Reproduction depends on precipitation and occurs when rain is most abundant. In very rainy regions, the females may lay eggs several times a year.
The female selects a male based on the quality and power of his call. Because there are more males than females, fights between males are frequent.
A male may use his head to try to separate another male that is attached to a female. Males fend off their rivals with aggressive calls and by using their hind legs to push their rival away.
Once the female has chosen her partner, the male climbs onto her back (which is standard amphibian behaviour). He clings firmly on by holding her around the armpits and allows himself to be carried to the egg-laying site.
Like other leaf frogs (Phyllomedusinae), this species reproduces outside the water. The female choses a large leaf overhanging a body of water.
The male and female build their nest together by rolling the leaf into a cone shape. Then, the female lays her eggs and the male fertilizes them. Their mating can last four hours! Up to 2,000 eggs can be laid at a time.
The eggs hatch in about 8 to 14 days. The tadpoles fall into the water, where they continue developing. Wetlands near giant monkey frog nests can contain thousands of tadpoles.
They reach sexual maturity in a few years.