Description:A pair of twin polar bear cubs born at an aquarium in China have celebrated their first 100 days on earth. Born March 5 at Tianjin Haichang Ocean World, the baby bears spent their first days in an incubator, and staff were unsure if they would survive.
But now, the bear cubs are healthy and doing well. They celebrated their "100th-day birthday" by romping around with a ball.(0:58)