Meng Meng, the Berlin Zoo's female giant panda is expecting twin cubs, zoo authorities announced Monday after an ultrasound examination over the weekend showed developing fetuses. 

"One heartbeat could initially be made out on the ultrasound equipment, and shortly thereafter a second as well," they said. 

The cubs are just 2.5 centimeters long at the moment and still have plenty of growing to do before birth. If all goes well the zoo expects the birth at the end of August, zoo officials said. She was artificially inseminated in March 2024.

Pregnancy still at risky stage

Berlin Zoo veterinarian Franziska Sutter cautioned that the pregnancy was still at a risky phase. 

"Amid all the enthusiasm, we have to realize that this is a very early stage of the pregnancy and that a so-called resorption, or death, of the embryo is still possible at this stage," she said.

Pandas have a very unusual reproductive mechanism for mammals, explained Thomas Hildebrandt, head of reproduction management at the Leibniz Institute for Zoo and Wildlife Research.

In contrast to other mammals, fertilized panda eggs do not implant immediately into the wall of the uterus. The process can last for several months until the favorable external conditions are present. 

The cubs will be the first to be born at the zoo in central Berlin in five years, after Meng Meng last produced twin cubs in 2019.

Last panda babies: Pit and Paule

Meng Meng and male panda Jiao Qing arrived in Berlin as a present from the Chinese government in 2017.

In August 2019, Meng Meng gave birth to Pit and Paule, the first giant pandas born in Germany.

The offspring were flown to China in December 2023, as part of an agreement with the Chinese government. 

Ultrasound scan with Chinese experts

Experts arrived from China on Sunday to assist with the preparations for the ultrasound. Meng Meng was initially uncooperative in submitting to the examination. 

"Despite visible tummy pains, Meng Meng could be induced to come into an upright position to accept the cool ultrasound gel and examination with the probe," Hildebrandt said. 

ch/wmr (dpa, AFP)