The American bullfrog is a highly reproductive aquatic species that is native in the central and eastern United States and southeastern Canada. This species was first introduced to western America as a food source (frog legs!); since then, it escaped aquaculture ponds and has spread widely. Bullfrogs lay up to 20,000 eggs each season and are voracious predators: they eat anything that fits in their mouth. Bullfrogs can be recognized by the large, round eardrums behind their eyes.