Why Are Giant Panda Cubs So Small at Birth?

Why Are Giant Panda Cubs So Small At Birth

Giant pandas are an ancient species of mammals, and their reproduction involves a unique physiological phenomenon called delayed implantation. After mating, the fertilized egg does not immediately implant in the uterus. Instead, it remains in a delayed state for 1 to 4 months, with an average delay of about 3.5 months, before it finally implants in the uterus and begins developing into a fetus. Once implantation occurs, the fetus only develops in the mother’s womb for about 1.5 months at most. As a result, giant panda mothers give birth before the fetus is fully developed.

This short gestation period is the reason why newborn giant panda cubs are so small. At birth, they typically measure between 15 and 17 centimeters in length and weigh anywhere from 36 to 296 grams. Their weight is generally only about one-thousandth of the mother’s body weight, making panda cubs notably tiny compared to their adult size.