Top-down acoustic model: click trains, beam geometry, travel-time ranging and pod hunting behaviour.
Each dolphin emits a train of clicks inside a forward cone (beam width). A click travels outward at the real speed of sound in seawater (≈1449 + 4.6·T − 0.055·T² m/s, T = water temperature), reflects off any fish or rock inside the cone, and returns as an echo. The round-trip time is used to compute range (distance = speed × time ⁄ 2), exactly as biological/active sonar works. Dolphins in auto-hunt mode turn toward and chase the strongest recent echo.