Zoo staff saw the cub's eyes beginning to open during an inspection on Wednesday. Officials say it will likely take 20 more days for the eyes to fully open.
The cub weighs 4 pounds and measures a little over 16 inches long, and animal care staff members are pleased with his growth, which shows that the baby is nursing well from his mother.
The zoo follows the Chinese cultural tradition of naming the panda after it is 100 days old. Starting Sept. 17, the San Diego Zoo Global Wildlife Conservancy will begin taking name suggestions for the boy cub on its website, www.sandiegozooglobal.org.
The names must be submitted in Chinese pinyin, which is the official system to transcribe Chinese characters into Latin script, and the significance of the name must be included in the submission. The zoo will take submissions until Sept. 24.