Red necked keelback (Rhabdophis subminiatus) is now classified as a deadly venomous snake.

Red Necked Keelback – Venomous – Dangerous

Red Necked Keelback Snake, venomous, Thailand and southeast Asia.
A beautiful snake, usually under 1 meter, not very aggressive. ©2009 ThailandSnakes.com.

(Page Updated: 6 September 2016)

Rhabdophis subminiatus (Red-Necked Keelback Snake)

Thai: (ngoo lay sab ko dang)

Length: Up to 130 cm (1.3 meters). Usually under 1 meter.

Range: Thailand and southeast Asia.

Notes: These snakes are commonly found near water, lakes, ponds, and in gardens. Recently a friend had one in his swimming pool in Krabi town, southern Thailand.

Active Time? Daylight hours. I’ve found them sleeping around 1 foot off the ground in bushes.

Food: Frogs, poisonous Bufo toads, and fish. I have not seen them eat anything but frogs and toads.

Defensive Behavior: Spread out the neck slightly to make themselves appear bigger. Not as dramatic as a cobra. Lift their head and neck off the ground 4-5 inches.

Some snakes of this species, and others in the genus Rhabdophis, have displayed a rather unique defensive behavior of exposing the back of their neck and secreting poison from their nuchal glands. This is not all that common.

One researcher, Kevin Messenger, claims that the R. subminiatus helleri he caught in Hong Kong actually sprayed a mist of the poison into the air from the back of the neck. Quite amazing, if true, right? Obviously more study is needed into the secret life of this fascinating snake. Other snakes in Rhabdophis genus with nuchal glands: R. nuchalis, R. tigrinus, R. nigrocinctus, and R. chrysargos (in Thailand).

Here is an image of the snake expressing poison from the nuchal glands.

Nuchal gland poison from Rhabdophis subminiatus helleri
The liquid on the neck near the top of the red shade is poison acquired at least in part, from eating poisonous Bufo toads.

Here is the description in a scientific journal about Kevin’s encounter.

Venom Toxicity: LD50 is 1.29 mg/kg for intravenous injection (source). That is about the same rating as the very deadly “Banded Krait (Bungarus fasciatus)”. It was previously thought these snakes were harmless. Some kept them as pets and were bitten. In one case the snake was left to bite for two entire minutes before removing it from a finger.

Serious complications resulted requiring hospitalization and intensive care. Click for article. These snakes are rear-fanged and need to bite and hold on, or, repeatedly bite to have any effect on humans. Once they do either – there is the possibility of severe problems including renal failure and death. Recently a small boy of 12 years old was bitten by one he was keeping as a pet in Phuket, Thailand and he is currently being treated (11/5/10). Be very careful not be be bitten by these snakes. There is NO ANTIVENIN available yet for these snakes in Thailand. Scroll down for information about antivenin manufactured in Japan that may have some positive effect.

Another study in Japan ranked the venom as having an LD50 of 1.25 mg/kg for intravenous injection. (Japan Snake Institute, Hon-machi, Yabuzuka, Nitta-gun, Gunma-ken, Japan) V.1- 1969- Volume(issue)

In Japan they make limited amounts of antivenin, but it is specifically for their in-country use.

One WHO (World Health Organization) publication about the management of venomous snake bites in Southeast Asia mentions the antivenin for Rhabdophis tigrinus in Japan as having some effect on the venom of R. subminiatus. I am not sure if this is strictly for R. subminiatus found in Japan, or not. Worth a try though if you can get them to send you some antivenin. Otherwise, there is no other option – there is no monovalent antivenin specifically for R. subminiatus.

Japan Snake Institute
Nihon Hebizoku Gakujutsu Kenkyujo
3318 Yunoiri Yabuzuka
Yabuzukahonmachi Nittagun Gunmaken 379-2301
Tel 0277 785193 Fax 0277 785520
[email protected]
www.sunfield.ne.jp/~snake-c/
Yamakagashi (Rhabdophis tigrinus) antivenom. Also effective against rednecked keelback (R. subminiatus venom)

Update: The 12 year old boy bitten by the Rhabdophis subminiatus was treated for 2 weeks of intensive care, and released. He was bitten multiple times, the 2nd bite lasting over 20 seconds.

Offspring: I had a juvenile red-necked keelback I’ve taken photos and videos of and released into the wild. I cannot find anything much about offspring. Recently (mid-June) I found a DOR juvenile very recently hatched, so like most snakes in Thailand the time around June is when they are hatching out. The coloration of the juvenile is quite different from adults as you can see in the photo and video below.

Rhabdophis subminiatus Juvenile
A hint of red on the neck in the juvenile. A pronounced black banding at the neck and grey on the head is evident in juveniles.

Notes: These snakes can inflict a deadly bite when they are allowed to bite for longer than a couple of seconds. I know personally of two instances where a child was bitten for well over 20 seconds, and a man was bitten for about a minute. Neither wanted to hurt the snake to remove it forcibly, and both spent over a week in intensive care, with the possibility of renal failure and death. Do not play with these snakes. If you have one, do not free-handle it. Treat it like you would a pit viper or a cobra. The LD50 on this snake for intravenous was stated to be 1.29 mg/kg. That is VERY venomous.

As a precaution, any snake in the Rhabdophis genus should be treated with extreme caution. In Thailand we also have the diurnal Rhabdophis nigrocinctus, and Rhabdophis chrysargos, both of which may be able to inflict a medically significant bite if given the opportunity.

Red-necked Keelback Scientific Classification

Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Order: Squamata
Suborder: Serpentes
Family: Colubridae
Genus: Rhabdophis
Species: Rhabdophis subminiatus

Video – Red-necked Keelback

Video – Red Neck Keelback Snake ( <- click) video

Video – R. subminiatus I Released Into the Wild

About Vern Lovic

Snake posts by Vern Lovic. Amateur herpetologist roaming about Thailand on field herping tours and events to find king cobras, kraits, vipers, corals, keelbacks, and other snakes native to Thailand. FYI - Thailand has over 200 snake species. Here's our latest book with detailed information on Thailand's 35 Deadly Snakes. "Is That Snake In Your House Dangerous? Identify Deadly Thailand Snakes In Under 5 Minutes!" INFO HERE.

26 thoughts on “Red Necked Keelback – Venomous – Dangerous”

  1. had one in the garden, not too large, about 90 cm. Very docile. I directed it away with a stick, it slowly slipped away. Fast through the grass. Nice colors.

    1. Yes, exceptionally beautiful snakes… especially if they’re scared and show you the colors and flare up – wow. They don’t bother people at all – but so many people kill them – I see Thais do it all the time… sad to see it. But the good news is – there are PLENTY of them – they seem to be everywhere.

  2. Found one this morning under the doormat outside my house, in Khao Lak. I have a kitten that likes to run around in the garden so it worries me a bit to know this snake is around and i’ve seen it a couple times in the garden before. Do you think cats can scare them away or they will just attack if the cat tries to play with it.

    1. They’ll definitely avoid cats – kittens, whatever is bigger than them and that messes with them. These snakes wouldn’t bite much, they’d prefer to flee. That said, a good bite could kill your cat rather easily I’d think.

      1. I was in Khao Lak in 2012 and saw one of these in the grounds of the place we were staying, about an hour after dark, under lights on a footpath. A cat which we’d seen several times around the place was showing a great deal of interest in it. While I went off to get the camera my wife stayed and watched it. The snake struck at the cat and bit it on the lip; the cat immediately started to drool and then ran off. Didn’t seem like the snake got a good grip on the cat so hopefully it didn’t get a chance to work in a lot of venom, but we didn’t see the cat again – we left the next day. Didn’t know what kind of snake it was at the time (I’m from New Zealand, where there are no snakes) and was rather surprised to learn later that they’re so venomous. Pretty little things all the same.

        Thanks for this site, it’s really informative!

        1. Yep, those are super-hot snakes. The power of the venom is comparable with a monocled cobra or a krait. Wicked strong. Thing is, they have a rather inefficient venom delivery system with small fangs in the rear of their small mouth. Only people (and animals) that get bit for a lengthy time seem to be envenomated and have problems.

          The venom attacks the kidneys.

          Scary snakes because yeah, they are so beautiful and usually quite calm and non-bitey. Cheers man!

  3. i see many snakes of redneck which was commonly found in our place but its size was much more almost more than 3 mtrs i saw … so fast n active , beautiful , but very shy, here some body says its very venomous some are say no venom , many of localite are use to demo by keeping in there in bags an all… but never heard any bitten incident by this snake… plz tell me how venomous is this snake…

    1. Hi Rajesh,

      You don’t say where you are in the world. India? Pakistan? There is no Rhabdobphis subminiatus (red-necked keelback) that is 3 meters long. They don’t exist. Some other snake then. Not sure which snake you mean. Take a photo or find one on google image search. Cheers, Vern

  4. Just back from a trip down in Chumphon. We have a Durian farm and I have seen these guys often. The one one thing is they can move very fast and so I guess you
    have to be carful with them. The other day when out walking I came across a King
    cobra about to take on a swollen poison toad. But I have to say he did frighten me
    as he was over 2 meters and did not seem to happy to be disturbed.

    1. Yes, the red-necked keelbacks are fast, but always to get away. They don’t hang around to strike. Only if you pick one up or step on one, might it bite you. The king cobra eating a toad was most likely the Ptyas carinatus or Ptyas mucosus – both big rat snakes that resembled the king cobra. Unless you’re positive. That would be a new one on me though, kings are almost exclusively snake eaters. They do take monitors too – bigger ones.

      Cheers, and thanks for the comment.

  5. hi vern, wow you have great web site here. there are red necked keelbacked snakes all around Chiang Khan, Loei. also many more or less harmless speckled gliding tree snakes here as well. unfortunately snakes are killed here almost on site. If need be I bag em up and take them to forest if i can get them to cooperate. see quite a few species around these parts, vipers, cobras sometimes, many rear fanged snakes as well. really great work vern, gary

  6. I just used your website to identify a red necked keel back found in the garden here in Krabi.
    Thank you for your fantastic useful site. Have bookmarked for future reference.
    Thanks.

  7. Just seen a Red Neck Keelback snake around Pai, trying to hide in some long grass tried to scare it away, but it seemed very friendly and wouldn’t go away, it eventualy disappeared into the undergrowth very beautiful snake though.

  8. This little snake, the size of my index finger, bit my cat (somewhere in the mouth area) who was trying to tease it. The cat ran and so did the snake, very fast in the grass and hard to spot. My cat immediately foamed at the mouth which lasted for about 15 minutes. it then suffered spasm on its legs and it tumbled forward when it she was trying to walk. She’s two years old and weighs 4 kgs. I called my local vet and she ordered an injection at the nearby pet clinic. I administered the shot subcutaneously. The cat was fine after that.

    We are in the mountainous area of Kampot.

    1. That’s really interesting – thanks for the story. I have no idea what happened there. The snake is rear-fanged, is not built for envenoming, it needs to bite for either a prolonged time, or repeatedly to work venom into a bite. However, a bite by this snake on the mouth, introduces another variable… this snake has poison glands – Nuchal gland(s) on the top of the neck, and it’s possible your cat got some of the poison in its mouth I guess. No idea what the shot contained – if you can let me know, that would be great. Cheers!

  9. Hi..
    I am from north eastern part of India and I must tell you that the red neck killer back snakes are available in my village . I don’t know about other parts of the state or country but in August September months it is seen the most.Even it entered into my room two months back. I searched and found that the snake was the red neck killer back snake.

  10. This red neck killer back snakes;
    1)can escape very fast
    2) can climb in straight hills easily
    3) can shrink its body to pass through a very small hole.
    4) can’t tolerate the smell of kerosene.

    1. I disagree for #2. Never saw one climb anything with speed, certainly not a vertical hill if that’s what you’re saying.
      #4 – can anything tolerate kerosene?

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