Pallas' Pit Viper

Gloydius halys, commonly known as the Siberian pit viper, Halys viper, or Pallas' pit viper, is a venomous pit viper species indigenous to Asia. These snakes can be found across a broad range of locations, from Russia to China, and extending to parts of Iran, Mongolia, and Japan.

There are five recognized subspecies of Gloydius halys, but we will focus on the primary one. These snakes are relatively small, with females reaching up to 59 cm (about 23 inches) in length and males up to 53 cm (about 21 inches). They possess a moderately stout body and a slightly upturned snout, giving them a distinctive appearance.

Their coloration ranges from grayish to yellowish, adorned with dark spots or crossbars along their back, and smaller dark spots on their sides. Their belly is whitish, speckled with gray or brown. The scales are strongly keeled and arranged in 23 rows around the midsection of their body, contributing to their unique texture.

Gloydius halys was first described from a salt lake near the Upper Yenisey in Siberia, Russia. However, in 1993, Bour redefined this type locality to be near the Russia-Kazakhstan border.