ROYAL OAK, Mich. -- Three grizzly cubs orphaned when their mother was shot dead on the Anchorage Hillside have arrived at their new home at the Detroit Zoo.

The zoo in the Detroit suburb of Royal Oak says the bear cubs arrived by plane this morning at Detroit Metropolitan Airport in Romulus aboard a Federal Express plane from Anchorage.

The cubs had been living at the Alaska Zoo. They were roaming the Anchorage Hillside until they were brought in by state officials.

One of the cubs arrived on Halloween, and keepers named him Boo. His brothers were brought in the following weekend and named Thor and Mike. They're about a year old.

The cubs are in 30-day quarantine. Detroit Zoo visitors likely will be able to see them in January.