Karaganda/Siberian Pit Viper Gloydius halys

The Siberian Pit Viper, also Halys' Viper, is native to a vast range of Russia, east of the Urals, Central Asia and China. It has several subspecies over its range: shown is the Karaganda Pit Viper, G. h. caraganus, prevalent from southeastern Russia via Central Asia to northwestern China. It grows to some 2 feet (60 cm) in length. Photos thanks to Alexandra Makhnina, taken in Kazakhstan.

Like all pit vipers it has a heat-sensing pit on its face and a highly poisonous bite. Note how, over the course of the photos, it uncoils its tail, moves to the clover, raises its head and coils its head and body like a spring ready to strike.