One of outstanding Soviet zoologists, head of Moscow school of mammalogy after Ognev's death. He graduated from Natural History Department of Moscow University in 1923 and was kept at its Zoological Division. Appointed curator of vertebrate collections in 1927 and chief of Mammal division of the Museum in 1932. Remained at this position by 1950 and then moved to the Department of Vertebrate Zoology still remaining scientific patron of the Museum mammalogy.His research interests were in taxonomy and fauna of mammals of the USSR, as well as in nature protection. He participated in many expeditions to Caucasus and Middle Asia. Read course on zoogeography and published fundamental textbook on that subject. Continued Ognev's serial on the USSR mammal fauna, issued 4 books on larger mammals. Contributed much to introducing ideas of “The New Systematics” to Soviet zoologists by promoting and editing several books of its leader, E. Mayr.