Such an astonishing event, although surprising, is quite typical for giant pandas, known for their unpredictable pregnancies. The Hong Kong Special Administrative Region (HKSAR) Government announced on August 15 that Ying Ying, a female giant panda gifted to Hong Kong by the central government, gave birth to twin cubs – a boy and a girl – after nearly five months of pregnancy. Surprisingly, experts were only able to confirm her pregnancy through an ultrasound scan three days before she gave birth on August 11.
Giant pandas are known for being particularly tricky when it comes to “pseudo-pregnancy.” In fact, Ocean Park Hong Kong had not previously announced Ying Ying’s pregnancy for fear of a false alarm.

It’s common for many female giant pandas, especially in July and August, to show signs of pregnancy such as sleeping more, losing their appetite, and becoming less active. Some even produce milk and hold toys or bamboo, treating them as if they were their cubs, mimicking pregnancy. However, confirming whether a female giant panda is genuinely pregnant is a significant challenge.
One of the reasons for this is that the gestation period for female pandas generally ranges between 120 to 150 days, but due to the reproductive strategy of delayed embryo implantation, the length of pregnancy can vary greatly between individuals. The shortest recorded pregnancy lasted just 74 days, while the longest stretched to 324 days. Initial signs of pregnancy in pandas usually appear around three months after conception. Before this, the fertilized egg (embryo) floats in the uterus for days without implanting, making it difficult to distinguish a real pregnancy from a false one.
Another complicating factor is the small size of the fetus and the delayed implantation, making it nearly impossible for staff to detect the pregnancy through ultrasound early on. Experts point out that in most cases, the fetus in a pregnant panda can only be detected about 10 days before delivery. For some pandas, it may not be until just one or two days before giving birth that the staff can definitively confirm the pregnancy.
In Ying Ying’s case, this remarkable sequence of events unfolded within just a few days, demonstrating the unique and challenging nature of giant panda pregnancies.