In Vietnam, there is a snake species known by the nickname “Queen of the Night.” Although it is a member of the water snake family, it possesses extremely dangerous venom that can be fatal.
The Snake Dubbed the “Queen of the Night” in Vietnam
The snake referred to above is the red-necked keelback, scientifically named Rhabdophis subminiatus, a species belonging to the keelback genus in the water snake family.
In Vietnam, this snake is known by various names, including red-necked water snake, flat-necked snake, and red-striped snake, but it is most widely recognized as the Queen of the Night, Fire Tiger, and Student Snake.
The red-necked keelback snake features a prominent red neck, which is the origin of its name (Photo: GBIF).
The red-necked keelback is a medium-sized snake, with a body length ranging from 0.8 to 1 meter, with females being significantly larger than males. There is a clear distinction between the head and neck. This snake typically has a blue-black or gray-black body, with a darker head and black markings on the front half of the body. Juvenile snakes often have distinct yellow and black bands around their necks, but these markings fade as they mature.
The most notable characteristic of the red-necked keelback is the section of red scales around its neck, making it easily identifiable. This feature also contributes to its names, such as red-necked keelback or student snake, as it reminds many people of the red scarves worn by students.
Juvenile red-necked keelbacks have distinct yellow and black bands around their necks. These markings fade as the snake matures (Photo: Animalia).
The red-necked keelback is widely distributed across Southeast Asian countries and China.
In Vietnam, this snake is found throughout nearly all provinces and cities, with two subspecies, including the Siamese red-necked keelback and the He-le red-necked keelback (or Northern red-necked keelback). The He-le red-necked keelback is found in the northern region and the North Central area, while the Siamese red-necked keelback is distributed in the South Central region and southern provinces.
The red-necked keelback is a semi-aquatic snake, typically inhabiting areas near water, such as rice fields, ponds, lakes, slow-flowing rivers, and irrigation ditches. This snake is often found in residential areas, leading to frequent encounters with humans.
This species is diurnal and spends most of its day hunting. Its primary diet consists of frogs, toads, and fish.
How Venomous is the Red-Necked Keelback?
As mentioned earlier, the red-necked keelback belongs to the water snake family, which leads many people to believe it is non-venomous. However, in reality, the red-necked keelback has highly dangerous venom that can be lethal.
The red-necked keelback can raise its head and expand its neck to threaten enemies (Photo: Shani Cohen).
The red-necked keelback is a generally docile snake that tends to hide when confronted by humans. When threatened or agitated, the red-necked keelback can raise its head, flatten its neck, and coil into an “S” shape to prepare for a defensive bite to intimidate its foe.
This species has rear fangs, meaning its venom-delivery fangs are located deeper inside the upper jaw, near the throat, rather than situated at the front like most other venomous snakes.
Because the fangs are positioned deeper inside, the red-necked keelback and other rear-fanged venomous snakes often need to bite deeply into their prey or enemy to inject venom effectively. This makes the venom delivery of rear-fanged snakes less effective compared to front-fanged species.
Types of fangs in venomous snakes (from left to right): rear fangs, fixed front fangs, and hinged fangs (Photo: SA).
Due to the design of its rear fangs, the red-necked keelback often delivers dry bites without injecting venom. This has led many to mistakenly believe that the red-necked keelback is harmless and venom-free.
However, if bitten by a red-necked keelback in areas such as between the fingers, toes, or on small children’s hands and feet (where the bite can penetrate deeply), the victim can be at risk of being injected with venom.
Venom fangs of the red-necked keelback are positioned deep within the jaw and are rarely used (Photo: Mahidol).
Currently, there is no specific antivenom developed for the red-necked keelback’s venom. The main reason is that the red-necked keelback is a gentle species, has rear fangs, and rarely injects venom when biting, making antivenom research not particularly essential. However, if envenomated by a red-necked keelback, the victim can potentially be fatal.
If bitten by a red-necked keelback, it is crucial to immediately take the victim to the nearest medical facility. Although there is no antivenom, doctors can treat the patient based on symptoms to help counteract the poisoning.
A Second Toxic Gland Located in the Red Neck
One unique aspect of the red-necked keelback is that it possesses not only venom glands to inject into enemies through its fangs but also a toxic gland located in its red neck.
The red scales on this snake’s neck can secrete toxins, which can be dangerous to humans if ingested or if they come into contact with the eyes (Photo: HKSnakeID).
When threatened or in danger, this snake can secrete toxins from its red neck by rupturing the toxic glands beneath the skin. These toxins are accumulated from toads, the red-necked keelback’s favorite prey. The toxins from this snake’s neck can be hazardous if accidentally ingested or if they come into contact with the eyes.
Therefore, if you encounter a red-necked keelback, it is advisable to simply drive them away rather than attempting to capture or kill the snake to avoid the risk of being poisoned by the toxins secreted from its red neck.
Dangerous Misunderstandings and Accidents Involving the Red-Necked Keelback
Many people mistakenly believe that the red-necked keelback is a harmless water snake and have captured and kept this species as pets in their homes. This dangerous misunderstanding has led to unfortunate accidents.
The red-necked keelback has vibrant and eye-catching colors, but it should never be kept as a pet to avoid unfortunate accidents (Photo: Biodiversity).
For instance, in 2021, a 3-year-old boy in Ho Chi Minh City was bitten by a red-necked keelback on his hand, resulting in his death. Previously, the boy’s grandfather had kept a red-necked keelback, mistakenly believing it to be a harmless snake, but ultimately the boy was bitten on the back of his hand, leading to his death.
There have been numerous cases where people played with or captured red-necked keelbacks, thinking they were gentle and harmless. This has led to the risk of being bitten by a red-necked keelback, which can potentially be fatal.
With the information provided in this article, we hope that everyone will be more cautious when encountering the red-necked keelback, limiting contact with this species to avoid being bitten or exposed to the toxins secreted from its red neck.
