An illustration of the physiologically dynamic metamorphosis that boreal toads go through.

The boreal toad life cycle has been linked to changes in their skin bacterial communities. Adults lay eggs in an aquatic habitat, which then hatch into tadpoles. Tadpoles develop into metamorphs and move out of the water, into a largely terrestrial habitat, although they continue to return to the water throughout their lifespan. Metamorphs grow into subadults, which are not reproductively mature for 2–3 years. Once they are reproductively mature, the adults visit pond areas to mate and reproduce during spring and retreat to upland terrestrial habitats to overwinter in underground hibernacula.