Tag Archives: Rhabdophis subminiatus

Red Necked Keelback – Venomous – Dangerous

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

Rhabdophis subminiatus (Red-Necked Keelback Snake)

Thai: (ngoo lay sab ko dang)

Length: Up to 130 cm (1.3 meters). Usually smaller than 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 toads, and fish.

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, I for one have never seen this in the wild or with snakes in captivity and I’ve seen dozens of them.

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 (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 from eating poisonous 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 ANTI-VENIN available yet for these snakes in Thailand.

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.

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, which probably can also inflict a medically significant bite if given the opportunity.

Classification:

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

Red Necked Keelback video

Red Neck Keelback Snake ( <- click) video – This is another red-necked keelback (adult) that I had for a while. I’ve since let it go back into the wild.

Snake Bite – Red-Necked Keelback – Rhabdophis subminiatus

A couple months back I received an email from a concerned father whose son was bitten by a red-necked keelback (Rhabdophis subminiatus) he had found in their neighbor’s garden.

“My son is suffering from non clotting, severe swelling, and paralysis and is now in ICU, where his vital and neuro signs are ok, but blood not good.”

These snakes have, in the past, not been identified as a dangerous snake. Many people have them as pets, and free-handle them with bare hands. Sometimes these snakes bite, but once they are handled a bit they usually calm down and rarely bite. There have been some cases in the literature where bites have resulted in hospitalization, and there has been a push to identify these snakes as what they are – venomous, and dangerous.

Colubrids, rear-fanged snakes, are nearly all venomous. Venom is modified saliva that helps the snake kill and break down the body of their chosen food.

I was excited to have a response from the father of this boy that spent 2 weeks in a Thailand hospital after suffering 2 bites from this snake.

Here’s what I learned after some questions by email…

1. Can you tell anything about how the bite occurred? Was the snake typically calm – and then, out of the ordinary behavior – it bit your son?

Calm, he was showing off to his friend’s that he can handle snakes, this was a wild one not a pet. He has a constrictor, a corn snake and a python as pets, all fairly placid, but the keelback he had no understanding of.

2. Approximately how long did the snake bite down on your son’s hand? Was it less than 1 second? 1-3 seconds? 3-5? 10? 60 or more? This is the most important question because in the past we haven’t seen enough venom transferred from quick bites, or even repetitive quick bites…

Between 30-40sec I believe, wouldn’t let go

3. Did the snake bite more than once that day?

Bit him twice within a few minutes.

4. Did the snake routinely bite your son – often?

First time.

5. Can you tell me approximately how long was the snake? Do you have any photos of it? Can you please send if you do?

No photo’s I’m afraid, he didn’t mention how long it was, but he will be back from school at the weekend, and I’ll fish more info out of him.

6. Did you get the snake in Thailand? There in Phuket, or where?

Wild snake in his friend’s garden.

*******

So, here again – the snake bit down for an extended period of time – 30+ seconds, and had time to squeeze a lot of venom into the boy’s hand.

There is no known anti-venin for the Rhabdophis subminiatus as it is here in Thailand. In Japan there is a small amount of antivenin produced for their local species. To my knowledge there has been nobody treated with this antivenin outside of Japan, and I’m sure they would not be all that interested to give up some of their small supply to export to another country.

More information on venom toxicity and treatment after bite by this snake: R. subminiatus.

Venom Characteristics (from http://www.afpmb.org/content/venomous-animals-r#Rhabdophissubminiatus)

Mainly procoagulants, which can cause renal failure; plus mild neurotoxic factors. Envenomation does not always occur. Bite may be almost painless w/ minimal local swelling. Symptoms of envenomation may include local numbness, headache, nausea, & vomiting; in severe cases renal failure has caused human deaths. No known antivenom currently produced.

LD50 for intravenous injection – .125 to .129 mg/kg. That is extremely venomous, in the same category as Bungarus candidus (Malayan Krait), Naja kaouthia (Monocled Cobra), and O. hannah (King Cobra).

Red Necked Keelback Caught on a Night Herping Trip

Just a pic – wanted to share this Thailand snake before I forgot….

Rhabdophis subminiatus, Red-necked keelback. Venomous and dangerous.

A boy, 12 yrs old, in Phuket, Thailand was in the Bangkok hospital for 2 weeks after a bite from this snake. The venom specifically attacks the kidneys.

Once thought to be harmless – these snakes are now considered dangerous. Don’t have one as a pet…

Rhabdophis subminiatus, Red-necked keelback snake from southern Thailand
Beautiful and dangerous...