Zoo keepers are on 24-hour birth watch for a new giant panda at Zoo Atlanta. They expect 10-year-old giant panda Lun Lun to deliver a cub in the next few weeks.

Lun Lun showed a decrease in appetite and became lethargic last week. Keepers say the changes are normal for a female giant panda entering the final phase of pregnancy.

Lun Lun's first cub named Mei Lan was born on Sept. 6, 2006. Zoo Atlanta is one of only four zoos in the U.S. exhibiting the endangered species.