Why Thousands of Spiders Are Crawling in the Skies Over Brazil

And no sleep will be had by me tonight:

Last week, spiders descended in droves upon a town in southern Brazil — literally.

When 20-year-old web designer Erick Reis left a friend’s house on Sunday, he saw what looked like thousands of spiders overhead, reported G1, a Brazilian news site, on Feb. 8. The large, sturdy spiders were hanging from power lines and poles, and crawling around on a vast network of silk strands spun over the town of Santo Antonio da Platina.

Reis did what many of us might do: He pulled out his camera and shot a video of spiders seemingly falling from the sky.

As creeptastic is it may be, “The phenomenon observed is not really surprising,” said Leticia Aviles, who studies social spiders at the University of British Columbia. “Either social or colonial spiders may occur in large aggregations, as the one shown in the video.” The reason, she and others say, is simple: This is how they hunt.