The cobra is one of the most fearsome venomous snakes in the world. Consequently, many harmless snake species mimic the defensive behavior of cobras by raising their heads and expanding their necks to intimidate potential threats.
Harmless Snakes “Pretending” to be Cobras to Deter Enemies
When talking about cobras, many people immediately think of these frightening venomous snakes that can raise their heads high and flare their necks to threaten foes. This characteristic allows humans to easily identify extremely venomous cobras and stay away from them.
Cobra species are characterized by their ability to raise their heads and flare their necks to threaten enemies (Photo: iNaturist/TNP).
Several harmless snake species have adopted the cobra’s defensive appearance to intimidate their enemies. One such species is the large-eyed pit viper.
The large-eyed pit viper, scientifically known as Pseudoxenodon macrops, is a species belonging to the genus Pseudoxenodon, which is part of the water snake family. This species is endemic to Asia, found in countries including Vietnam, China, India, Nepal, Myanmar, Laos, and Thailand.
A specimen of the large-eyed pit viper with an inverted “V” shape on the back of its neck, photographed in Phong Nha-Kẻ Bàng National Park, Quang Binh Province (Photo: Bernhard Forster).
In Vietnam, this snake species is distributed in high mountainous regions of Lao Cai (Sapa), Lang Son (Mau Son), Vinh Phuc (Tam Dao), Quang Binh (Phong Nha-Kẻ Bàng), Hue (Bach Ma), and Lam Dong (Ba Na)…
This species typically inhabits dense forests near streams, at altitudes ranging from 500m to 1,500m above sea level. This is why humans rarely encounter or come into contact with the large-eyed pit viper.
True to its name, the large-eyed pit viper has notably large eyes that stand out on its face, with round pupils. The snake has a head that is not distinctly separate from its neck.
The large-eyed pit viper features large eyes with round pupils (Photo: Rohit Naniwadekar).
The large-eyed pit viper is a small-sized snake, with an adult length of only about 80cm to 120cm. The snake typically exhibits brown, gray, or sometimes orange and green colors, with crosswise stripes along its body. The back of the snake’s neck has an inverted “V” shape pointing towards its head. This coloration allows the large-eyed pit viper to easily hide and camouflage while hunting or evading predators.
The large-eyed pit viper is diurnal, actively hunting during the day. Its primary diet consists of lizards and amphibians, such as frogs and toads.
Is the Large-eyed Pit Viper Venomous?
In the natural world, animals have various ways to survive. Some possess venom to kill predators, while others find ways to camouflage themselves to escape. Additionally, some species mimic the physical characteristics of venomous species to intimidate threats, and the large-eyed pit viper is one such example.
When threatened, the large-eyed pit viper raises its head and flares its neck to resemble a cobra (Photo: Rohit Naniwadekar).
The large-eyed pit viper is a gentle snake that always seeks to avoid confrontation. When threatened, it will raise its head and try to expand its neck to make its appearance similar to that of a cobra. The pattern on the back of its neck also enhances its resemblance to a cobra.
While predators might hesitate, thinking they are facing a cobra, the large-eyed pit viper seizes the opportunity to escape.
In fact, the large-eyed pit viper does possess venom and is classified as a rear-fanged snake, meaning that its fangs, which inject venom, are located deep inside the upper jaw, near the throat, rather than being positioned externally like most other venomous snakes.
Due to the deep positioning of its fangs, the large-eyed pit viper and other rear-fanged venomous snakes typically need to bite deeply into their prey or enemies to position their fangs correctly for venom injection. This leads to the venom delivery of rear-fanged snakes being less effective compared to front-fanged venomous species.
The defensive posture of the large-eyed pit viper often leads to it being mistaken for a cobra, resulting in its frequent elimination by humans (Photo: Leonid A. Neymark).
When attacking, the large-eyed pit viper typically delivers a dry bite, meaning it does not inject venom. Furthermore, the venom of this species is quite weak and not sufficient to pose a danger to humans. Therefore, the large-eyed pit viper is harmless to people.
Although the large-eyed pit viper is naturally gentle and always seeks to avoid humans, its tendency to mimic cobras when threatened often results in human casualties when encountered. This is because not everyone possesses the knowledge or composure to distinguish between the harmless large-eyed pit viper and the venomous cobra.
Despite resembling a cobra in its defensive posture, the large-eyed pit viper can be easily identified by its large eyes (Photo: TNP).
Of course, distinguishing between different snake species to determine their venomous nature is complex and not everyone has the requisite knowledge to do so. Therefore, when encountering a snake and unsure whether it is venomous, it is best to keep a safe distance rather than attempting to catch or attack it to avoid potentially dangerous snake bites.
