The leap starts with listening. Before a red fox plunges headfirst into snow, it attends to faint rustles and movements from rodents concealed below, using sound to locate a meal that sight cannot reveal. Blindness is no disqualification. What looks like a reckless dive is the visible finish of an otherwise largely invisible act of measurement.
Two ears beat one. Through binaural hearing, a fox can compare signals reaching either side of its head, drawing directional information from interaural time differences and interaural level differences: tiny disparities in arrival time and loudness. Its ears are adjustable. Their movements help collect sound, while changes in head position provide additional listening perspectives that can help narrow the source's location beneath an uneven, sound-altering layer of snow. Snow complicates the calculation. Because its structure affects how sound travels, the fox must work with a filtered signal rather than an unobstructed view.
The pause earns its keep. A fox may stand still and tilt its head before springing, gathering acoustic information while avoiding the noise its own footsteps would add to the rodent's faint movements. Then listening becomes motion. Pushing off with its hind legs, it arches upward and drives its muzzle and forequarters into the snow, attempting to intercept the animal at the position its hearing has indicated. Success is not guaranteed. The rodent can move, and the snow can resist penetration, so an apparently exact strike remains a wager rather than proof of perfect sensory accuracy. Above, the snow closes.
