Thankfully these two have a lot of history.
The pair were rescued together along with four other bears from a bile farm in China.
The scene was typical of the horrific industry. Rows of bears were confined in tiny cages so that the liquid from their gall bladder could be painfully extracted and used in traditional medicines.
At least 12,000 bears continue to suffer such an awful fate in Vietnam and China.
Peter and Shamrock are just two of the 500 bears Animals Asia has rescued and rehabilitated on their sanctuaries.
And this kind of play fighting is a regular part of sanctuary life for rescued bears, being a primary source of fun, friendship and exercise.