Pharaoh Cicada Magicicada septendecim

Imagine waiting underground for 17 years before emerging to breed. That's the jaw-dropping reality of these cicadas, which spend nearly two decades developing underground before tunneling up to spend just a few weeks as adults. They're the largest and most northern species of periodical cicadas, ranging from Canada down into the United States. When they finally emerge, thousands blanket the landscape in a synchronized mass emergence.

The sheer scale is staggering—millions or billions can emerge from a single patch of forest, their deafening chorus marking the beginning of summer. This extended underground childhood gives them a huge survival advantage: predators can't sustain themselves on such an unpredictable, widely-spaced food source.