The last American pandas are expected to leave Atlanta for China this fall

The last American zoo with pandas in its care hopes to say goodbye to the four giant bears this fall.

Zoo Atlanta is preparing to repatriate panda parents Lun Lun and Yang Yang to China with their U.S.-born twins, Ya Lun and Xi Lun, zoo officials announced Friday.

There is no specific date for the transfer yet, they said, but it is expected to take place between October and December.

The four Atlanta pandas are the latest to be in the United States since the National Zoo in Washington returned three pandas to China last November. Other U.S. zoos returned pandas to China as loan agreements expired due to increased diplomatic tensions between the two countries.

Atlanta received Lun Lun and Yang Yang from China in 1999 as part of a 25-year loan deal that will soon expire.

Ya Lun and Xi Lun, born in 2016, are the youngest of seven pandas born at Zoo Atlanta since their parents arrived. Their siblings are already in the care of the Giant Panda Breeding Research Center in Chengdu, China.

America may welcome a new pair of pandas before the bears leave Atlanta. The San Diego Zoo said last month that staff members recently traveled to China to meet pandas Yun Chuan and Xin Bao, who could arrive in California as early as this summer.

Zoo Atlanta officials said in a news release that they should be able to share “significant notice” before their pandas depart.

As for whether Atlanta could host future pandas, “no discussions have yet taken place with partners in China,” zoo officials said.