On an expedition to the Syr Darya, he was captured by bandits and freed after a month. In 1865-68, he explored the Tian Shan mountains and Lake Issyk Kul. In 1877-78, he explored the Pamir Mountains, following a route close to the current Pamir Highway as far as Lake Yashil Kul on the Ghunt River.
Severtzov wrote the Vertical and Horizontal Distribution of Turkestan Wildlife (1873), which included the first description of a number of animals. Among them is a subspecies of argali (wild sheep) later named after him: Ovis ammon severtzovi. He also described many new species and subspecies of birds. The Spotted Great RosefinchCarpodacus severtzovi is among those named after him.