ROYAL OAK, Mich. -- Three orphaned grizzly bear cubs that came to the Detroit Zoo from Anchorage in December have made their public debut.

Mike, Thor and Boo spent the winter "denned up," as they would in the wild.

On Thursday, the 14-month-old brothers met their public. They explored their new habitat, including having a dip in the 6-foot-deep pool, and did a little roughhousing.

The three were orphaned in October and captured by the Alaska Department of Fish and Game after their mother was shot and killed in Anchorage by a Wasilla man.

Alaska wildlife officials contacted the Detroit Zoo after determining the cubs couldn't survive the winter on their own.

The cubs have nearly doubled in size. They now measure about 4 1/2 feet tall and weigh between 215 and 255 pounds.