The illustrated Coconuts guide to Hong Kong’s venomous snakes

Words/Photos: Robert Ferguson

DISCLAIMER:  We cannot be responsible for readers’ inaccuracy in identifying snakes based on this guide. There are many variables that go into identifying a snake properly, and even experts can make mistakes. Do not use this guide to help you decide whether it is safe to touch or pick up a snake. Leave all snakes alone, and stay outside of striking or spitting distance (at least five metres).


Hong Kong has a recorded 52 species of snake. Six land species can inflict life endangering bites (the Banded Krait, the Many Banded Krait, Chinese Cobra, King Cobra, and Coral Snake), with their venom causing nerve-related necrosis and tissue damage. The six include the Red-Necked Keelback, which is a rear-fanged colubrid – meaning that in order to inject venom, it has to grasp its prey and literally “chew” in the venom using its rear fangs, unlike the others which can simply strike and release. The good news is that this makes it extremely rare for any serious bites to happen to humans.

The two other venomous snakes –  the Bamboo and Mountain Pit Viper (both pit vipers) – have bites that can cause extreme pain and swelling (and still pose a fatal threat to children and dogs).


The author with a python.

Six other snakes (opistholglyphous) have enlarged venom fangs at the back of the jaw, but are not known to produce much reaction in humans. The Common Rat Snake and the Burmese Python are not venomous, but do get very large, and their teeth can cause nasty cuts and gashes.

The other lethal snakes not listed above, as they are so uncommon, are the Tonkin and Pointed Scale Pit Vipers, and any sea snakes. (All sea snakes are venomous.)


A Bamboo Pit Viper

There is NO easy way to tell venomous from non-venomous snakes, and even if you know snakes well, identification is not always clear in the heat of the moment. (Can you really tell if that the third supralabial scale is NOT touching the eye and nasal scale? Thought not.)

So basic principles apply: leave them alone, and they will leave you alone. You will generally not be attacked by a snake. Why would it bother? it can’t eat you! In Hong Kong, all snakebites on humans are defensive.


A Chinese Cobra

Identifying a venomous snake

1. Is it (bright) green?

Often confused and mistaken for each other, it’s either the a) Venomous Pit Viper, or the harmless b) Greater Green.

a) The Bamboo Pit Viper (Trimeresurus albolabris)

  • Venomous, with an extremely painful bite. Responsible for 95 percent of all bites in Hong Kong (about 30-50 a year), but no recorded fatalities.
  • Very common.
  • Primarily nocturnal.
  • One of the few snakes that will not move away immediately.
  • Key differentiating features: Triangular-shaped head with many small scales, thin obvious neck, orange-yellow or red eyes, with slit (not round) pupil, reddish-brown streaked tail, and a deep nasal pit.


Bamboo Pit Viper

The Pit Vipers like to ambush their prey, so they do not normally move when they hear you, and rely on their camouflage to remain undisturbed; plus they can “see” and can strike at night using their heat sensing pit organs.

The Pit Vipers are nocturnal, so if you see a green snake during the day. it’s more than likely the harmless and inoffensive…

b) Greater Green Snake (Cyclophiops major)

  • Non-venomous.
  • Key differentiating features: Elongated head with large scales and no neck, Grey, golden or light brownish eyes with large black pupils, very likely to move rapidly away from any encounter.


Greater Green Snake

 2.  Does it have a red neck?

Then it’s the Red-Necked Keelback (Rhabdophis subminiatus helleri).


Red-Necked Keelback

  • Venomous and poisonous.
  • Not aggressive. Most human bites involve a light nip with the front teeth. However, bites inflicted with the rear fangs – though rare – can be lethal.
  • Often seen hunting frogs during the day.
  • Key differentiating features: Olive green with a red patch just behind the head, with yellow and black flecks throughout the body. Red marking can be quite faded in older adults.

Red-Necked Keelback

Juveniles are particularly beautiful. Adults can secrete a toxic white substance from a groove in their necks making the Red-Necked Keelbac unique as a venomous and poisonous snake.

3. Does it have black and white or black and yellow bands/stripes?

Many snakes in HK appear to have bands, but the only strongly banded venomous species are the deadly a) Kraits and the b) Coral Snake.

a) Many Banded Krait (Bungarus multicinctus)

  • Venomous and extremely toxic. The venom can lead to respiratory paralysis and heart failure. It will bite readily if picked up, and has a flexible neck that can twist and bite.
  • Key differentiating features:  It has black and white bands. Any large snake with black and white bands is a Many Banded Krait. If it is a small snake it can be confused with a Wolf Snake, but it it’s normally much larger, and it has no neck. It also has the unique ability to turn its head and bite you if you hold it behind the neck, which is how you would hold a normal snake (which you should only do if you really know what you’re doing!).

Many Banded Krait

There is also the Banded Krait (Bungarus fasciatus), which is rare due to loss of habitat. These large alternating-black-and-yellow banded snakes, whilst not aggressive, can also deliver fatal bites.

The Many Banded Krait with more than 30 bands can sometimes be confused with the harmless Wolf Snake (Lycodon aulicus), which has a lot fewer rings.


Wolf Snake

b) The Coral Snake (Calliophis macclellandi)

  • Highly venomous but rare and not aggressive.
  • Key differentiating features: Thin black stripes on a reddish brown body, with a white band behind the eyes on the head.

Coral Snake

4. Does it have a hood?

Then it is a cobra. Either a) the common Chinese Cobra, or b) the rare King Cobra.

a) Chinese Cobra (Naja atra)

  • Venomous and highly dangerous. Bites may cause tissue necrosis and death.
  • Active day and night.
  • Will usually try to escape, but if confronted will raise its forebody, spread its hood, hiss, and strike readily. Some snakes have been known to spit venom.
  • Key differentiating features: A heavy bodied snake, 90 to 130 centimetres long, mainly black, but sometimes/rarely grey or gold in colour. A short, wide hood, usually with white eye spots, or “spectacles”.

Chinese Cobra

b) King Cobra (Ophiophagus hannah)

  • Extremely dangerous; fatalities have been recorded in Hong Kong.
  • Mainly out during the day.
  • Key differentiating features: Can be black, grey, brown or even golden, with or without bands or spots. The rare King Cobra is banded (juveniles strongly so, with yellow bands on black), and unlike the Chinese cobra, it does not have eye-shaped markings on the hood.

King Cobra (Photo: Jean-Jacques Ferguson)

​Cobras are often confused with the Common Rat Snake (Ptyas mucosus) and the Indo-chinese Rat Snake (Ptyas korros).  Neither of these snakes have hoods, which is really the only easy well to tell them apart. The undersides of these snakes are slightly different, but you don’t see those much. The supralabial scales (the scales just along and under the eyes) have a black edge on the Common Rat snake, and that “band” behind the eye often helps with an ID.

The Cobra also has large occipital scales on top of its head.

The photo above shows the distinctive bars below the eye of the Common Rat Snake.


An Indochinese Ratsnake, often found in water, with a juvenile showing bands, and an adult (above) with an elongated body.

 

5. Is it mottled/spotted?

Does it have rows of alternating dark spots?  Then it is the Large Spotted Cat Snake (Boiga multomaculata).


Large Spotted Cat Snake

  • Mildly venomous, and not dangerous, but bites readily.
  • Arboreal (meaning it is often found in trees and bushes).
  • Key differentiating features: Very long and slender, with a distinct triangular head.

6. Is it in the water?

Not the only snakes you will see in the water – all snakes are good swimmers – but the snakes shown below rarely leave it, although they sometimes come onto land on rainy nights to hunt for frogs.

 


The Chinese Water Snake (Enhydris chinensis) is quite stout with an orange stripe on its lower flank. Only mildly venomous.


The Plumbeous Water Snake (Enhydris plumbea) is very small and only mildly venomous. 

7. What other venomous snake could it be?

It could be the Mock Viper (Psammodynastes pulverulentus).


Mock Viper

  • Mildly venomous with rear fangs, and no documented record of local bites.
  • Often out during the day.
  • They look aggressive, but also have a defence of playing dead very realistically, with their tongue out and body contorted. It can give you quite the fright if you pick one up thinking it’s a goner, so be careful!
  • Key differentiating features: On the small side, and comes in many different colours: dark brown, grey, red, orange, and almost white on occasion.

8.  Other venomous snakes not covered here:

 

  • Sea Snakes: highly venomous, but very rare.
  • ​Mangrove Water Snake: rare and only mildly venomous.
  • The Tonkin, the Point Scaled, and the Mountain Pit Vipers: highly venomous, rare, and no recorded bites.

9. There are many, many other non-venomous snakes:

For a comprehensive list with English, Chinese and latin names, please go to the Hong Kong Reptiles Flickr group (and feel free add your own images!).


Also, don’t be fooled by the clever snake-mimicking swallowtail caterpillar, which also shoots out a bright red forked “tongue” when alarmed.

10. Other dangerous snakes:

The Burmese Python (Python bivittatus), which is mainly nocturnal. It eats warm-blooded mammals up to the size of a large dog (!), but it is not venomous. Its potential danger comes from its size, and recorded attacks appear to be limited to small animals and pets.


Burmese Python

WHAT TO DO IF YOU ARE BITTEN

 

  • Move away from the snake, call emergency services and get to a hospital. Seek medical care without delay! Even a bite from a non-venomous snake may require a tetanus shot or booster.
  • Take note of the snake’s appearance. This is important, as treatment varies. Don’t try and catch or kill the snake, but take a picture if you can, or try and remember its shape and colour.
  • Be as still as possible. If you’re waiting for help to arrive, lie down on your back and take deep, steady breaths.
  • Clean the wound with water. Be gentle.
  • Remove clothing, jewellery, or constricting items.
  • Never apply a tourniquet. If you don’t know your snakes, it is better to immediately apply a pressure bandage/piece of cloth around the bite as well as above and below the bite, as recommended by the British Army. Elastic wraps that you use for ankle sprains work well. Wrap it snugly, but you should still be able to put a finger under the bandage. However, if the species is not fatal (Bamboo Viper for example, or any species with hemotoxic venom), the pressure bandage will result in much worse tissue damage. But, as a friend once said, “I’d rather be alive with a bad limb than dead!”
  • No food or drink – especially not alcohol.
  • No stimulants or pain medication.
  • Receive antivenom with caution. Experienced doctors use antivenom with great caution as it carries its own risks. (In remote area hospitals may not have anti-venom, and some physicians lack experience. For a realistic account of snakebite in rural China, read this.)
  • Don’t try to suck the venom out.
  • Don’t apply ice

What to do if a large python grabs your dog?

If a large python is wrapped around your dog, try and unpeel the snake from its tail, keeping it taut. You can also pinch the end of its sensitive tail hard. Remember, the python is a protected species, so if you hurt or kill it, you could face a fine, or worse.

IF YOU FIND A SNAKE NEAR YOUR HOUSE

If you have a snake near your house then it is a good idea to have it removed… for the sake of both of you. Options include calling the police (who will then contact a paid snake collector who will release it Kadoorie Farm). Sometimes this results in the snake being killed, however.

Otherwise, you can call Steve Loman, who can respond to any calls for snakes on Hong Kong Island, at (+852) 9260-0842, or Will Sargent (+852) 9470-8442, who is a police-approved snake catcher on Lantau Island. You can also write a post on the Hong Kong Snakes Facebook page.

OTHER RESOURCES

 

  • Check out the Hong Kong Snakes Facebook page where you can post images and ask questions.
  • HKU reptile database
  • The book to get: “Hong Kong Amphibians and Reptiles” (1998) by Karsen, S. J., Michael, W. N. Lau, A. Bogadek.

 


ABOUT THE AUTHOR

Combining a career in media, most recently at the The Economist, along with NGO work, Robert Ferguson spends the rest of his time with his family and friends exploring the subtropical forest, jungles, beaches, paths and plains of Hong Kong, hiking and (photographically) hunting, and finally, researching and studying to find the best of Hong Kong’s wildlife. Check out his website: www.robswildlife.info.

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