U.S. Fish and Wildlife Service spokesman Bruce Woods says the bear's mother was killed March 12 on Alaska's northwest coast, but it wasn't immediately clear if the shooting was subsistence or defense related.
Woods says the man who shot the bear brought the cub to authorities, and it was ultimately transferred to Anchorage for care.
The cub is about 3 or 4 months old and weighs just over 18 pounds (8 kilograms).
The bear isn't currently on display. The wildlife service will eventually place the cub somewhere else since the Alaska Zoo already has two polar bears.