Hatchlings of Leptodactylus fuscus can survive up to several weeks in their foam nests. Field observations showed that later-stage tadpoles could survive several days under leaves or rocks if their pool dried out. Laboratory experiments investigated the basis of these different out of water survival capacities and compared them to three other species. Recently hatched groups of tadpoles of L. fuscus on a damp substrate generated foam whose quality varied with the level of hydration of the substrate: at high hydration, the mucus of the foam drew water from the substrate, but at low hydration, water was drawn from the tadpoles. When such tadpoles remained longer in the foam nest, their ability to generate foam declined. Individual recently hatched tadpoles did not make foam out of water but did absorb water from wetter substrates. Later stage tadpoles of L. fuscus survived well out of water for at least six days but lost water gradually to the substrate (the drier, the faster). The dendrobatid Mannophryne trinitatis showed similar out of water survival to L. fuscus, but the leptodactylid Physalaemus pustulosus was much more limited, and the bufonid Bufo beebei had very little out of water survival ability. Tadpoles of L. fuscus lost water to the substrate proportionately more from the gut than from other organs, suggesting some regulatory capacity. Recently hatched tadpoles of L. fuscus showed better water retention when in groups in foam than when single on a damp substrate.