Ears win; a pair tilts. In a burrow, where packed soil returns sound from several surfaces while dimness weakens vision, a rabbit can point its broad pinnae at a scrape, breath, or footfall, making hearing more informative than sight before an intruder reaches view. That motion matters. The animal need not see the source before its brain begins a decision.
The ear earns trust. Each pinna funnels pressure waves into the auditory canal, but its ridges and folds impose direction-dependent spectral filtering, meaning that a rustle from above leaves a frequency pattern unlike one arriving from behind. This is active sensing. Because pinnae can change their aim, the rabbit compares successive filters over fractions of a second when one wall throws back a misleading copy. Location becomes the prize. The gain is not magical amplification; it is a more reliable estimate of a source's direction.
Two ears beat one. Interaural time differences and interaural level differences allow the brain to compare which ear receives a brief sound first and which receives it more strongly; small movements of the head and pinnae add further checks when reflections compete. Echoes can mislead, while low light changes the bargain. Yet a predator's approach may produce a shifting directional trace that reflections cannot perfectly copy. That is its wager. In the dirt-dark chamber, an upright ear is less an ornament than a question asked of the walls.
