Less than three-fourths of an inch long, mayflies come from eggs laid in river water in the thousands. After a few days, the larvae hatch. Buried in the bottom of the riverbed, they molt again and again, shedding their skins up to 30 times.

One to three years later, they’re finally ready to go. The larvae float to the water’s surface and burst into flight. They spend brief lives as flighted insects mating and dropping eggs in water. After just a day or two, they die — the shortest life span of any animal.

About 3,000 species of mayfly live around the world. You can find them in the United States, too — if you’re quick enough to catch them on the wing.