This spawning ritual is repeated 15-18 times. Roughly 100 eggs are laid and fertilized. The eggs adhere only to the female's back, possibly due to a cloacal secretion. They do not stick to the male's belly nor to other eggs already on the female's back. In the hours after fertilization, the eggs sink into the female's skin.
Skin grows around the eggs, which become enclosed in a cyst with a horny lid.
During development, the young grow temporary tails, which are apparently used in the uptake of oxygen. After 12-20 weeks, the young emerge as tailless flat frogs shaped like their mothers, except that they are only 2 cm in length. They are, however, fully developed except for bifurcation of the lobes on the fingertips. In the wild, the animals space themselves using calls to communicate location and distance. Pipa pipa are usually quiet and still, resting on each other without disturbances.