Ling-Ling and her new cub have settled into a comfortable mother-infant routine, and officials at the National Zoo said yesterday they were suspending their daily briefings on the cub's progress.
"If we were to call a news conference now, it would be for bad news," said zoo spokesman Robert Hoage.
"The next conference will be to announce a name for the cub, and that won't be for several weeks, maybe even months, until we can find out what sex it is."
The cub's continued survival would make it the first panda bred successfully in the United States.
Zoo keepers and veterinarians say the cub, born Tuesday morning, is following a fairly regular "sleep-nurse schedule," waking about every three hours to nurse from her 18-year-old mother.
"That's just what we want to see," said Hoage.
Ling-Ling appears to be getting back to normal, too.
Thursday night, she ate a carrot and drank some water.
Zoo authorities said they were relieved to discover that, according to an autopsy, Ling-Ling's other cub -- a male panda that had died a few minutes after birth -- showed no signs of bacterial infection.
"That's good news because it means the surviving cub is not suffering from any bacterial infection," Hoage said.
About 30 percent of panda births are twins.
There is no known case outside of China of both cubs living.
Ling-Ling has moved her cub out of camera range, so the mother and baby can no longer be seen on the zoo's closed-circuit television monitor.
But visitors to the zoo this weekend can view a special video highlighting the cub's arrival and replaying the few glimpses of the cub since then.