Despite its name, the Horned Pit Viper does not have the typical green scales associated with its common name. Instead, it possesses a fearsome appearance with a pair of horns on its head.
Native Venomous Snake Species in Vietnam
The creature mentioned above is the Horned Pit Viper, also known as the Fan-si-pan Horned Viper, scientifically named Protobothrops cornutus.
Although it has “viper” in its name, this snake does not have green scales; instead, it has a body covered in brown-gray scales, with a dark stripe running along its back and lighter brown sides. This coloration allows the Horned Pit Viper to camouflage effectively within its habitat for hunting prey and evading natural predators.
The Horned Pit Viper has a clearly differentiated head and neck, with a long and slender body (Photo: iNaturalist).
Like other species in the pit viper family, the Fan-si-pan Horned Viper has a large triangular head, distinctly separated from its neck and body. This species is small in size, with males generally smaller than females. Adults typically measure between 0.6 to 0.9 meters in length and weigh between 0.6 and 1.3 kilograms.
A notable feature of this snake is the two raised scales above its eyes, resembling sharp horns. Males usually possess larger “horns” compared to females. This characteristic contributes to the snake’s fearsome name and appearance.
The scales above the eyes of this snake are raised, resembling a pair of horns, giving it its name (Photo: Research Gate).
Habitat and Diet of the Fan-si-pan Horned Viper
The Fan-si-pan Horned Viper typically inhabits limestone mountainous regions or granite outcrops, humid forests, and tropical woods at elevations ranging from 250 to 2,000 meters.
In Vietnam, this snake is found in Lao Cai (Sa Pa, Van Ban), Ha Giang (Khau Ca), Cao Bang (Ha Lang), Ninh Binh (Hoa Lu), Quang Binh (Phong Nha – Ke Bang National Park), and Thua Thien Hue (Bach Ma National Park). It is a rare species with fragmented and scattered habitats.
The Fan-si-pan Horned Viper is nocturnal. This behavior helps it avoid potential predators in the wild. During the day, this snake usually hides in tree hollows or under dense foliage, using its coloration for effective concealment in its environment.
The coloration of this snake helps it camouflage well in its habitat (Photo: Yan).
This species hunts at night. Thanks to the heat-sensing pits on its face, the Horned Pit Viper can hunt in darkness by detecting the body temperature of its prey.
It primarily feeds on small mammals, birds, lizards, and frogs. This snake employs an ambush hunting strategy, patiently waiting for prey to come close before striking, injecting venom, and consuming its meal.
How Venomous is the Fan-si-pan Horned Viper?
The Fan-si-pan Horned Viper belongs to the Crotalinae subfamily of pit vipers, possessing highly dangerous venom.
When bitten, victims experience intense pain, swelling, and coagulation disorders leading to continuous bleeding. If not given timely medical attention, it can result in tissue necrosis or even death.
However, due to the Fan-si-pan Horned Viper’s preference for high altitudes in areas with few human inhabitants, encounters between people and this snake are rare, resulting in few recorded bites on humans.
Conservation Status of the Fan-si-pan Horned Viper
The Horned Viper is a rare species that needs conservation (Photo: oldfears).
Due to habitat fragmentation and degradation caused by stone exploitation, mining, and encroachment on forest land, the Fan-si-pan Horned Viper is facing threats to its survival.
Currently, the Fan-si-pan Horned Viper is listed as “vulnerable” in Vietnam’s Red Book, classified as a rare species at risk of extinction if negative impacts on its habitat continue. Therefore, Vietnamese law prohibits the hunting and trade of this snake.
