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Gen 1 · 30s
Hunt the moths. Every catch steers evolution!
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About Peppered Pursuit

Spot and snatch camouflaged peppered moths across generations in this free online natural selection game about industrial melanism and the Kettlewell experiment.

Peppered Pursuit is a free online natural selection game where you play a hungry flycatcher hunting peppered moths on tree bark, the classic Kettlewell experiment rebuilt as an arcade hunt. Each round is one generation. Moths that match the bark are camouflaged and genuinely hard to spot, while mismatched moths pop out and get eaten. The survivors reproduce between rounds and the allele bar at the bottom of the screen tracks the melanic allele's share of the gene pool, so you can watch the population evolve under the pressure of your own fingertips.

Every mechanic maps to real evolutionary biology. Before the industrial revolution, the light typica morph blended into lichen-covered bark while the rare dark carbonaria morph stood out and was picked off. When coal soot killed the lichens and blackened the trees, selection flipped within decades and the melanic form dominated, one of the fastest evolutionary changes ever witnessed in the wild. After clean-air laws let the lichens return, selection reversed again. In game terms, soot clouds and lichen blooms are the shifting environment, your taps are differential predation, speckled mutants are mutation supplying raw material and owl nights switch the target of selection from wing color to behavior, because a predator that hunts by sound only spares the moths that freeze.

This matters because natural selection is the engine behind every adaptation on Earth. Antibiotic resistance in bacteria, pesticide resistance in insects and beak size in Darwin's finches all follow the same math: heritable variation plus differential survival equals evolution. Bernard Kettlewell's mark-release-recapture experiments in 1950s Birmingham and Dorset remain the textbook demonstration that predators alone can reshape a species, and the peppered moth is still the classroom icon of evolution caught in the act.

Key Science Concepts

What You'll Learn

Grade Level: Middle School, High School

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How to play

  1. Aim and Launch Drag back and release to fling your flycatcher. Catch every moth in its flight path.
  2. Mind the Hunger Hunger drains constantly and every launch costs energy. An empty belly ends the run. Tap the gauge for Keen Eyes to reveal hidden moths.
  3. The Forest Changes Ram soot clouds or they darken the bark. Hit lichen blooms to lighten it. Camouflage follows the bark.
  4. Generations Turn Each round is a generation. Survivors reproduce and the allele bar lurches toward the morph you spared.
  5. Night Hunts Every fifth generation an owl hunts by sound and camouflage fails. Grab fluttering moths while the freezers survive.
  6. Mutants and Snacks Speckled mutants are rare jackpots worth catching. Hit a caterpillar for slow-motion Keen Eyes.

Frequently asked questions

Is Peppered Pursuit free to play?
Yes. Peppered Pursuit is completely free to play in your browser. There is no download, install or account needed.
What grade level is Peppered Pursuit for?
Peppered Pursuit is designed for Middle School, High School students and works well as a classroom activity or homework.
Does Peppered Pursuit work on phones and tablets?
Yes. Peppered Pursuit runs in any modern browser on desktop computers, Chromebooks, tablets and phones in landscape mode.

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