The National Zoo welcomed a rare new addition late Sunday night with the birth of a giant panda cub, and officials said Washingtonians will get a chance to name it.

Zoo officials said Monday afternoon that they said they had caught "glimpses" of the cub -- about the size of a stick of butter and 1/1000th the weight of its mother -- and wouldn't know its gender until they examine it. The next few weeks are critical for its health, but officials said they are optimistic.

"It came out healthy, it's yelling healthy," said National Zoo Director Dennis Kelly.

What's in a name?
The National Zoo let the public vote online for one of four names for its previous panda cub, born in 2005. The winning name, Tai Shan, means "peaceful mountain" and garnered more than 202,000 votes. But just after its birth, the cub became known as "butterstick" after a zoo keeper compared its size to a stick of butter. The moniker became so popular that some panda fans even called for "Butterstick" to be added to the name options.

He added that as they did in 2005 with 14-year-old Mei Xiang's first cub, Tai Shan, the zoo plans to let the public get involved.

(View a photo gallery of mother Mei Xiang and Tai Shan, the last giant panda cub born at the zoo)

"Everyone in Washington will have the chance to name this cub, so stay tuned," Kelly said Monday.

The zoo will follow Chinese tradition of waiting 100 days to name it, and Kelly said no details have been worked out yet. In 2005, the ran an online poll letting voters choose between four names, all approved by the China Wildlife Conservation Association.

The panda house will be closed to the public for at least the next few weeks to allow the mother to connect with her cub in private, officials said.

Nicole MacCorkle, one of the keepers who has been monitoring the cub on the zoo's 24-hour panda cam, described it as "very active and vocal." She said the cubs are typically born weighing about 4 ounces, are hairless and pink. The staff is waiting to examine the cub until after Mei Xiang bonds with it.

When the panda house reopens, the attention given a giant panda cub means a potentially 25 percent attendance boost for the zoo. When Tai Shan was born in 2005, officials said they saw an extra 500,000 visitors in addition to the 2 million people who visit annually.

Although officials would not place a dollar value on its potential boost in business, they said that every visitor represents additional concessions revenue for the institution, which does not charge admission. The money visitors spend at the zoo helps fund its scientific research on pandas and conserving the species.

Kate Brantley and Martha Abshire were at the zoo Monday, visiting for the day from Baltimore. They said they "definitely" planned to come back to see the cub. Abshire saw Tai Shan just before he was returned to China in early 2010.

"They were really rambunctious and happy," she said of the panda and its mother. "It was awesome."

Video footage of the birth from the zoo's Panda Cam:

The new cub was born at 10:46 p.m. Sunday and marks Mei's second cub from artificial insemination. After natural mating failed this year, Mei was inseminated in April with semen from her mate, Tian Tian, that had been frozen in 2005, zoo keepers said. The zoo's adult giant pandas and any cubs they produce are all property of the Chinese government. This pair of adults have been on loan from China since 2000 and will stay until at least 2015, according to an agreement between China and the zoo.

Giving birth in captivity is rare -- Mei had a less than 10 percent chance of conceiving via artificial insemination and she has had five false pregnancies since 2007.

"It's still kind of sinking in for us right now, I think," MacCorkle said.