On Halloween in 1832, the naturalist Charles Darwin was onboard the HMS Beagle. He marveled at spiders that had landed on the ship after floating across huge ocean distances. "I caught some of the Aeronaut spiders which must have come at least 60 miles," he noted in his diary. "How inexplicable is the cause which induces these small insects, as it now appears in both hemispheres, to undertake their aerial excursions."

Small spiders achieve flight by aiming their butts at the sky and releasing tendrils of silk to generate lift. Darwin thought that electricity might be involved when he noticed that spider silk stands seemed to repel each other with electrostatic force, but many scientists assumed that the arachnids, known as "ballooning" spiders, were simply sailing on the wind like a paraglider. The wind power explanation has thus far been unable to account for observations of spiders rapidly launching into the air, even when winds are low, however.