1 Rouble Musk-Rat

Part of Russia's long-running wildlife conservation series, this rouble was issued when the Bank of Russia was expanding its commemorative program rapidly in the post-Soviet period — dozens of flora and fauna types appeared between 1993 and 2005. The musk-rat (Ondatra zibethicus) is not a native Russian species; it was deliberately introduced from North America in the 1920s as a fur industry animal and spread so aggressively across Soviet wetlands that it became one of the more consequential ecological introductions in Russian history.