The National Zoo's giant panda cub has doubled in length since his first examination two months ago and could be crawling around within two weeks, the animal park's chief veterinarian said yesterday.

During his seventh medical examination yesterday morning, the cub measured 24.7 inches long, compared with 12 inches during his first exam Aug. 2. He weighed 11.1 pounds, compared with 1.82 pounds at his first checkup.

"He's the incredible expanding panda," said chief veterinarian Suzan Murray.

The panda cub, born July 9, is 12 weeks old today. The indoor areas of the Panda House are closed to the public until at least November, though the two adults -- father Tian Tian and mother Mei Xiang -- sometimes can be seen outdoors. The name of the cub, chosen in a contest that ended yesterday, will be announced during a ceremony Oct. 17.

Born with his eyes closed and with no fur to defend himself from the cold, the cub now can see and is a fully furred miniature version of a black-and-white adult. One big landmark in his development will be his ability to move around. He took a couple of steps Thursday but quickly fell over on his side. During yesterday's exam, he tried to get up and crawl but could not quite manage.

"He is trying to get his hind legs under his belly . . . but not quite able to get liftoff," Murray said. "I think that we're a week away from the belly achieving liftoff, maybe two weeks."

Murray said it now takes two to four hands to hold the cub for an exam -- a sign of his expanding size. All signs looked good during the 14-minute examination, she said, including a fat belly she likened to "a very solid water bottle."

Through her gloved hands, she could feel teeth buds about to erupt beneath the animal's gums. The cub made noises halfway between a chirp and grunt, she said, but barely reacted when she gave him his second vaccination against the canine distemper virus. Neither he nor his mother, who was in another part of the Panda House during the exam, seemed alarmed, she said.

Murray and other zoo staff members performed the exam before an audience inside the Panda House that included Smithsonian Secretary Lawrence M. Small, Undersecretary for Science David L. Evans, their wives and several other high-level officials who saw the cub for the first time.

"He's just beautiful, like a big, cuddly bundle," said the zoo's deputy director, Mary Tanner, who said a keeper carried the baby in a plastic container past the group of dignitaries so they could get a close look. Tanner said she could hear the sound of the cub's claws scrabbling on the examination table.

Tanner said she had a "heartwarming, giddy feeling" as she watched the examination. And, when keepers carried the cub back to his den after the checkup, she and the others quietly applauded.

The zoo's panda cub has "increased two Tupperware sizes" since his first exam Aug. 2, chief veterinarian Suzan Murray says.