Kakadu’s 25 frog species are extremely well adapted to the region’s climatic extremes. Many remain dormant during dry times. At the start of the wet season, when the billabongs and swamps start to fill with water, the night air is filled with the sounds of frogs such as the northern bullfrog and the marbled frog. As the water builds up, frogs and tadpoles have plenty of food, such as algae, vegetation, insects, dragonfly nymphs, and other tadpoles. Not all of Kakadu’s frogs are found in the wetlands: many live in the lowland forests.