At dinner in Beijing in Feb. 1972, First Lady Patricia Nixon mentioned her fondness for giant pandas to Chinese Premier Zhou Enlai. Eager for better relations with the U.S., Zhou knew just what to say: "I'll give you some." On April 16, 1972, President and Mrs. Nixon formally welcomed giant pandas Ling-Ling (a female) and Hsing-Hsing (a male) to the Smithsonian's National Zoo. Over the next 20 years, Ling-Ling and Hsing-Hsing produced five cubs. Sadly, none of the offspring survived for more than a few days. But ever since their arrival, the pandas have symbolized cross-cultural collaboration between the United States and China.

The arrival of giant pandas drew millions of fans from around the world to the Zoo. More importantly, it gave the Zoo an unparalleled opportunity to study giant panda behavior, health and reproduction. Specifically, it allowed scientists at the Smithsonian Conservation Biology Institute to learn about panda estrus, breeding, pregnancy, pseudopregnancy and cub development. Armed with this knowledge, the Zoo became a leader in giant panda conservation and shared the information learned with other institutions that wanted to care for and breed this endangered species.

On Dec. 6, 2000, giant pandas Mei Xiang and Tian Tian arrived at the Zoo. Unlike Ling-Ling and Hsing-Hsing, however, the Zoo's second pair of pandas are on loan. In exchange, the Zoo contributes funds and expertise toward conservation efforts in China. The Zoo reached an agreement with the Chinese government, stipulating that the pair could live at the Zoo for 10 years in exchange for $10 million. On Jan. 20, 2011, Zoo Director Dennis Kelly and Secretary General of the China Wildlife Conservation Association Zang Chunlin signed a new Giant Panda Cooperative Research and Breeding Agreement, which stipulated that giant pandas Mei Xiang and Tian Tian would remain at the Zoo until Dec. 15, 2015.

Giant pandas will continue to live at the Zoo through the end of 2020. The breeding agreement signed by Zoo Director Dennis Kelly and Li Qingwen, deputy secretary general of the China Wildlife and Conservation Association (CWCA), will take effect Dec. 7, 2015, through Dec. 7, 2020.

In Dec. 2011, David M. Rubenstein donated $4.5 million to the Zoo to fund the giant panda program through 2016. In appreciation, the giant panda complex -- home to giant pandas Tian Tian (male) and Mei Xiang (female) -- was named the David M. Rubenstein Family Giant Panda Habitat. In addition, young conservation biologists in the U.S. and in China who were awarded Zoo fellowships for their work to save this endangered species were named "David M. Rubenstein Fellows." The gift was used to fund conservation efforts in China, reproductive science, professional training programs, giant panda care at the Zoo, upgrades to the Zoo habitats and public education. Mr. Rubenstein provided an additional $4.5 million donation in fall 2015 to support the program through 2020.

The gift allows the Zoo to expand its educational outreach efforts and the Zoo's animal care and the Smithsonian Conservation Biology Institute's scientific team to proceed with the five-year science plan established with their Chinese colleagues from the China Wildlife Conservation Association. The science plan has specific goals: to examine the creation and impact of corridors to link fragmented habitats that will benefit giant pandas and other wildlife species, including promoting genetic diversity; examine how to restore habitats, especially those where pandas appear to be making a comeback; provide advice on giant panda reintroduction; examine the potential impact of transmissible diseases on giant pandas and other wildlife species, including providing advice on implementing new programs associated with a Wildlife Disease Control Center being built in Sichuan Province; and continue research on giant panda reproduction and management, because, although there has been major success in Chinese breeding centers, some pandas still experience reproductive challenges.

Giant Panda at the Smithsonian's National Zoo Timeline

1972: Ling-Ling and Hsing-Hsing (shing-shing), the Smithsonian's National Zoo's first pair of giant pandas, arrived from China in April as a gift to the American people to commemorate President Nixon's historic visit to China.

During their 20 years together at the National Zoo, this panda pair produced five cubs; none of the cubs survived.

1983: After a decade of trial and error, Ling-Ling and Hsing-Hsing mated for the first time. Ling-Ling was also artificially inseminated with semen from Chia-Chia (cha cha), a giant panda in London. On July 21, Ling-Ling gave birth to a male cub that died three hours later of pneumonia. Using DNA analysis, Smithsonian Conservation Biology Institute scientists determined the cub was Hsing-Hsing's.

1984 – 1989: The pair went on to produce four more cubs during this time. One cub was stillborn in 1984. Twins were born in 1987 -- one died quickly from a lack of oxygen and the other succumbed to an infection four days later. The last cub, born in 1989, died of pneumonia 23 hours after birth.

1983 – 1991: In addition to the five pregnancies, Ling-Ling also experienced many pseudopregnancies.

1992: Ling-Ling died Dec. 30, of heart failure; she was 23.

1999: Hsing-Hsing, suffering from several debilitating, age-related diseases, including terminal kidney disease, was euthanized Nov. 28, 1999; he was 28.

2000: The National Zoo's second pair of giant pandas, Mei Xiang (may-SHONG) and Tian Tian (tee-YEN tee-YEN), arrived in Washington, D.C., on Dec. 6. An agreement reached with the Chinese government stipulated that the pair would live at the Smithsonian's National Zoo for 10 years in exchange for $10 million. Funds were raised from private donors, including lead corporate sponsor Fujifilm and exclusive media partner Animal Planet.

2003: Mei Xiang and Tian Tian attempted to mate but were unsuccessful.

2004: SCBI scientists vaginally inseminated Mei Xiang with Tian Tian's sperm during a non-anesthesia procedure after attempts at natural breeding were unsuccessful. Mei Xiang had a pseudopregnancy.

2005: SCBI scientists and National Zoo veterinarians artificially inseminated Mei Xiang March 11, after it was determined that no successful natural breeding occurred between the pandas during the previous 24 hours. Mei Xiang gave birth to the Zoo's first surviving giant panda cub, Tai Shan, July 9, at 3:41 a.m.

2007: SCBI scientists and National Zoo veterinarians performed two artificial inseminations on Mei Xiang April 4 and 5. The procedures used semen collected from Gao Gao, the adult male at the San Diego Zoo. The procedures were unsuccessful and Mei Xiang had a pseudopregnancy.

2008: National Zoo scientists and veterinarians performed an artificial insemination on Mei Xiang March 19, using fresh semen from Tian Tian. The procedures were unsuccessful and it is believed that Mei Xiang experienced either a pseudopregnancy or the loss of a developing fetus.

2009: SCBI scientists artificially inseminated Mei Xiang Jan. 17, using a very good quality semen sample from Tian Tian. The procedures were unsuccessful and Mei Xiang had a pseudopregnancy.

2010: SCBI scientists artificially inseminated Mei Xiang Jan. 9 and 10, using semen from Tian Tian. Mei Xiang had a pseudopregnancy.

Tai Shan, the only surviving giant panda cub born at the National Zoo, left for Wolong Nature Reserve, China, Feb. 4, to participate in breeding research.

2011: Dennis Kelly, director of the Smithsonian's National Zoo, and Zang Chunlin, secretary general of the China Wildlife Conservation Association, signed a new Giant Panda Cooperative Research and Breeding Agreement Jan. 20. The agreement stipulated that giant pandas Mei Xiang and Tian Tian would remain at the Zoo until Dec.15, 2015.

Mei Xiang and Tian Tian's attempts at natural breeding Jan. 29 were unsuccessful. Reproductive experts from China and experts from SCBI performed an artificial insemination with frozen semen collected from Tian Tian in 2005. A second artificial insemination was performed Jan. 30. SCBI scientists confirmed that Mei Xiang had a pseudopregnancy July 21.

The Zoo announced that David M. Rubenstein donated $4.5 million Dec. 19, to fund its giant panda program through the end of 2015. It also announced that if Mei Xiang and Tian Tian failed to produce a cub in the 2012 breeding season, it was possible that both or one of the bears would return to China.

2012: A team of SCBI scientists and Chinese scientists artificially inseminated Mei Xiang April 29 and 30, using semen from Tian Tian collected and frozen in 2005, after attempts at natural breeding were unsuccessful. Mei Xiang gave birth to a cub Sept. 16, at 10:46 p.m. The cub died Sept. 23. Necropsy results revealed that the cub was a female and she had under-developed lungs, which resulted in liver damage.

2013: Mei Xiang and Tian Tian attempted to mate March 29, but were unsuccessful. A team of SCBI scientists and veterinarians, and Chinese scientists performed two artificial inseminations on Mei Xiang March 30. The artificial inseminations used fresh semen and frozen semen from Tian Tian collected in 2003, and frozen semen collected in 2003 from the San Diego Zoo's panda Gao Gao. Mei Xiang gave birth to Bao Bao Aug. 23 at 5:32 p.m. Mei Xiang gave birth to a second stillborn cub 26 hours later, but the cub was never viable. DNA analysis confirmed that Bao Bao was sired by Tian Tian.

2015: Mei Xiang was artificially inseminated April 26 and 27. Both procedures used frozen semen from Hui Hui (hWEI-hWEI), a 10 year-old panda living in China, and fresh semen collected from Tian Tian. Veterinarians saw a fetus on an ultrasound Aug. 19. Mei Xiang gave birth to two male cubs Aug. 22, at 5:35 p.m. and 10:07 p.m. The smaller of the two cubs died Aug. 26. Zoo pathologists and veterinarians determined that complications associated with aspiration of food material into the cub's respiratory system resulted in the development of pneumonia.

On Sept. 25, 2015 the First Lady of the United States and the First Lady of the People's Republic of China named the cub Bei Bei.

2017: Mei Xiang's second surviving cub, Bao Bao, departed for China on Feb. 21, 2017.

2019: On Feb. 23, 2019, the Zoo and the Embassy of the People’s Republic of China hosted a housewarming to celebrate the new exhibit for visitors inside the panda house. The interactive exhibit highlights the ecology, history, reproduction, conservation and care of giant pandas through a series of games and activities

2019: Mei Xiang's third surviving cub, Bei Bei, departed for China on Nov. 19, 2019.