Gloydius himalayanus

Gloydius himalayanus (commonly known as the Himalayan Pit Viper) is a medium-sized gray-brown snake found in caverns and rocky crevices of forested hill sides, where it feeds on skinks and lizards. The scale pattern consists of medial dark brown blotches, alternating with lateral rows of spots.
It occurs along the southern slopes of the Himalayas from Kashmir to Nepal as far as Sikkim between 1500–3000 m altitude.
The Himalayan Pit Viper is a habitually sluggish snake that basks in sunlight and hibernates in winter.