These stamps show the European Bison. It is considered our national animal. The European Bison is the biggest mammal living in the wild in Europe. It was almost extinct. After the 1st World War only several dozen of them survived and only in the zoos. In 1923 Poland went out with the initiative to restore the species. All living nowadays European Bisons originate only from 12 individuals. The biggest number of European Bisons live of course in Poland.
Now about the stamps. What is special about them - when you rub them they smell of forest:) They were issued in 2011 and this year they won International Awards for Philatelic Art.