[1][2] Otto Fabricius was born in Rudkøbing on the island of Langeland, Denmark, where his father was a rector.
In 1765, he was admitted to the Greenland Mission Seminary (Seminarium Groenlandicum), where he attended classes taught by Poul Egede.
He had a few magnifying glasses and only one book was in his library, Linnaei Systema Naturae by Carl Linnaeus.
Nevertheless, he made enough zoological observation to be able to publish Fauna Groenlandica (1780), which was written in Latin, after his return to Denmark.
[4][5] In 1774, he was appointed rector at Drangedal in Telemark, Norway where he stayed until 1779 while he completed work for a Greenlandic language dictionary which was published in 1804.