What is the average gestation period of a giant panda?

The average gestation period of a giant panda is about 135 days. Actual pregnancies vary widely, commonly lasting roughly 90 to 180 days, because the fertilized egg can remain unattached in the uterus before implantation.

This delayed implantation helps explain why counting from mating to birth produces such a broad range. Once implantation occurs, fetal development proceeds, but the newborn is still exceptionally small and helpless. A giant panda cub is blind, nearly hairless, and weighs only about 85 to 140 grams at birth.

Giant pandas usually mate during a very short fertile window in spring. Females may give birth to one or two cubs, although a mother generally raises only one in captivity and in most wild observations. The cub remains dependent on milk for months while gradually developing the strength and coordination needed to move and feed independently.

The 135-day figure is an average, not a fixed biological countdown. Pseudopregnancy can also make reproduction difficult to confirm, because females may show pregnancy-like behavior and hormonal changes even when no cub will be born.