US: Giant panda Bei Bei celebrates his 4th birthday at DC's National Zoo Giant panda Bei Bei eats his frozen 4th birthday cake, made of diluted apple and grape juice, fruits and sweet potatoes, at the Smithsonian's National Zoo in Washington, DC. This marks Bei Bei’s last birthday celebration in the US capital as he is set to move to China before the end of the year after turning four years old, according to a US-China breeding agreement between the Smithsonian's National Zoo and the China Wildlife Conservation Association. IMAGES AND SOUNDBITES