Krüper was born in Ückermünde in Pomerania where his father was a merchant. He went to the local schools before going to high school in 1844 to Stettin after which he went to the University of Berlin. As a child he began collecting butterflies and birds eggs and peaked at high school after meeting Carl August Dohrn. The lepidopterist Erich Martin Hering also inspired him and Martin Carl Heinrich von Lichtenstein, privy councillor in Berlin entrusted Krüper with the egg collections at the museum offering him a position to deal with the mollusc collections. Von Lichtenstein's death in 1857 prevented this. Otto Staudinger who was also studying in Berlin became a close and lifelong friend of Krüper. In 1856 he explored northern Iceland while Staudinger spent time in the southern part. In 1855 he travelled with natural history dealer Keitel from Berlin. He visited Iceland again in 1856 and Gothland in 1857 where he also obtained fossils. In 1872 he became a curator at the University Museum in Athens. He then collected extensively in the Mediterranean region covering Macedonia, Smyrna, Constantinople and the Kyllene Mountains. He published extensively in the journals Naumannia and the Journal für Ornithologie. Krüper lived with an Athenian woman from 1864 but at the time of his death in Athens they were childless and his collections were transferred to the Athens museum.[2][3]
