Black widows must despise Clint Sergi. While working on his Ph.D. in biology at the University of Wisconsin-Milwaukee, Sergi spent his time designing little challenges for spiders—which often involved rewarding them with tasty dead crickets or confounding them by stealing the crickets away. “The big question that motivated the work was just wanting to know what is going on inside the minds of animals,” he says.

Biologists already know spider brains aren’t like human brains. Their sensory world is geared for life in webs and dark corners. “Humans are very visual animals,” says Sergi. “These web-building spiders have almost no vision. They have eyes, but they’re mostly good for sensing light and motion.” Instead, he says, a black widow’s perception comes mainly from vibrations, kind of like hearing. “Their legs are sort of like ears that pick up the vibrations through the web.”