The lifespan of frogs varies significantly depending on species and habitat. The oldest frog ever recorded was a European common toad that lived for 40 years. A measurement of skeleton growth in wild mountain yellow-legged frogs had shown that one had lived for roughly 14 years.
The average lifespan of frogs is considerably less than these extreme cases; it is generally agreed that most frogs, if they can survive to adulthood, live between 4 to 15 years in the wild and longer in captivity. Frogs graduate through three forms upon hatching from eggs: the larval or tadpole stage, the metamorphic stage and the adult stage. At all stages of this cycle, they are prey for a wide variety of predators.