When it is time to mate, frogs assemble at a body of water. Males arrive first and call females to the site. In the reproductive act, the male mounts the female and fertilizes the eggs as the female releases them. In some species, the adults then abandon the eggs.
One type of breeding, known as prolonged breeding, involves frogs assembling annually at lakes, streams or ponds. Often, large numbers of frogs migrate back to the bodies of water where they were conceived and became larvae. In such cases, males acquire territories they defend from other males. When croaking to attract females, larger frogs tend to have deeper voices than smaller frogs, and these draw females more easily than younger, smaller frogs. Sometimes, males known as satellites wander without territory and intercept females or take over territories abandoned by exhausted calling males.
Some species are considered explosive breeders and converge on suitable breeding pools when one is found by a male. In these cases, the frogs croak in unison to create a very loud noise. Sometimes conditions may not be right, and frogs may go two to three years without mating.
Once the eggs are fertilized, they float freely, become attached to plants or sink in the water. Tadpoles hatch from the eggs within a few days to a week. Depending upon the species, within a few months to a few years, the tadpoles fully metamorphose into frogs, developing lungs and limbs, losing their tails, and altering their jaws and digestive systems