The giant panda cub born Friday afternoon at the Smithsonian's National Zoo in Washington appears to be in good health after a quick physical examination on Sunday morning.

"All the external features looked perfectly normal, so the cub has been described as vibrant, healthy and active," Pamela Baker-Masson, a spokeswoman for the zoo, told reporters on Sunday.

"My colleagues were very, very happy. This is joyful news," she said.

Baker-Masson said Mei Xiang (pronounced May Sean), the panda mother, was agitated when the cub was taken away from her, pacing and growling in her den, but she calmed down immediately after the cub was returned to her and she began cradling it.

The zoo tweeted the news on Friday saying: "We have a cub!! Born at 5:32 pm this evening."

The abrupt delivery during labor was caught by the zoo's 24-7 webcam. It showed Mei Xiang scooping the tiny cub up and then cradling it against herself, a loving and protective mother.

The birth of new cub on Friday has brought huge excitement to both the staffers at the zoo and fans, who flocked to the webcam.

Zoo officials kept close watch on Mei Xiang throughout the night, as nearly half of giant panda births are twins. Sadly, news arrived 26 hours after the birth of the first cub that a stillborn twin cub did in fact arrive.

Mei Xiang was artificially inseminated by a Chinese expert at the end of March. The donated sperm came from Tian Tian at the National Zoo and a panda named Gao Gao at the San Diego Zoo.

"It is not known who is the father yet," Christine Kohl, a volunteer of the Asia Trail of the National Zoo, told visitors on Sunday outside the Giant Habitat, which has been closed to visitors since Aug 2 to create a more favorable environment for Mei Xiang's pregnancy.