usually lay between 16 and 40 eggs, four to six times each year, at about eight-week intervals. Eggs are guarded from predators—other common coquís and Subulina snails—by the males. The gestation period of coquís is from 17 to 26 days. The maturation period, the time from egg to reproductive coquí, is around eight months. Unlike most frogs, which lay their eggs in water, coquís lay their eggs on palm tree leaves or other terrestrial plants. Abandoned bird nests are also used as nests by E. coqui. The bananaquit, Puerto Rican bullfinch and Puerto Rican tody share nests with the coquí. This method of reproduction allows the coquí to live in forests, mountains and other habitats without direct dependency on water. Since eggs are laid on land, coquís bypass the tadpole stage, proceeding to develop limbs within their eggs, rather than going through a metamorphosis as a larva in water. Thus, a fully independent froglet emerges from the egg, with a small tail that is lost shortly after. This stage of direct development has allowed the coqui to become a successful terrestrial colonizer in tropical areas. Eggs hatch within eight weeks and reach reproductive maturity within one year. The common coqui releases their young from the egg using an egg tooth that the genus Eleutherodactylus forms. Both males and females fight off intruders from their nests by jumping, chasing and sometimes biting. The males are the primary caretakers of the eggs. They offer protection and moist environments through skin contact. They will leave during very dry periods in order to collect more moisture for their offspring. Males begin their mating calls by perching above ground level. The coqui's call (or canto in Spanish) is used both as a way of attracting a mate and to establish a territorial boundary. A coqui may enter another's territory and challenge the incumbent by starting his call, at which point they may engage in a sort of singing duel (which can last for several minutes). The first to falter in keeping up with the cadence is considered the loser and leaves the area without resorting to physical violence. This behavior is consistent across different species (which have distinctive calls), so it is possible to hear a duel where one coqui sings "COQUI" and another "COQUIRIQUI". See also Fauna of Puerto Rico List of amphibians and reptiles of Puerto Rico List of endemic fauna of Puerto