Porshnev took interest in cryptozoology and has been described with Marie-Jeanne Koffman as the revered parents of Russian monster-hunting. Porshnev led several Soviet expeditions to the Pamir Mountains and north-western Himalayas to search for the Mongolian Almas (wild man). He was driven by a Marxist ideology to find the wild man to confirm materialism and evolutionary human origins. He believed that the almas were a relict population of the Neanderthals who had survived the Ice Age of the Pleistocene epoch. His expeditions were unsuccessful and his career went into decline.