras formosensis is a vile smell they release when harassed.

 

 

8	Atayal slug snake

The second Pareas slug snake of our list, this was only confirmed as an independent species in 2015. For years, scientists had noticed individuals of Formosa slug snakes with inconsistencies, originally filed as simple morphs. But detailed genetic testing revealed a new species: Pareas atayal, named after a Taiwanese indigenous people. The two species often lived side by side, but had clear differences. Paras atayal had pale yellow eyes, instead of near red for Formosa slug snakes.

While the latter had completely smooth scales, the new Pareas atayal had moderately keeled (rough) scales to touch. Additionally, P. atayal had a longer snout, and even more unbalanced jaw, with 11 teeth on the left lower jaw and 20 on the right, versus 13 on the left and 18 on the right for Formosa slug snakes. The scientists discovered that Formosa slug snakes fed more heavily on slugs, while the new Pareas atayal gravitated towards snails, possibly because their longer snout made extracting them easier. Genetic testing revealed a close relationship, but easily enough separation to be full species.

Pareas atayal again lives in cool, rainy forests. This was the first discovery of an endemic Taiwan snake since 1931.

 

 

9	Taiwan stink snake

A non-venomous constrictor with a crushing grip. At up to 240cm, the Taiwan stink snake is the island’s longest snake. They’re thick too, one of the most heavily built of their Elaphe ratsnake family. Taiwan stink snakes (or king ratsnakes) inhabit all of Taiwan, plus a swathe of China. There’s a large colour variety, from basic olive-grey to bright yellow to pale cream or almost black. Scientists debated whether these were subspecies, before realising that Elaphe carinata naturally has many morphs.

Taiwan stink snakes are beloved by farmers for hoovering up rats in crop fields, but they also eat plenty of snakes: red-banded snakes, Chinese moccasins, kelung catsnakes, big-eyed ratsnakes and oriental ratsnakes.

Taiwan stink snakes were named for the especially vile smell they produce when manhandled. One of their talents is seeking out water culverts to slither through, and they’re commonly spotted crossing roads or on garden tiles. In captivity, they’re nervous and ready to strike at the slightest botherment.

Taiwan stink snakes swallow pretty much anything. In 2004, two males and one female were captured by a pond in northern Taiwan’s Taoyuan county. The stomach contents were as follows: one garden slug, one Stejneger’s grass lizard, two Formosan striped field mice, and one Tanaka’s gray shrew.

 

 

10	Taiwan coral snake

A lethal neurotoxic snake, but one that causes virtually no deaths, due to an extremely shy personality. This is a naturally rare snake, which is rarely encountered near human habitation. Taiwan coral snakes are endemic to Taiwan island, occurring nowhere else. They’re a shy species which lives on forest floors in mountainous regions, lurking in stone cracks and amid decaying plant matter, moving slowly and deliberately.

Long parallel stripes of juicy red and jet black are the ID sign for this species. If you know what to look for, they’re easily recognisable, as no Taiwan native quite resembles them. There’s also a white neck collar, and a very flat looking head. Taiwan coral snakes max out at 98cm and appear at elevations of 500-1500 metres.

The venom of this species is poorly researched. In fact, everything about them is poorly researched. But their mainland cousin, MacLelland’s coral snake, managed to kill the famous herpetologist Hans Schnurrenberger after 8 hours. Luckily, the earlier study covering 4647 Taiwanese snakebite victims mentioned zero bites from this species.