The 22nd Transport Company, Artillery Division Polish II Corp, was a unit that fought for the Soviet Union. Previously they were prisoners of war, but with the German invasion of Russia, the Poles were set free and re formed into combat units to join with the British Expeditionary Force.
While in Iran, the unit came upon a boy who had a circus trained bear and exchanged the bear for food. One might thing that the bear would suffer as a result of the exchange, but the unit took to it and gave it a name “Wojtek” or “Smiling Soldier”. The bear was young when the troops came upon him but they fed it and for lack of a better term, raised this bear on the move in the war.
The bear garrisoned with the men, and played with them apparently without causing too much harm. It played tug of war and was friendly with the dog of a British liaison officer. Wojtek drank beer, and smoked and consumed cigarettes.
As the unit came upon the war itself in Southern Italy, they decided to keep him within their ranks, and he carried heavy shells up the torturous mountain passes and even participated in the assault on Monte Cassino. Once officials refused to allow Wojtek to board a ship because he was an animal. So they gave him a rank and a serial number and taught him to salute and on board he went to Naples, into the war zone.
When the war ended Wojtek was placed in the zoo in Edinburgh. From time to time Polish solider would travel to see him and jump the fence and feed him beer. He is said to have perked up when he heard Polish spoken.
He died in 1963 at the age of 22.
Sources: Wojtek, the Bear, Aileen Orr, Neal Ascherson, Berlinn Limited. 2010., wiki.