The National Zoo Celebrates 50 'Exciting' Years of Caring for Pandas

Smithsonian Zoo Pandas — Photo: Smithsonian National Zoo

On April 16, 1972, following President Richard Nixon's historic visit to China to open diplomatic relations, two black and white bears were delivered to the National Zoo in Washington, D.C., in an act of panda diplomacy. Ling-Ling and Hsing-Hsing became the first panda residents of the National Zoo. They quickly wooed Washington crowds, kicking off the zoo's 50-year relationship with the adorable species.

Shortly after Ling-Ling and Hsing-Hsing arrived at the National Zoo, conservationists classified the giant panda as an endangered species. The bear's natural habitat, the bamboo forests of China, was shrinking, and a survey found only 1,000 to 1,100 bears were left in the wild. In the 1980s, it became clear that saving the giant panda from extinction would take a worldwide effort that needed scientists, ecologists, biologists, veterinarians, and specialists in artificial insemination. Thankfully, the panda's sweet, charismatic, and striking appearance made them ideal symbols for wildlife conservation efforts; the species quickly attracted the world's attention and determination.

"It is a true collaboration between China and the U.S., and globally," Janine Brown, who leads the endocrinology lab at the Smithsonian's National Zoo and Conservation Biology Institute, told PEOPLE. "They want their flagship species to survive, and we obviously want it as well. It's really heartwarming to see how hard everybody works to get this done."

Today, because of the cooperation between China's panda experts and zoos worldwide, wild pandas numbers are up, with roughly 1800 giant pandas living in the wild and another 600 in captivity in China and around the world. The Chinese government no longer considers the giant panda as "endangered," reclassifying the species as "vulnerable" in 2021.

Successful zoo and sanctuary programs have led to a healthy captive panda population, some of which have been released into the wild. Almost a dozen pandas in captive care have been successfully set free in China's bamboo forests, and more reintroductions are planned for the future.

"I honestly didn't know that I would ever see that, so as you can imagine, it is extremely exciting. We're just so happy," Brown said.

The task to save the species has been monumental, especially since giant pandas have unusual biological characteristics.

"We've always joked that the panda was almost asking to be extinct because they're so unique," Brown said about the natural challenges facing the bear. Pandas are carnivores that eat mostly bamboo shoots, and females can only get pregnant during a single 24- to 48-hour period each year. That certainly "works against them from a survival standpoint," Brown added.

The National Zoo helped contribute to the successful efforts to bolster wild panda numbers by caring for and closely monitoring the numerous pandas they have housed over the past 50 years, including several baby pandas born at the zoo.

The first set of National Zoo pandas, Ling-Ling and Hsing-Hsing, had five cubs, but none survived. The next panda couple loaned to the Washington D.C. facility from China, Mei Xiang, and Tian Tian, who currently reside at the zoo, got along but never mated naturally.

"It's challenging because they're not really clear behaviorally on when they're the most fertile — other species tend to advertise their fertility status," Brown said of pandas.

After the National Zoo's first panda pair did not successfully reproduce, the zoo found that panda pregnancy would likely have to come through artificial insemination, requiring Brown and a technician to carefully monitor Mei Xiang so they could pinpoint her short window for fertility.

This monitoring includes 24-hour "pee patrol" surveillance for five to seven days each year, where keepers closely watch the female panda's bathroom schedule. Each time Mei Xiang urinates, a technician collects a sample off the floor with a syringe to test the bear's hormone levels. When the zoo detects the bear is just past peak hormone levels, they start moving ahead with artificial insemination.

"It's very, very exciting when we get to that last sample that we can pull the trigger and say, 'now's when you go,'" Brown said of the process. "We're just all a sigh of relief and elated — and then you wait and see what happens."

There is an international "studbook" with details on each breeding panda's DNA to protect against inbreeding. At an annual meeting in China, scientists use an algorithm created by the Smithsonian National Zoo and Conservation Biology Institute to determine which female should reproduce with which male, either naturally or — for animals continents or even generations apart or simply uninterested in each other — by using frozen sperm and artificial insemination.

"You don't just want to have large numbers of animals; you want to have high-quality animals that are very genetically different," Brown explained.

Dr. Pierre Comizzoli, a research veterinarian at the National Zoo specializing in animal reproduction, discovered the techniques used to freeze and thaw giant panda sperm.

"You really want to be successful because you know that you only have one chance per year, and if you fail, after that, the clock is ticking, and then you have to wait another year," Dr. Comizzoli said.

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Through her years at the National Zoo, Brown has become an expert in determining the right time for a panda's insemination. Still, this system does not produce a live cub most years, which she says is common among the zoos trying to breed giant pandas.

Even a live birth doesn't ensure a good outcome. When the cubs are born, they are the size of a stick of butter and weigh less than a pound. At birth, "it's touch and go because they're certainly underdeveloped, their eyes aren't open, they don't have much covering their bodies so they can get cold really quickly, and there have been some abnormalities, not fully formed lungs for example. We had some problems with our first pair of pandas that would get pregnant, and the cubs wouldn't survive — they are a real challenge in every way you look at it," Brown said.

Each time Brown's team succeeded in welcoming a healthy panda cub, the public became utterly smitten with the baby animal, including Tai Shan, Bao Bao, Bei Bei, and Xiao Qi Ji, the "little miracle" born during the pandemic.

"Given the total number of giant pandas that we have right now on the planet, it's a kind of race against time," Comizzoli said. "It's very daunting, but at the same time very exciting. When we are successful, it's highly satisfying because we have really — it's not only an impression — but we feel that we are definitely changing the fate for that species."

Brown shared that the National Zoo recently developed a way to monitor hormone levels from fecal samples, which will allow the zoo's colleagues in China to monitor panda reproduction in the wild.

Mel Songer, a conservation biologist at the National Zoo, is also assisting wild pandas by working with colleagues in China to bring back the country's bamboo forests lost to logging. Songer and her team's efforts have already attracted bears in the wild. She thought it might take ten years to get the attention of wild pandas but was overjoyed when her colleagues sent her a photo of a big pile of panda poop where Songer's team had replanted bamboo.

"I didn't expect it to happen in that timeframe; it was about three to five years after we started the planting," she said. "For a scientist, we don't often see that quick of a return, so it was pretty cool."

She's also working on connecting pockets of the forest that have become disconnected due to roads and agriculture so that wild pandas have more room to roam and more mates to select. The Chinese government now has 67 protected areas for the species and has begun developing Giant Panda National Park.

"I get excited about any species coming off the endangered species list," Songer said, adding that conservationists' success with giant pandas "shows that when we get serious about it and really put the efforts into it, we can do this, we can save a species."

She added that saving the giant panda and its habitat simultaneously saves 4,000 known species of plants and animals that live in China's bamboo forests.

"That's the thing about it — when you focus on a single species, you have this whole system that you're protecting, that you're allowing to become in balance as nature would," Songer said.

As elated as the scientists are that the giant panda population has been brought back from the brink, the National Zoo warns that the danger of extinction still lurks.

"We need to be very careful about claiming, 'okay, this is a success; we saved the giant panda.'" Comizzoli cautioned. "We don't want to lower the guard right now. This is very important to continue because if we start to decrease our efforts or switch our attention to something different, you can be sure that the giant panda will be in trouble again. This is a constant effort."

To learn how the National Zoo is celebrating 50 years of panda conservation and working to keep the species safe in the future, visit the National Zoo's website.