U.S.-born male giant panda Bei Bei is seen at the Smithsonian's National Zoo in Washington D.C., the United States, on Nov. 11, 2019. A weeklong farewell party for U.S.-born male giant panda Bei Bei, who is to depart the Smithsonian's National Zoo for China later this month, kicked off here on Monday. Bei Bei's departure, scheduled for Nov. 19, is part of the U.S. national zoo's cooperative breeding agreement with the China Wildlife Conservation Association that all cubs born here shall move to China after the fourth birthday. Bei Bei turned four on Aug. 22. (Photos: Xinhua/Liu Jie)

U.S.-born male giant panda Bei Bei is seen at the Smithsonian's National Zoo in Washington D.C., the United States, on Nov. 11, 2019. A weeklong farewell party for U.S.-born male giant panda Bei Bei, who is to depart the Smithsonian's National Zoo for China later this month, kicked off here on Monday. Bei Bei's departure, scheduled for Nov. 19, is part of the U.S. national zoo's cooperative breeding agreement with the China Wildlife Conservation Association that all cubs born here shall move to China after the fourth birthday. Bei Bei turned four on Aug. 22.

U.S.-born male giant panda Bei Bei is seen at the Smithsonian's National Zoo in Washington D.C., the United States, on Nov. 11, 2019. A weeklong farewell party for U.S.-born male giant panda Bei Bei, who is to depart the Smithsonian's National Zoo for China later this month, kicked off here on Monday. Bei Bei's departure, scheduled for Nov. 19, is part of the U.S. national zoo's cooperative breeding agreement with the China Wildlife Conservation Association that all cubs born here shall move to China after the fourth birthday. Bei Bei turned four on Aug. 22.

U.S.-born male giant panda Bei Bei is seen at the Smithsonian's National Zoo in Washington D.C., the United States, on Nov. 11, 2019. A weeklong farewell party for U.S.-born male giant panda Bei Bei, who is to depart the Smithsonian's National Zoo for China later this month, kicked off here on Monday. Bei Bei's departure, scheduled for Nov. 19, is part of the U.S. national zoo's cooperative breeding agreement with the China Wildlife Conservation Association that all cubs born here shall move to China after the fourth birthday. Bei Bei turned four on Aug. 22.

U.S.-born male giant panda Bei Bei is seen at the Smithsonian's National Zoo in Washington D.C., the United States, on Nov. 11, 2019. A weeklong farewell party for U.S.-born male giant panda Bei Bei, who is to depart the Smithsonian's National Zoo for China later this month, kicked off here on Monday. Bei Bei's departure, scheduled for Nov. 19, is part of the U.S. national zoo's cooperative breeding agreement with the China Wildlife Conservation Association that all cubs born here shall move to China after the fourth birthday. Bei Bei turned four on Aug. 22.

U.S.-born male giant panda Bei Bei is seen at the Smithsonian's National Zoo in Washington D.C., the United States, on Nov. 11, 2019. A weeklong farewell party for U.S.-born male giant panda Bei Bei, who is to depart the Smithsonian's National Zoo for China later this month, kicked off here on Monday. Bei Bei's departure, scheduled for Nov. 19, is part of the U.S. national zoo's cooperative breeding agreement with the China Wildlife Conservation Association that all cubs born here shall move to China after the fourth birthday. Bei Bei turned four on Aug. 22.

U.S.-born male giant panda Bei Bei is seen at the Smithsonian's National Zoo in Washington D.C., the United States, on Nov. 11, 2019. A weeklong farewell party for U.S.-born male giant panda Bei Bei, who is to depart the Smithsonian's National Zoo for China later this month, kicked off here on Monday. Bei Bei's departure, scheduled for Nov. 19, is part of the U.S. national zoo's cooperative breeding agreement with the China Wildlife Conservation Association that all cubs born here shall move to China after the fourth birthday. Bei Bei turned four on Aug. 22.

U.S.-born male giant panda Bei Bei is seen at the Smithsonian's National Zoo in Washington D.C., the United States, on Nov. 11, 2019. A weeklong farewell party for U.S.-born male giant panda Bei Bei, who is to depart the Smithsonian's National Zoo for China later this month, kicked off here on Monday. Bei Bei's departure, scheduled for Nov. 19, is part of the U.S. national zoo's cooperative breeding agreement with the China Wildlife Conservation Association that all cubs born here shall move to China after the fourth birthday. Bei Bei turned four on Aug. 22.