I.    The Six Common Venomous Snakes in Taiwan

1. Hundred Pacer (Deinagkistrodon acutus)

Features:

A venomous snake with a potent hemotoxin. This egg-laying mid-sized snake has a short, thick body, large triangular head, thin neck and upturned snout. The top of the head is brown in color while clear triangular patterns can be seen along the sides. The belly has black spots while the tail is a black-brown color.

Behavior:

Active during the day and night. Usually lives at the bottom level of deciduous forests with birds and rodents making up the majority of its diet. When disturbed, it raises its head while also making a warning hissing sound and constantly waggling its tail.

Distribution:

Found at medium to low altitudes in broad-leaf forests, bamboo groves and river valleys throughout Hualien, Taitung, Pingtung and Kaohsiung.
 

Bite Symptoms:

Within a few minutes of the bite, the surrounding flesh dies and turns black highlighting the puncture wounds. The wound is deep with widely spaced tooth marks and quickly becomes swollen. The skin and muscle turn black from necrosis, blisters form around the tooth marks and the wound begins bleeding. The victim feels a burning pain and the size of the necrotic region depends on the amount of snake venom injected and the depth of the bite.

Bite Treatment:

Hundred pacer anti-venom.

2. Pointed-scaled Pit Viper (Trimeresurus mucrosquamatus)

Features:

A medium-sized venomous snake with a potent hemotoxin. The back is a brown or tan-brown color, with three rows of irregular dark-tan colored round patches. 

Behavior:

Active at night. Inhabits abandoned houses and log piles. Feeds on birds, rodents, frogs and lizards. When disturbed, it raises its head and coils its body. The tail waggling restlessly is a sign that it is about to attack.

Distribution:

Found at low to medium altitudes in brushwood, bamboo groves, mountain gullies, river valleys and dry farmland throughout Taiwan.

Bite Symptoms:

Within a few minutes of the bite, the surrounding flesh dies and turns black highlighting the puncture wounds. The wound site quickly swells with the skin and muscle turning black due to necrosis. Blistering occurs and the wound bleeds continuously and feels as if it had been branded with hot irons. The size of the necrotic area depends on the amount of venom injected and the depth of the bite.

Bite Treatment:

Pit Viper or Green Tree Viper anti-venom.

3. Chinese Green Tree Viper (Trimeresurus stejnegeri stejnegeri)

Features:

A small venomous snake with a potent hemotoxin. It has a thin neck, large triangular head, green body and red eyes. There is a white or two red-white lines running along either side of the body. Due to its brick red colored tail, it's also known as the Red Tail.

Behavior:

Ovoviviparous, mainly active at night and is found coiled around branches in brushwood. Diet consists mainly of birds, rodents and frogs. When disturbed, it raises its head and coils its body. The tails waggling restlessly is a sign that it is about to attack.

Distribution:

Found at medium and low altitudes in brushwood, bamboo groves, mountain gullies, river valleys and dry farmland throughout Taiwan.

Bite Symptoms:

When bitten, black puncture marks can be seen. The surrounding area quickly becomes swollen, with the skin and muscle turning necrotic and blisters forming in the surroundings. The wound bleeds and feels as if on fire.

Bite Treatment:

Pit Viper or Green Tree Viper anti-venom.

4. Russell's Viper (Vipera russellii formosensis)

Features:

A medium-sized venomous snake with a toxin that is both hemorrhagic and neurotoxic. There are three rows of a chain pattern along the back made up of round patches that have a grayish-white border and brown or dark brown inside. The belly is white and covered with small black spots.

Behavior:

Ovoviviparous, feeds on rodents. It moves slowly with a lateral motion. When disturbed, it coils into a circle, makes a hissing sound and makes sudden strikes.

Distribution:

Found at medium and low altitudes in areas such as Hualien, Taitung, Kaohsiung, Pingtung and Nantou. Main habitats are mountains areas, dry farmland, river gravel and sugar cane fields. 

Bite Symptoms:

When bitten, black puncture marks can be seen. The surrounding area quickly becomes swollen, with the skin and muscle turning necrotic and blisters forming in the surroundings. The wound bleeds.

Bite Treatment:

Russell's Viper anti-venom.

5. Banded Krait (Bungarus multicinctus multicinctus)

Features:

A snake with the most deadly neurotoxin among terrestrial venomous snakes. It is relatively placid and rarely attacks human unless wounded or threatened. The head is an oval shape while the back has a very distinctive black and white banded pattern. 

Behavior:

Oviparous, often lives near water. Emerges at dusk and is nocturnal by preference. Feeds on other snake species, lizards, swamp eels and loaches. 

Distribution:

Found at low altitudes in Taiwan, Kinmen and Matzu near water, rivers and ponds.
Bite Symptoms:
The needle-like bite marks are hard to see. When bitten, it feels as if there are ants crawling over the wound. Victim becomes sensitive to wind, experiences blurriness of vision, numbness at the root of the tongue and difficulty breathing.

Bite Treatment:

Banded Krait or Common Cobra anti-venom.

6. Common Cobra (Naja naja atra)

Features:

A medium-to-large sized snake with neurotoxic venom. May be tan-brown, brown or dark brown in color. Those with a black belly tend to be larger in size and the head is usually oval in shape.

Behavior:

Oviparous, when roused, the neck spreads out so it is shaped like a spoon and makes a jet-like hissing sound. There are wide white patterns on the back with black spots inside that when expanded look as if the snake is wearing a pair of spectacles.

Distribution:

Found at low to medium altitudes in dry farmland, orchards and slopes with mixed brushwood throughout Taiwan. Mainly hunts during the day feeding on rodents and frogs.

Bite Symptoms:

The bite marks are small and shallow with a small amount of bleeding from the wound. The site quickly turns black and blisters.

Bite Treatment:

Banded Krait or Common Cobra anti-venom.

II.    Types of Snake Venom

1.    Snake Venoms
1) Hemotoxins: Most snakes in the Viperidae family have hemotoxic venom.
2) Neurotoxins: Most snakes in the Elapidae family have neurotoxic venom.
3) Myotoxins: Most snakes in the Hydrophiidae and Laticaudidae families have myotoxic venom.

2.    Types of Snake Venom
Snake venom is very complex with different active components. The various proteases can be antagonistic, synergistic or autonomous in their effects, resulting in even more complicated reactions. There are over 20 kinds of proteases that occur in snake venom. While not all snakes have so many, they usually have at least 6~12 types. Each type acts in its own particular way. Some perform a digestive function while others specialize in paralyzing the prey's motor functions. Some of the more well-known proteases are listed below:

1) Cholinesterase:
Mostly found in the venom of the Elapidae family. It attacks the nervous system causing the muscles to relax. It also blocks the prey's neuro-transmissions, resulting in death.

2) L-amino acid oxidase:
Found in the venom of some Viperidae family members, the venom is yellowish in color and is mainly used for digestion and to trigger other proteases.

3) Hyaluronidase:
Found in most venoms, it accelerates the effect of other toxins.

4) Proteinases:
Commonly found in the venom of the Viperidae, it helps the snake with digesting its prey. This protease is what causes the large areas of damaged tissues in bitten people.

5) Adenosine triphosphatase:
Found in most venoms and particularly those from the Viperidae. It is mainly used for paralyzing the prey so it can't move.

6) Phosphodieterase:
Appears in all snake venoms. It paralyzes the heart of the prey. The effects of other proteases have not yet been ascertained. What needs to be emphasized here is that even neurotoxic snake venoms contain not only neurotoxins but also other toxins. They are referred to as such because the venom mainly acts on the nervous system of the bitten prey.

III.    Snake Bite Prevention and Treatment

1.    Why Do People Get Bitten by Snakes?
Research shows that around 60% of people bitten by snakes were playing with the snake or trying to kill it. The other 40% were bitten by accident. Snakes don't actively attack their prey unless roused or striking back in self-defense after being trodden upon. Since snake venom is not easy to produce and humans aren't part of its regular diet, venomous snakes would rather not waste their venom on humans. As a result, there is usually some kind of warning before they bite. The Common Cobra for example raises its head and makes hissing noises while the Pointed-scaled Pit Viper coils up and makes a warning sound as well.

2.    How to Prevent Snake Bites
Prevention can be divided into home prevention and outdoor prevention.

a. Near the Home:

1.    Regularly clear weeds, trim bushes and sweep away fallen leaves to remove hiding places for   venomous snakes.

2.    Remove unnecessary timber and flowerpots so they don't provide venomous snakes with a hiding place.

3.    Trim away branches and vines near the windows so snakes don't use them to crawl inside the house.

4.    Fill or repair all holes and cracks in the walls or floors so venomous snakes can't get inside or hide in these places.

5.    Check all vents and cover them with cloth/wire mesh to keep snakes out of the house.

6.    Leftover food should be disposed of as soon as possible so it doesn't attract rodents, which in turn draw snakes into the house.

7.    If there is a rodent infestation in the house, get a pest control company as soon as possible to have them removed.

8.    If living in a rural area, the house should be sprayed regularly to prevent snake prey such as frogs, lizards and insects from getting inside the house.

9.    Keeping livestock such as chickens, ducks, pigeons or guinea pigs may also lure snakes inside the house.

10.   Regularly drain ponds and keep them clean because snakes may come to drink water or be drawn by the frogs and other animals in the pool.

b. Outdoor Prevention:

1.    Watch out for places frequented by venomous snakes. Keep an eye on where you are standing or sitting.

2.    Wear long leather or rubber boots.

3.    Wear loose pants made of dense fabric.

4.    Avoid entering long grass, brushwood or overgrown rocky areas.

5.    Avoid nighttime activities because this is when venomous snakes are most active. If unavoidable, use a flashlight or torch for illumination.

6.    Take special care when sleeping at night because venomous snakes of the Viperidae family are drawn by body heat.

7.    Avoid walking barefoot at night or without a flashlight.

8.    Do not stick your hands and feet into hollow logs, holes or caves because there might be venomous snakes hiding inside.

9.    When you encounter a venomous snake, stay calm and do not make any sudden movements.  In such an encounter, the venomous snake is more nervous than you are, so you should stay still or withdraw slowly. Once there is sufficient space, move away.

10.   Do not toy with venomous snakes as this will make them angry and increase the risk of being bitten.

11.   Do not toy with or touch dead snakes. If the venomous snake is not totally dead there's a high risk of being bitten.

12.   If a snake must be killed and bagged for identification purposes, wear anti-bite gloves or hook it into the bag with a long branch.

3. Treatment After a Snake Bite

9 Do's for Treating Snake Bites

1.    Do stay calm: Staying calm is the golden rule for surviving a snake bite. It takes time for the venom to act. If time is wasted through panic, survival becomes doubtful.

2.    Do try to suck or squeeze the venom out: The venom is a protein, so as long as there are no wounds in the mouth, it can be ingested safely. The venom should be sucked out as soon as possible.

3.    Do remove jewelry or watches: The snake bite wound will start swelling so personal accessories should be removed to prevent more injury.

4.    Do record the time of the bite: How quickly the wound swells is a good judge of venom quantity.

5.    Do place the limbs lower than the heart: This will slow the progress of the poison.

6.    Do seek medical attention as soon as possible: The only way to treat the venom is to get to a hospital as soon as possible and get an anti-venom shot.

7.    Do remove the fangs from the wound as soon as possible: For neurotoxic venomous snakes such as the Banded Krait and Common Cobra, their short fangs mean that the amount of venom is directly proportional to the bite time.

8.    Do remember the snake's features: If it was a venomous snake, this will allow the doctor to inject the right anti-venom and buy time for treatment.

9.    Do get a rabies shot.

4. Don'ts After a Snake Bite:

1.    Do not cut the bite open: Some victims of snake bites end up dying not due to the snake venom but because they cut themselves.

2.    Do not use an elastic bandage: If an elastic bandage is used to limit the spread of the venom, it will merely worsen the damage in that part of the body.

3.    Do not drink alcohol: Some Taiwanese people think that drinking alcohol will neutralize the venom. In fact, drinking alcohol only accelerates blood circulation and allows the venom to work faster.

4.    Do not apply an ice pack: Icing only worsens the damage. A lot of patients end up having to be amputated because of ice packing.

IV.    Venomous Snake Q&A

Q1. What Is the Most Venomous Snake in Taiwan?
The most venous snake in Taiwan is the sea snake. Sea snakes however are placid by nature and rarely bite people, so they aren't usually considered to be the most venomous. According to official records, the most venomous snakes in Taiwan are the Hundred Pacer and Banded Krait. The former is ranked so high because it has long fangs and large amounts of venom. When a person is bitten, the bite site swells up and bleeds, so it is classified as a hemotoxic venomous snake. Victims of the Banded Krait on the other hand initially don't feel any pain or itchiness and experience no swelling or bleeding. The victim thinks the bite was harmless and may seek medical attention too late. This type of neurotoxic venom disrupts neural transmissions, however, and its symptoms include sleepiness, blurriness of vision and breathing difficulties. When this happens, hospitalization is usually too late.

Q2. Can the Common Cobra in Taiwan Spit Venom?
Some people think that when the Common Cobra raises its head and expands its neck, the hissing sound is poisonous gas being released. In reality, the Common Cobra can't actually release poison gas but it can spit poison. The cobra is usually not higher than a man so its spit is not dangerous. If in a laboratory or when crouched down looking at the Common Cobra, however, care must be taken to make sure that you are not blinded by the spit venom. Spit venom does not harm other parts of the body.

Q3. Do Venomous Snakes Always Have a Triangular Head? Or Are All Snakes with a Triangular Head Venomous?
This is not necessarily the case. Common terrestrial venomous snakes in Taiwan such as the Hundred Pacer, Pointed-scale Pit Viper and Green Tree Viper all have the classic triangular head shape. But the Common Cobra and the Banded Krait don't. The False Viper in the Colubridae family is harmless but has a triangular head, so don't judge a snake by its appearance. The placid and harmless Green Snake for example is often killed because it is mistaken for the venomous Green Tree Viper.

Q4. If Chased by a Snake, Should I Run in an S-shaped Pattern so the Snake Can't Keep Up?
Venomous snakes' top crawling speed is around 12km/h. This is no match for humans with a running speed of 30km/h. If it really comes after you, don't worry – an animal that crawls on its stomach can't possibly beat a man running on two legs. Snakes won't actually chase after humans anyway. When it runs into you, it's already scared and all it wants to do is get away. If the human also panics, doesn't know what to do, or even ends up running in the same direction as the snake, he or she has a good chance of getting bitten. In such a situation, just don't move or back slowly away. The snake will then run away in an S-shaped pattern.

Q5. If You Get Bitten by a Hundred Pacer, Will You Die After Taking One Hundred Steps?
This is a good description of how powerful the Hundred Pacer's venom is. The Hundred Pacer is a hemotoxic venomous snake and once a person is bitten, the bite site will swell to two-times its normal size, bleed and become necrotic. If anti-venom is not injected in time, the mortality rate is indeed quite high. If treatment is provided within 1~2 hours, however, death is unlikely.

Q 6. Not Greedy Enough to Swallow an Elephant
The head of a snake is actually quite sturdy to stand up to the kicks of the prey being swallowed. For swallowing larger prey, its skeleton is linked by strong and very flexible joints. The jawbones in particular are only held together by tendons and muscle, so each side of the snake's lower jaw can move independently to allow it to swallow large prey. Snakes can usually swallow smaller prey in one bite. If the prey is too large to swallow right away, the snake usually starts with the head. Here the snake's fangs help to fix the prey in place, with one side holding it in place while the other side releases to allow the prey to be swallowed further. This cycle is repeated until the food is completely swallowed. The snake also secretes large amounts of saliva to act as a lubricant while swallowing. When larger prey passes through the throat, the end of the breathing tube sticks out from underneath. This acts like a snorkel to allow the snake to breathe while it swallows. Snakes generally take 3~5 minutes to swallow their food, though larger animals like kangaroos may take several hours. Despite such a sophisticated swallowing mechanism, there is no way that a snake could swallow an elephant.

Q7. Venomous Snakes Can't Poison Themselves or Each Other with Their Bite
Snake venom is secreted by glands and then stored in the venom sac. To be used, the venom is pumped from the venom sac into the fangs. The snake's venom sac has a structure similar to the human stomach. Though stomach acid is like concentrated hydrochloric acid, the stomach wall protects humans from injury, and the same setup works for venomous snakes as well. This means if venomous snakes bite each other or themselves, they will still die. Venomous snakes usually don't attack others of the same species, however. The fangs and venom are not usually used when they fight. King Cobras for example wrestle with each other until the weaker snake's head is forced to the ground. The loser then flees and is not actually bitten to death. If they really do fight with fangs and venom, both will end up dead and there is no winner. 

Q8. Won't the Kingsnake Be Poisoned by Eating the Rattlesnake?
Snakes eating snakes is quite common. The Banded Krait for example often feeds on the Green Tree Viper. The rattlesnake is a favorite food of the Kingsnake (Lampropeltis getula) and the Kingsnake is immune to rattlesnake poison so it is not at risk of being poisoned.

Q9. Can people be poisoned by eating venom or venomous snakes?
The answer is no. As long as there are no wounds in the mouth or stomach, you won't get poisoned by eating venom or venomous snakes. This is because the venom is made up of proteins and these are destroyed by the stomach acid. Venomous snakes, however, are infested with all kinds of parasites, and there are many cases of death due to threadworms penetrating the body. The eating of snake venom and venomous snakes should therefore be avoided.

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Text and images are provided by National Museum of Natural Science (The Digital Museum of Nature & Culture)