Breeding season runs from March to June. Males gather in breeding pools on warm sunny days and float on the top of the water and call out with a low grunting snore-like sound to attract females. The female lays a mass of as many as 5,000 eggs in still, warm, shallow water. The eggs are usually attached to vegetation and hatch in about 9 days. The tadpoles begin to change into frogs in the late summer. The northern leopard frog hibernates in the mud of pond and stream bottoms in the winter. They hibernate in water that will not completely freeze over in the winter. They usually live to about 3 years.