Matthew: Do all spiders die with their legs scrunched up in a little ball, or is it just the ones in my house? — Anna, San Diego
Anybody’s dead spiders do that leg thing. When they’re alive, spiders use tiny hydraulic systems to keep their legs out straight. The hydraulics counteract little bundles of flexor muscles that pull their legs in. When a spider croaks, the hydraulic pressure drops, the flexors flex freely, and its legs squinch up into an easy-to-vacuum ball of former arachnid.