After an 8,000-mile journey from China, Washington’s two new giant pandas landed at Dulles International Airport on Tuesday to continue a conservation program at the National Zoo that goes back more than half a century.

Just under a year after D.C.’s last giant pandas left for China, Qing Bao, a 3-year-old year-old female, and Bao Li, a 3-year-old male, arrived in Virginia about 10:30 a.m. Tuesday. They traveled from Chengdu, China, and made a stop in Anchorage.

The zoo is closed Tuesday so the animals can get settled into their new lodgings. Though it will be at least several weeks before visitors will have a chance to see the bears, panda fans were already gearing up.

“I am so excited,” Susan Barba of San Leandro, Calif., said in an email after she learned the pandas were coming. “My sister and I as well as two of our friends are planning a trip to D.C. in February to see them.”

“Our love of the pandas go back to when we saw [earlier giant pandas] Ling Ling and Hsing Hsing as children,” she said. “And I must say even though it was 45 years ago when we first saw them, the excitement and joy has never changed.”

The pandas will be quarantined in the panda house for a minimum of 30 days to reduce the risk of introducing parasites or disease to other animals. Then they’ll have more quiet time to get used to their new habitat.

Their public debut will take place when the zoo believes they are ready to greet the masses.

“During quarantine, they’re going to get to know their keepers. And they’re going to get settled into their routine,” zoo spokeswoman Jennifer Zoon said in a recent interview at the zoo.

“A lot of the work that our giant panda team does with them is training - training different behaviors for … everyday care and medical training,” she said. “That’s all going to be part of the acclimation process, and building that relationship with their keepers.”

By prior agreement, the zoo’s most recent giant panda residents - Mei Xiang, a 26-year-old female; Tian Tian, a 27-year-old male; and their offspring, Xiao Qi Ji, a 4-year-old male - left for China last Nov. 8.

“It’s been a long year without pandas,” veteran giant panda keeper Laurie Thompson, who traveled to China to help with the handover of the new bears, said recently.

“We’re excited,” she said in an interview before she traveled. “We’re ready to meet them and see how they are, compared to our last guys. It was sad to see them go, and it’s not the same without them. But we’ll be excited to see the new guys and we’ll fall in love with them.”

The animals arrived on a white and blue FedEx Boeing 777 “Panda Express” cargo jet adorned with an image of a giant panda on its nose.

Zoo director Brandie Smith also flew to China this month, along with Thompson, keepers Mariel Lally and Trish Jarvis, and zoo veterinarian James Steeil, to attend the handover and get acquainted with the bears.

The idea was to talk to Chinese keepers, let the pandas start to hear the voices of the Americans, and begin to trust their new keepers.

“It takes time,” Thompson said.

The new arrivals signal a renewal of the National Zoo’s 50-year-long project to conserve, study and exhibit giant pandas. They come after concern in the past few years that the program might be in jeopardy, in part because of poor relations between the United States and China.

Over the years, the zoo has added four giant panda cubs to the global population, and has taken care of four adult animals.

In 2016, the International Union for Conservation of Nature announced that the giant panda’s status had improved to “vulnerable” from “endangered” on the list of species at risk of extinction.

As few as 1,864 giant pandas live in the wild, the zoo says on its website. Another 600 live in zoos and breeding centers around the world.

China owns and leases all giant pandas in U.S. zoos, and has agreements that require the animals and their cubs to go to China after their tenure is up. The new pandas are coming on a 10-year lease, ending in April 2034, during which the zoo will pay the China Wildlife and Conservation Association $1 million a year, the zoo has said.

The zoo’s giant panda program began in 1972 with a dramatic Cold War meeting between President Richard M. Nixon and China’s Communist Party Chairman Mao Zedong.

During the visit, first lady Pat Nixon was sitting beside Chinese Premier Zhou Enlai at a banquet in Beijing when Zhou offered the United States a gift of two giant pandas.

Those two - Ling Ling, a female, and Hsing Hsing, a male - arrived that year. They lived at the zoo for 20 years, launching the pandamania that has continued ever since.

Hadley Green contributed to this report.

previous coverage

• The pandas are coming! The pandas are coming!
• DC National Zoo’s giant pandas leave for China, ending an era for animal lovers
• Panda Palooza left D.C. Now it’s Zoo Atlanta’s turn.