What You Need to Know About Taiwan’s Snakes

Snake bites are fairly rare, only a few common species are venomous, and antidotes are widely available.

When you see a snake while hiking along a country trail, it would be useful to know the difference between a harmless greater green and the similar-looking but venomous green tree viper.

If you live near open farmland or dense woods, it would be similarly useful to know how to reduce the risk of a snake entering your home.

But most crucially, if you ever get bitten by a pit viper, cobra, or the hundred pacer, it would be really useful to know what, if anything, to do about it.

“Don’t panic,” say most medical authorities, such as Taiwan’s Centers for Disease Control (CDC). Its website recommends: “When bitten by a snake, please try to remain calm…and seek medical attention at a hospital as soon as possible.”

Go ahead and panic, says William Christopher Murphy, co-author of the Snakes of Taiwan website. “You might as well panic, because believe me, you’re going to anyway. Next, once you’ve calmed down a bit, take off any jewelry from around the bite site.”

Why? Because gold and silver react chemically with venom? To bribe someone to take your comatose body to a hospital? To send to next of kin?

“Because your finger or hand or leg or head is possibly going to swell up like a balloon, and you don’t really want it to be constricted by a ring or bracelet or watch,” explains Murphy. “After that, yes, apply a light bandage over the bite site, tie a stick to the affected limb to restrict movement, and most of all, get to a hospital or clinic.”

“Unless you’re in the high mountains, nowhere in Taiwan is more than an hour from a stock of anti-venoms, so you’re most unlikely to die,” continues Murphy, an American teacher of English who does most of his “herping” on Hutoushan in Taoyuan, as well as at Baling on the Northern Cross-Island Highway. Despite his decade of hikes into snake-infested hills, Murphy has never been bitten.

Bill Murphy certainly knows a harmless greater green from a green tree viper. Photo: Mark Caltonhill

“And Taiwan’s research, production, and storage of snake anti-venoms is among the best in the world,” concurs Murphy’s co-author, Hans Breuer, who favors Yangmingshan National Park, as well as a cave near Beitou where snakes snatch bats out of the air. Breuer has also collected and published his anecdotes in A Cobra Hijacked My Camera Bag: Snakes and Stories from Taiwan, and offers lectures on snakes in schools, for which purpose he keeps a pet rat snake (Ptyas korros; 細紋南蛇) in a vivarium in his study.

“Actually, children are generally the last ones who need educating about snakes,” he says. “Typically when I find a snake, if there’s a family nearby, the mother will scream, the father will want to kill it, the teenage son will go ‘So what!’, but the little daughter will say ‘How cute’ and then start asking questions about where it lives and what it eats and so on.”

Some academic research supports Breuer’s theory, suggesting that children under the age of four are not instinctively afraid of snakes, which suggests that fear of them is culturally learned rather than inherent.

His talks, which last about 90 minutes, “include general information about local snakes, their biology, lifestyles, and their importance for man and the environment – such as their role in pest control (both venomous and non-venomous snakes consume between 30 and 400 percent of their body mass each week in mice and rats) – and, well, simply their beauty.”

Hands-on experience

“The rat snake is a good species for petting,” Breuer says. “Although it is rather nervous initially after being captured and may bite or thrash about violently in an attempt to escape, it quickly settles down and after a few days may be handled with little danger of biting.”

Although Murphy and Breuer readily acknowledge they are amateur enthusiasts, their snakesoftaiwan.com website is an invaluable resource for anyone with even a passing interest in the island’s herpetology but who lack Chinese-language skills.

Snakes of Taiwan Website

The site is hands-on, presenting Taiwan’s 50 or more species not taxonomically or alphabetically, but rather by color, size, and patterning – that is, according to the features a casual observer might prioritize.

Click on a photo, however, and a world of detail opens up, describing everything from scientific name, distribution, habitat, appearance (down to the all-important number of rows of scales and whether the anal scale is entire or divided), ecology, and diet – but starting, in lower or upper case, with the fact a layman most wants to know: non-venomous, VENOMOUS, or HIGHLY VENOMOUS.

It is to this last category that another good English-language webpage, Exhibition of Venomous Snakes in Taiwan, supported by the National Museum of Natural History (NMNH), is devoted. The site provides information on the toxicity of their venom, the degree of aggressiveness of their behavior, and their relative abundance.

Taiwan has six common members of the highly venomous category, and the site introduces them clearly and concisely, albeit somewhat morbidly focused on the nature of the bite and toxicity of the venom. For those interested in such things, however, there is also a detailed explanation of how different proteases in snake venom act – from those that attack the nervous system, blocking neuro-transmissions and causing muscles to relax (cholinesterases), and those that start to digest the victim’s flesh (proteinases), to those that paralyze victims (adenosine triphosphatase) or merely enhance the action of other toxins (hyaluronidases).

The website also contains a useful FAQ section that challenges some of the myths surrounding snakes (see the “myths” sidebar). The answer to “Can people be poisoned by eating venom or venomous snakes?”, for example, is more complex than might be imagined. The basic answer is “No, venom is simply made up of proteins, which are destroyed by stomach acid,” so “as long as there are no wounds in the mouth or stomach, you cannot get poisoned by eating venom or venomous snakes.”

More of a danger, it argues, are snake parasites, cautioning that due to the “many cases of death due to threadworms…the eating of snake venom and venomous snakes should therefore be avoided.” Maybe someone should tell the vendors of Taipei’s Snake Alley night market, or at least their customers.

The NMNH also has useful suggestions on how to keep snakes out of your home, such as regularly clearing weeds and bushes, and sweeping up leaves to remove hiding places, trimming branches and vines near windows to prevent access, checking walls and doors for cracks and holes, and covering vents with mesh. Most importantly, however, keeping the house clean of leftover food because crumbs attract rodents, rodents attract snakes, and rat-eating snakes attract snake-eating snakes, the so-called king snakes. Do you still want your daughter to keep that guinea pig?

Despite the well-known cleanliness of Taiwanese homes, emergency services are regularly called out to remove venomous snakes. “Between 1,200 and 1,700 snakes are captured this way each year in Taipei City alone,” says Chen Szu-lung, curator of the Taipei Zoo’s Conservation and Research Center. “Islandwide, that number must be more than ten thousand,” he calculates.

Chen Szu-lung of Taipei Zoo discusses the habu’s distinguishing features. Photo: Mark Caltonhill

Most of these snakes are taken to more remote areas (Chen won’t specify exactly where) and then released. The center keeps a few snakes for research or educational purposes, and others are sent to academic and medical institutes for the “milking” of venom and production of anti-venom. To make anti-venom, horses and goats are injected with trace amounts of venom, and antibodies are then harvested from their blood.

This process was fairly haphazard until a decade ago, and captured snakes had a lifespan of just a few months. This put the CDC in the awkward position of being involved in the deaths of protected species (a category in which all but one of Taiwan’s venomous snakes belong), until the CDC joined forces with academic institutes to improve its ability to keep snakes alive in captivity.

Chen’s research center also provides a home for non-native species intercepted during Taiwan’s customs checks (such as boa constrictors native to South America) and for pets no longer deemed owner-friendly, like an Egyptian cobra that bit and killed its owner.

The center is not open to the public, but Taipei Zoo also has an Amphibian and Reptile House that is. Besides housing a wide range of both local and foreign specimens, the Zoo facility also has good educational displays about the biology, ecology, and sexuality of various snake species, though this is only in Chinese.

Evolutionary outcomes

Much snake biology derives from the process of evolution, probably from burrowing lizards, a process that started about 150 million years ago. First they lost their front legs, followed by the hind ones, though in a few species these have evolved into cloacal spurs used to grasp during mating. These species include the Burmese python (Python bivittatus; 缅甸蟒), whose range includes the Kinmen archipelago. Measuring up to 6-7 meters in length, Burmese pythons often appear in news reports when firefighters around Taiwan are called to collect particularly large specimens, which are presumably escaped or abandoned pets.

In warm climates, snakes often lay eggs. In other – ovoviviparous – species, the eggs hatch inside the mother’s body and the hatchlings emerge as functioning free-living young. These include Taiwan’s green tree viper (Viridovipera stejnegeri; 赤尾青竹絲) and Russell’s viper (Daboia Russelli; 鎖蛇).

This female habu will stay with her eggs until they hatch. Photo: Mark Caltonhill

Also lost were snakes’ external ears, probably because getting soil in them while burrowing was annoying, though this does not mean snakes are entirely without hearing. In addition to vision, snakes also use smell to hunt prey, their forked tongues darting in and out to collect airborne particles that are then analyzed in the Jacobson’s organ in the roof of their mouths. Furthermore, many snakes, including pit vipers like the Taiwan habu, also have infrared-sensitive receptors in pits or grooves on their snouts that enable them to see the radiated heat of warm-blooded prey.

Snake jaws are strong enough to withstand the kicks of prey being swallowed, but are flexible enough to move independently and thus consume prey larger than the apparent mouth size.

The Taiwan slug snake (Pareas formosensis; 台灣鈍頭蛇) has more teeth on its right jaws than on the left, which helps it eat round corners inside a spiral snail shell.

Snake tails are quite short, as are their necks; everything in between is elongated thorax. Paired organs are arranged one in front of the other to maximize slenderness, and most snakes have only one functional lung. The green tree viper, also known as the bamboo viper, has a red-brown tail that it can wiggle to imitate worms or caterpillars, a process known as caudal luring, which attracts small mammals, lizards, and even unsuspecting birds.

This colored tail, as well as a white or white-and-red stripe down the length of its body, plus its triangular head, are the main ways to differentiate it from the harmless greater green. Also, it is nocturnal, whereas the greater green is active in the daytime and sleeps in trees after dark.

Although it is not aggressive, the green tree viper or GTV as Breuer calls it, is responsible for most snake bites in Taiwan as it rests in ground plants and bamboo litter during the day, and so is a menace for farmers. Nevertheless, deaths are rare as even the smallest clinic in the countryside stocks this specific anti-venom.

In fact, deaths from snake bites are generally quite rare in Taiwan. A 1964 article in the government’s Free China Review reported that fatalities, which had numbered around 50 in 1945, had “by 1963 been reduced to two…both snake hunters who were bitten while pursuing venomous species.” These men were probably not collecting snakes for consumption in Snake Alley, but killing them for cash. Snakes were considered a pest, and Yangmingshan National Park, for example, paid NT$5 per corpse in the early 1960s.

Since then, despite many snake species being protected, fatalities have fallen further. According to a study in the Journal of Acute Medicine in 2015, a total of 4,647 snakebites were reported in Taiwan between 2005 and 2009, but there were only two documented deaths. Most bites were by GTVs, habus, cobras, and krait, in that order, and fewer than 1% were by the dreaded hundred pacer.

So, as Murphy says, “The most dangerous part of my herping trips is probably the five-minute scooter ride home afterwards.”

Taiwanese Myths Surrounding Snakes and Snake Bites

1.     You should try to suck out the venom.

        No, that can be dangerous.

2.     If bitten by a hundred pacer, you will die within 100 paces.

        How the hundred pacer (Deinagkistrodon acutus; 百步蛇) acquired its reputation isn’t clear as it is neither Taiwan’s most venomous snake – that accolade goes to various sea snakes or the many-banded krait (Bungarus multicinctus; 雨傘節) on land – nor is it responsible for a high proportion of bites or deaths. That being said, a bite from the hundred pacer is painful and conspicuous, as the site swells up and bleeds, characteristics of hemotoxic venoms.

3.     Drinking alcohol helps neutralize snake venom.

        No. In fact, drinking alcohol accelerates blood circulation, which enables  venom to work faster.

4.     All venomous snakes have triangular heads and distinct stripes.

        Exceptions include the Chinese cobra and many-banded krait, whose heads are not triangular, and the red-banded snake (Dinodon rufozonatum; 紅斑蛇), which is striped but is not venomous, and the false viper (Macropisthodon rudis; 擬龜殼花), which mimics the Taiwan habu, also known as the brown-spotted pit viper (Protobothrops mucrosquamatus; 龜殼花), in having both a triangular head and stripes but is by-and-large harmless.

5.     If you encounter a snake, run away in a zigzag pattern.

        No, you should move away slowly in a straight line. Venomous snakes are not particularly fast, and with only one functional lung, cannot move quickly for long. In any case, snakes don’t chase humans; if one runs into you, it just wants to get away.

6.     Many of Taiwan’s venomous snakes were released by Japanese out of spite when they had to hand over the island to ROC rule in 1945.

        Although widely repeated, there is no evidence for this; early postwar initiatives by the incoming KMT-led government sought to continue the Japanese colonial administration’s attempts to eliminate all venomous snakes throughout Taiwan.

What to Do If Bitten by a Snake

  1. Stay calm. Increased activity, especially of the affected limb, may cause the venom to spread more quickly.
  2. Call for emergency help if available. Take a taxi or walk calmly to a hospital or clinic.
  3. Wash the bite with soap and water.
  4. Keep the bitten area lower than the heart.
  5. Cover the area with a clean, cool compress or a moist dressing to ease swelling and discomfort. Do NOT apply a tourniquet.
  6. Monitor your breathing and heart rate.
  7. Remove all rings, watches, and constrictive clothing, in case of swelling.
  8. Draw a circle around the affected area and note the time of the bite.
  9. Try to remember the snake’s size and appearance – even take a photograph if possible, though not if there is any chance of being bitten a second time. Second bites are often more venomous than initial ones, which may be warning “dry” bites.
  10. Do NOT try to extract the venom using knife incisions or by sucking.