The panda is considered a vulnerable species.
As Ying Ying and Pe Pe arrived in Mexico before China changed its policy, Xin Xin and Shuan Shuan will stay in Mexico.
“With that, Mexico became the first country outside of China to have had a successful natural reproduction of pandas outside their natural habitat, in captivity conditions,” said Tinajero.
He said eight more pandas were born in Mexico between 1980 and 1990 but only four of those survived.
Giant pandas typically live until about 20 in the wild and 30 in captivity.
They average around 100-115 kilograms (220-250 pounds) and adults stand between 1.2 to 1.9 meters (4-6 feet) tall. Males can weigh as much as 160 kilograms.
PHOTOS BY ALFREDO ESTRELLA/afp