Snake season has arrived in Hong Kong, so here’s a brief introduction to some of the main venomous land snakes you might stumble across (not literally, I hope!) whilst out hiking, trail walking or visiting a country park, and what to do if you’re unlucky enough to be bitten by one (also published as a static page here). But first, a quick lesson in terminology!
Poisonous vs Venomous
These two terms are often confused and used interchangeably, but simply put, poisons are secreted (so bad to touch or eat), whilst venoms are mechanically delivered (so via fangs, stingers or spines, etc.). Both poisons and venoms are toxins, which is the umbrella term for all harmful (organic) substances. The difference is in the delivery: poisons are passively ‘delivered’ for defensive purposes; venoms are actively delivered primarily for offensive (but also defensive) purposes.
‘Toxic’ snakes are thus largely venomous, although there are a handful that are also poisonous like the Red-necked Keelback, which has both a venomous rear bite (rarely utilised) as well as poisonous neck secretions acquired through its scrumptious diet of poisonous toads (clearly not poisonous enough in this instance, lol). Cute, non-aggressive snake, though, so have no fear! Especially since the Red-necked Keelback can often be found hanging out on local trails during the day.
Hong Kong’s Venomous Snakes
Here’s a table from Hong Kong’s Agriculture, Fisheries and Conservation Department (AFCD) showing our most common venomous land snakes. I cropped out the rarer venomous species and non-lethal ones. For the complete listing, with active links to further details on each snake species, see the original table here. See also the external links at the bottom of this page for more comprehensive information and guides on Hong Kong snakes, both venomous and non.
In summary, however, the kraits and cobras are the ones to be the most wary of, as they pack the most lethal bites. The Coral Snake is also lethal but fairly secretive, whilst the Red-necked Keelback is pretty docile and only bad if it gets with you with its rear fangs, which is rare. The Bamboo Pit Viper (pictured at top) is both aggressive and venomous (bad combo!), accounting for most snake bites in Hong Kong, but fortunately it’s not very lethal. Phew!
Also worth noting, of the snakes below, all are strictly or nearly always nocturnal, except for the cobras and Red-necked Keelback. So, if you stick to daytime hikes and walks, it’s only cobras that you really need to watch out for. I say “only cobras” like it’s no big deal, lol, but you catch my drift. Problem is cobras can be easily confused with non-venomous rat snakes, which are also diurnal, so when in doubt, err on the side of caution! Don’t forget, cobras look just like regular snakes when their hoods are down…
If you are unlucky enough to be bitten by a snake, it’s helpful if you can identify the species, so that both you and the hospital staff know how to manage the bite and with which antivenom to treat it, etc. Don’t attempt to catch or kill the snake. Taking its photo or making a mental note of its appearance is good enough. Sometimes you may not see what bit you, however, and in such cases it’s a good idea to examine the bite mark.
A bite that looks like two fang punctures is likely due to a venomous snake, whereas a bite that resembles two nested rows of superficial punctures is typically the result of a non-venomous snake. Unfortunately, not all bites may be so well defined and easy to classify, and if that’s the case, it’s safer to be pessimistic and assume the worst, lol. Then there’s the issue of envenomation (injection of venom). A venomous snake may sometimes deliver a painful but otherwise non-threatening ‘dry’ bite to conserve its venom, but I don’t suppose that’s something you really want to guess either!
So again, always err on the side of caution when it comes to snakes and snake bites, but where you know for sure what bit you, observe the following:
- Best case scenario: If bitten by a non-venomous snake, there’s no need to apply a pressure bandage to the area. You may wish to seek medical treatment, however, to get it cleaned up and see whether a tetanus shot is required, etc.
- ‘Mid’-case scenario: If bitten by a venomous snake that’s haemotoxic like the Bamboo Pit Viper (or any other viper or pit viper) or Red-necked Keelback, also don’t apply a pressure bandage to the area, as this can encourage tissue necrosis, which you definitely don’t want. Instead, get to the nearest hospital stat for treatment and observation.
- Worst case scenario: If bitten by a venomous snake that’s neurotoxic like any of the other venomous land species listed above (kraits, cobras et al.), call emergency services immediately and request urgent medical attention, then apply a pressure bandage (or whatever else that can serve the same purpose) as shown below. Try to keep the affected limb below heart level and remain immobile until help arrives.
Bottom line: You don’t want haemotoxins to remain concentrated in an area, but you do want to keep neurotoxins from spreading throughout the lymphatic system. Hence why it’s helpful to know what bit you. When in doubt or completely clueless, follow the worst case scenario and opt to apply a pressure bandage – which, to be clear, is not the same as a tourniquet (the objective of pressure bandaging is to restrict lymphatic flow, not blood flow).
Good video clip demonstrating pressure bandaging/immobilisation
Other dos and don’ts include remaining calm to avoid increasing your blood flow, keeping the affected limb below heart level, removing any restrictive clothing and jewellery from the affected limb (cut away clothing to minimise movement in the case of neurotoxic bites), and avoiding the consumption of food, drinks (especially alcohol), and any medication (e.g., pain relievers, stimulants) without first being given the green light by a medic.
Do NOT incise or attempt to cut out the bite, do NOT try to suck out the venom, and do NOT apply a tourniquet. These are outdated techniques that are no longer deemed medically sound, and which may in fact worsen the situation.
Signs & Symptoms
Below are some of the possible signs and symptoms to look out for following a venomous snake bite. Haemotoxic bites are usually more painful and slower to take effect, affecting the blood and surrounding tissues. Neurotoxic bites are typically less painful but much faster acting, affecting the nervous system to cause possible dizziness, blurred vision and/or muscle weakness/paralysis, etc. Symptoms and their severity are also impacted by the potency and quantity of the venom, and will vary from person to person.
- Antivenom – antibody-based medication used to treat certain venomous bites and stings; also known as antivenin or venom antiserum
- Colubridae (sing. colubrid) – family of rear-fanged snakes that includes Red-necked Keelbacks
- Diurnal – active mainly during the day like many cobras and Red-necked Keelbacks (also nocturnal, I should point out)
- Elapidae (sing. elapid) – family of neurotoxic venomous snakes characterised by hollow fixed fangs, amongst other things, that includes kraits, cobras, coral snakes, adders, mambas, taipans and sea snakes
- Envenomation – process by which venom is injected into a subject via the bite or sting of a venomous creature
- Haemotoxin – toxin that ruptures/destroys red blood cells (hemolysis), disrupts blood clotting and/or causes tissue damage and organ degeneration; also spelt or known as hemotoxin or hematotoxin
- Necrosis – death of most or all of the cells in an organ or tissue due to disease, injury or failure of the blood supply (e.g., haemotoxin-induced hemolysis)
- Neurotoxin – toxin that destroys nerve tissue causing neurotoxicity
- Nocturnal – active mainly during the night like kraits, Coral Snakes and Bamboo Pit Vipers
- Poison – in nature, a toxin that is secreted and passively ‘delivered’ through touch/absorption or consumption for defensive purposes
- Pressure bandaging – compression technique designed to restrict lymphatic flow (but not blood flow) and thus minimise the dissemination of neurotoxins and the risk of neurotoxicity; involves a moderately tight bandage wound up the affected limb, from below and over the snake bite towards the body; also referred to as pressure immobilisation, especially when a splint is also applied
- Tourniquet – compression technique designed to restrict blood flow; no longer recommended for the treatment of venomous snake bites
- Toxin – in nature, an organic substance harmful to organisms
- Venom – toxin that is actively delivered by mechanical means, such as fangs, stingers or spines, etc., primarily for offensive (but also defensive) purposes
- Viperidae (sing. viperid, viper) – family of haemotoxic venomous snakes characterised by hollow hinged fangs, amongst other things, that includes vipers, pit vipers, rattlesnakes and copperheads
Just for fun, lol.
For further information, see also:
- HKU: Reptiles of Hong Kong: Snakes (also lizards and turtles)
- AFCD: Venomous Land Snakes in Hong Kong
- Coconuts: Illustrated Guide to Hong Kong’s Venomous Snakes
- Southside: The Most Common Snakes in Hong Kong
- SCMP: Snake species creeping up in Hong Kong
- KFBG: What to do if you encounter a wild snake?
- St John (Australia) First Aid Fact Sheet: Snake Bite