Gloydius himalayanus is a venomous pit viper found along the southern slopes of the Himalayas in Pakistan, India and Nepal. Also known as the Himalayan pit viper, it holds the distinction of being the highest-living snake ever recorded, with individuals encountered at elevations up to 4,900 metres above sea level.
The species belongs to the genus Gloydius, a group of Asian pit vipers characterised by heat-sensing pits located between the eye and nostril that allow them to detect warm-blooded prey in cold, high-altitude environments. Its ability to survive at such extreme elevations places it among a select group of reptiles adapted to the thin air, intense ultraviolet radiation and freezing temperatures of the high Himalayas. No subspecies are currently recognised, though populations across its range occupy varied terrain from forested valleys to rocky alpine slopes. The Himalayan pit viper’s physiological adaptations to altitude remain of interest to researchers studying the limits of reptilian survival in mountain ecosystems.
