One trait that unites all amphibians is that they have relatively permeable skin, and they can breathe and sometimes even drink through it. This leaky skin unfortunately leads them to be especially susceptible to toxins and other environmental stressors. The name 'amphibian', which means 'two lives' in Latin, refers to their double life both in and out of the water.
The typical amphibian life cycle starts in the water with eggs that then hatch into larvae - tadpoles, in the case of frogs - which metamorphose into adult form. The adults can live relatively independently of water for extended periods of time, and in some cases, like the spadefoot toads of the southwestern United States, they can remain underground nearly an entire year without water. But even the spadefoots need to return to water to breed and complete the life cycle.
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