WASHINGTON D.C. (The Hill) — The National Zoo’s three giant pandas departed Washington, D.C. on Wednesday morning, marking the beginning of their trip back to China and an end, at least for now, to 50 years of “panda diplomacy” with Beijing.

Giant pandas Mei Xiang and Tian Tian and their cub Xioa Qi Ji were loaded into crates Wednesday morning by zoo and FedEx staff, and then brought to Dulles International Airport in northern Virginia. The pandas will be transported on the custom-designed “FedEx Panda Express” Boeing 777F aircraft for the 19-hour journey with a stopover in Alaska.

The pandas’ departure follows a series of other pandas being pulled from multiple Western zoos as agreements expire, with some foreign policy experts noting it could be indicative of growing diplomatic tensions between Beijing and several Western governments. 

But zoo officials say it was simply time for the panda parents to go home, with a three-year extension to their stay set to expire. Mei Xiang is 25 and Tian Tian 26.

Here’s what we know about the pandas’ departure and what this might mean for the future of pandas in the U.S: 

Why are the pandas going back to China? 

Mei Xiang and Tian Tian have been at the National Zoo since 2000 as part of the zoo’s Giant Panda Cooperative Research and Breeding agreement with the China Wildfire Conservation Association. The deal was initially supposed to last 10 years, but was renewed three times since 2010. 

The National Zoo announced earlier this year the agreement, set to end on Dec. 7, 2023, would not be renewed for a fourth time. The Hill has reached out to zoo officials for details on why the agreement wasn’t extended again, or why the pandas headed back a month earlier than initially expected. The pandas were slated to be brought back to China in early December.

The plane carrying the pandas is slated to take off from Dulles at 1 p.m. en route to Anchorage, Alaska, where the crew will refuel and continue onto Chengdu, China, the zoo said Wednesday.  

A flight listed on FlightAware that appears to match the itinerary provided by the zoo shows the pandas arriving in Alaska around 5:05 p.m. EST. The plane is expected to depart around 6:45 p.m. and travel over 10 hours to Chengdu Shuangliu International Airport.

Once in Chengdu, the pandas will be greeted by new keeps from the China Conservation and Research Center for The Giant Panada and brought to Wolong, where they will quarantine for about 30 days, the zoo said. 

What’s the history of “panda diplomacy” between U.S. and China? 

The United States’s so-called “panda diplomacy” with China began under an agreement brokered by former President Nixon in 1972.

According to the National Zoo, first lady Patricia Nixon discussed her “fondness” for giant pandas to Chinese Premier Zhou Enlai at a dinner in Beijing in 1971. Premier Enlai then gifted two giant pandas to America, which Nixon and his wife chose to house in the National Zoo.

The two pandas, Ling-Ling and Hsing-Hsing, went on to spend 20 years together at the zoo, which worked with China to study the animals’ biology, behavior and diseases.

The partnership was part of China’s efforts to preserve the species, which were on the endangered species list for more than 25 years until 2016, when the International Union for Conservation of Nature downgraded the species’ status to “vulnerable.” It was not until 2021 that Chinese officials announced they had also reclassified the specifies as vulnerable. 

Minister Xu Xueyuan from the Embassy of the People’s Republic of China said on Wednesday that the partnership has “contributed strongly the mutual understanding and friendship between the Chinese and American peoples.” 

“As a diplomat in Washington, I say to them, goodbye and bon voyage,” Xu said. “As a Chinese government official, I say welcome back.” 

Xu said China will continue to work with its “cooperation partners,” including the United States. 

“As this chapter of our giant panda program closes, we remain committed to the conservation of this species and look forward to continued collaboration with our Chinese colleagues,” National Zoo director Brandi Smith told reporters on Wednesday. 

Will pandas ever come back to the National Zoo? 

The National Zoo on Wednesday hinted at a potential return of the giant pandas.

“It’s a moment of joy because this is one more step in 50 years of a successful giant panda conservation program, and hopefully the beginning of 50 more years,” Smith said. “Please know the future is bright for giant pandas. We remain committed to our program, and we look forward to celebrating with all of you when pandas can return to D.C.”

Beijing lends out 65 pandas to 19 countries through “cooperative research programs,” that aim to protect the species, according to The Associated Press. The pandas typically are returned to China when they reach old age, or when cubs born abroad turn around age 3 or 4.  

The pandas’ departure from the National Zoo comes amid a trend being seen at other zoos across the country. The San Diego zoo returned its pandas in 2019 while the last bear at the Memphis, Tennessee zoo returned to China earlier this year, per The AP. 

This means the only giant pandas left in America are at the Atlanta Zoo, though that loan agreement expires late next year. 

Is the pandas’ departure a message from China? 

Some foreign policy experts have suggested the increasing departures of pandas from the U.S. could be reflective of the rising tensions between Beijing and some Western governments. 

Dennis Wilder, a senior fellow at Georgetown University’s Initiative for U.S.-China Dialogue on Global Issues, told The AP the pattern can be called “punitive panda diplomacy.” Wilder pointed to zoos in Scotland and Australia, which are also experiencing departures with little sign of renewed loan agreements. 

Wilder told The AP the Chinese could potentially be “trying to send a signal,” pointing to a series of enflamed tensions between the U.S. and China in recent years.

These include U.S. government’s sanctions on Chinese citizens and officials, restricted import of Chinese semiconductors, and tensions over the Chinese-owned social media platform TikTok. 

However, both sides have recently signaled an easing of those tensions, and President Biden and Chinese President Xi Jinping appear set to meet in California later this month.