Hunting spiders can not only watch your every move, but they can feel those moves, and that of their prey, through the air. How their tiny specialized hairs do it has puzzled researchers for decades, but one team of scientists may have found a break. Their physics-focused work suggests each hair acts like a single, independent ear — not a network of ear parts that, together, turn a spider’s exoskeleton into one giant ear, as was previously assumed.