Surprise: A study reveals five distinct Himalayan viper species

A re-examination of museum specimens or living individuals sometimes yields surprises. In the case of the Himalayan pit viper, it revealed that there were not two, but five species of this venomous snake.

G. hazarensis, hindukushensis, and nepalensis

The boundary between two species can be thin. When their physical differences are almost non-existent, genetics, geographic ranges, or distinct life histories can help distinguish them. Recently, an international team of researchers focused on seven Himalayan vipers collected between 2015 and 2023, as well as 11 museum specimens.

Known to science since the late nineteenth century, the Himalayan pit viper (Gloydius himalayanus sensu lato) is found only in the Indian Himalaya. Taking shelter under leaf litter, tree trunks, or stones, it sometimes nests near human dwellings. Described in 2022 and for a long time confused with the former species, G. chambensis is, meanwhile, endemic to the moorlands and pine forests of the western Himalaya and the Kashmir Valley.

The first of the three new species is the Hazara pit viper (G. hazarensis), previously observed only in northern Pakistan. Preferring cooler habitats, it is thought to occasionally prey on small birds. Found on the eastern slopes of the Hindukush, near the Afghan border and along the Indus, G. hindukushensis lives at even higher elevations, characterized by substantial snowfalls in winter.

As its name implies, the Nepal viper (G. nepalensis) inhabits high-altitude meadows and shrublands in the western and central parts of the country. Capable of hibernating for up to seven months depending on local conditions, it preys mainly on frogs, lizards, and rodents.

Natural barriers

According to the authors of the new study, published in the journal ZooKeys, the terrain features and the large surrounding river valleys helped drive the separation of these distinct populations, which developed unique genetic adaptations and occupied separate ecological niches.

“The fact that people long believed there was only one Himalayan viper species reflects the remoteness and wild nature of these environments, as well as delicate political contexts that have complicated fieldwork,” they conclude.

In 2024, similar analyses had shown that there were not one, but four species of the king cobra.