A larva is an early stage in the life of certain animals, when they look and act completely different from how they'll appear as adults. A caterpillar is the larva of a butterfly or moth. A tadpole is the larval stage of a frog. A maggot is the larva of a fly.

During the larval stage, these creatures are focused almost entirely on eating and growing. A caterpillar munches leaves all day, storing energy for its transformation. It doesn't look anything like the butterfly it will become: no wings, different body shape, different way of moving.

The transformation from larva to adult happens during a stage called metamorphosis. The caterpillar forms a chrysalis, the tadpole gradually grows legs and loses its tail, and eventually each emerges as something remarkably different. Scientists believe this two-stage life allows these animals to specialize: the larva is built for eating and growing in one environment (like underwater or on a leaf), while the adult is built for moving around and reproducing in another.

The plural of larva is larvae, pronounced “LAR-vee.” Many insects, amphibians, and sea creatures go through a larval stage, making it one of nature's most common life strategies.