50 Dollars - Elizabeth II European Bison with Calf'

Cook Islands issued a sprawling series of wildlife conservation coins in the late 1980s and early 1990s, many produced by the Pobjoy Mint under licensing arrangements that made the islands a vehicle for thematic collector issues rather than any domestic monetary policy. The European bison — wisent — had been declared extinct in the wild by 1927, surviving only in zoological collections before a painstaking captive-breeding program eventually reestablished wild herds in Poland's Białowieża Forest.

That recovery was still fragile in 1990, making the subject topical rather than merely decorative.