That relaxed windowsill pose is a lie. From a height, a cat is running a quiet spatial audit, turning streets, sofas, and shadows into coordinates inside its head. Vision feeds depth through binocular disparity and optic flow, while the vestibular system in the inner ear reports tilt, acceleration, and head angle, so the view becomes geometry, not scenery.
Predator first, pet second: the brain treats every vantage point as a data harvest for future attack routes and exits. In the hippocampus, place cells fire for specific spots, while entorhinal grid cells lay down a hexagonal metric, fusing what the eyes see with proprioception to maintain a volumetric map even when the cat later moves in darkness or behind furniture.
That map is not static wallpaper; it updates with each tail flick. Micro-adjustments in saccadic eye movements, whisker position, and ear orientation refine edges, distances, and occlusions, so the animal precomputes ballistic paths for a jump or a retreat. When the body finally launches, motor cortex and cerebellum simply read out that prebuilt 3D security plan, as if executing stored code.
