It's a sad goodbye this morning for the many, many admirers of four-year-old Tai Shan and three-year-old Mei Lan, two pandas born at zoos in the United States
This morning, they left on a charter plane for a roughly 14-hour flight to China. It's a heartbreaking deal: Every panda living in the U.S., even those born here, must eventually be returned to their motherland.
Tai Shan is a native Washingtonian, born at the National Zoo in 2005.
"My two daughters are very devastated the panda is leaving," Pam Gaston of Stafford, Va., told ABC News. "So they said they had to come and see him before he leaves."
Pam's daughters, Sydney and Lexi, said that Tai Shan was the cutest animal at the zoo and their favorite.
"He's special, he's really cute," Sydney said. "I think it's sad but it's good that he's going back to make more pandas."
Washington Mayor Adrian Fenty once called Tai Shan the city's most important citizen -- a distinguished title given the power brokers that call the District of Columbia home.
His parents, Mei Xiang and Tian Tian, arrived in December 2000 and reside at the zoo as part of a $10 million, 10-year loan from China. The zoo is hoping to start negotiating for an extension this spring to keep the two adult pandas in the United States.
Tai Shan was scheduled to move to China when he turned two in 2007, but China granted the National Zoo two extensions that allowed the animal to remain in Washington three extra years.
The zoo asked if he could stay for another year, but the Chinese said no, that it was time for him to come to China and start to procreate.
The overwhelming consensus this week among panda watchers, adults and children, has been that Tai Shan's departure for China is bittersweet -- sad, of course, because of the loss of the beloved animal, but happy because if he is successful in this next stage of his life, there will be more pandas in the future.
Don Moore, the acting director of the National Zoo, said Tai Shan was like family.
"It's kind of like sending your kid off to college and knowing that your child is going to be a human breeder eventually, too," he said. "We'll miss him, but we know he is going on to something more important, another phase in his life, to get a girlfriend, have babies of his own."
Yasmin Helpeling, an eight-year-old from Bethesda, Md., said she has seen Tai Shan 12 times at the zoo because "they're cool and they're fun to see."
She was taking the imminent departure in stride.
"It's sort of happy because he's really from China. It's OK for him to go back," she told ABC News on Saturday.
"We're all very sad to see him go," said Brandie Smith, senior curator of the Smithsonian National Zoo. "But we're so excited he's going to China to be part of the breeding program and to fill the world with more pandas."
In Atlanta, the reaction was no less melancholy.
"Of course I'm sad," Atlanta zookeeper Heather Roberts told ABC News. "It's our first cub, our first baby, so of course it's hard to see her leave."
Chinese scientists at the China Conservation and Research Center's Wulong Nature Reserve in Sichuan, China, are busy preparing new food and the pandas' new home.
They're even hiring a language tutor to teach the pandas Chinese. Right now, they only respond to words and phrases in English.
But the trainers say the pandas will adapt easily.
The Chinese are hoping the pandas will reproduce. To improve the odds, Mei Lan has her pick of boyfriends. Chinese citizens actually are voting for the suitors online.
On one Web site, each bear has its own video and dreamy music. One of them is named "Superman Kobe," and another, "Handsome Yong Yong."
America's fascination with pandas began in 1972, when the Chinese sent President Nixon and the first lady two pandas as a gift, after their historic visit to China. Americans loved the animals, and the phrase "panda diplomacy" was born.
"The giant pandas are the most adorable," Pat Nixon cooed.
Conservationists estimate that there are currently only 1,600 pandas remaining in the wild worldwide and about 200 in captivity. Only three other zoos in the United States have giant pandas -- San Diego, Atlanta and Memphis.
Tai Shan and Mei Lan are now on a mission to save their species -- important work that many wish they could have done here.
ABC News' Stephanie Sy and John Hendren contributed to this report.