Aim: Eat as many moths as you can by tapping or clicking on them. Move your pointer over the bark to aim. Click a moth to swoop in and eat it. Uneaten moths will reproduce and pass on their genes — and color traits — to the next generation.

To begin: Choose an environment below. Repeat the game in the alternative environment and compare your results.

Each additional round creates the next generation of moths based on the proportions of surviving light and dark forms. Each generation lasts 20 seconds and the moths get faster.