Red Necked Keelback – Venomous – Dangerous

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

(Page Updated: 1 May 2022)

Rhabdophis subminiatus (Red-Necked Keelback Snake)

Thai: (ngoo lay sab ko dang)

Length: Up to 100 cm (1 meters). I’ve never seen one close to 1 meter in length.

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 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 unless very provoked.

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 (link changed).

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
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

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  1. Sadly, I killed one yesterday. My kitten was playing with it and I thought better of that. I had no idea I was in any danger however. Very pretty and lightning fast. I feel a bit bad about it. I suppose I should say thank you for identifying the snake for me and accept my regrets on killing it.

    1. That one isn’t likely to kill anybody or any cat, but if it got a good bite and held on, it’s possible.

  2. Saw loads approx 8 by the monkey swimming hole in Khoa sok Thailand this morning…we have been swimming in the river all week with our kids 2 & 8yrs old…only seen them today though…we are thinking the heavy rain last night might have flushed them out!

  3. Hi Vern, here is my redneck story. A few months ago, we went out the back side of the house, (Pattaya) and the wife screamed, A snake bit our cat! So I told her to take care of the cat, that was foaming at the mouth, and I would find the snake. Lifted up a stone slab, and there it was, coiled up, but the biggest surprise was a huge cane toad, sitting next to the redneck. I knew the snake was a redneck, since they are almost the easiest snake to reconize, But I didnt know if it was venomous or not. I didtnt have my snake catcher near by, so decided to kill it, then put the toad in a plastic bag, and dumped it in the neighbors yard!! hehe. So, was my cat poisoned by the redneck or the toad? Was the redneck going to try and eat the toad, and decided it was too big, or what? Is the poison of the toad, the same as the redneck, that he excretes from his neck? Why would they be sleeping together? I hope you can supply some answers, this seems to be a weird situation, and internet doesnt help, every web site has different facts, and most get poison and venom mixed up. Fortunately the cat survived. Also if im ever in a quiz program, and asked how many poisonous snakes there are, I can now say, only one!! Unless another is found!
    Thanks for you help! I will be trying to find some answers to these questions for a long time.

    1. Hahaha! Interesting… I’d guess the cat was toad-licking. I don’t know what the poison consists of on the redneck keelback’s neck… but it likely closely resembles that of the toad. At least that’s what I’ve read. A rednecked keelback bite to the cat wouldn’t cause a reaction like that (foaming)… I don’t think. Must have been through the mouth. I’d guess your cat can now be considered a toad licker for sure. Did the keelback have bite marks all over it from the cat? If so, that cat might also be a snake licker.

      Hard to say… that cat is licking something though, of THAT you can be assured… :)

      1. No, I really didnt examine the snake, but of course should have. Should have also examined the toad for bite marks, but he looked so peaceful. Seems to be more and more snakes in the estate, but maybe I just can see them better now. Also I will leave the toads alone, and listen to the wife a little more.

        Thanks for your quick reply, Im sure I will have more questions later.


  4. Seen many in my garden in Chiang Mai, the juvenile was very cute, didn’t realize it was venomous, Packed in a bag, but it managed to escape.

  5. Probably in Tripura we called it Zinglapura Saap. Just now I have rescued one from my store room. I thought it is non-venomous. But after reading the article I came to know about it. This smale is really so good looking

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