Before the World War I there were over 700 specimens of European bison in the primeval forest of Bialowieza. During the war almost all bisons died or were killed.

In 1919 the last one of them was killed by poachers. In 1929 new pure-blooded specimens were brought to Bialowieza. Since then, the population of European bison in Bialowieza kept growing and in 2004 it reached 350 specimens.