The bear, which is saddled with heavy packs, symbolizes the weight of the papal office, the diocese said in a statement.
It has its origins in a Bavarian legend concerning the diocese's patron, Korbinian, who encountered the animal while on a trip to Rome. The bear ate Korbinian's mule, and God saddled it with the mule's packs.
The mussel dates back to a parable by St. Augustine -- about whose works the former Cardinal Joseph Ratzinger wrote his final thesis -- and symbolizes "diving into the groundless sea of God," the diocese said.
Read more: Pope's Coat of Arms Has Bavarian Elements