Dementiev was born in
Peterhof, where his father was a physician. He studied at the local gymnasium and joined the University of St Petersburg. Although interested in birds from a young age, his parents wished that he studied law. In 1920 he moved to Moscow to work as a lawyer. Although he had no formal qualifications in biology, he was well read and was fluent in French, German, Polish, Italian and Swedish. He began his research under
Mikhail Menzbier and joined the museum at Moscow in 1927 to join
S.A. Buturlin to work on a guide to the birds of the USSR which was published in 1934–40. He became a curator in 1932 and stayed in the position until 1947 when he joined the biology department. He was mostly into museum ornithology and was an expert on identification and taxonomy taking a special interest in the birds of prey, especially the falcons. The six volume
Birds of the Soviet Union published with N.A. Gladkov between 1951 and 1954 is still a major reference. In 1952 he was appointed by the Soviet Academy of Sciences as Vice Chairman of the Commission on Nature Reserves which later became the Commission on Nature Conservation. He was elected Honorary Vice-president at the Fifth IUCN Assembly at Edinburgh in 1956. Dementiev was married to Maria Grigorievna Golubeva (1900–1970) and their daughter Maria Georgievna Vakhrameeva became an evolutionary biologist. ==References==