In winter, vernal pools swarm with aquatic life, most smaller than a freckle. Frogs and toads come to mate and lay eggs. From November through March, species race against the clock (and their predators) to grow up, mate and lay eggs before the pools dry up.

Many vernal pool seeds sprout in November with the first winter rains. The seedlings remain less than two inches tall throughout the winter as the pools fill with water, submerging them for weeks or months.