Overview
- Researchers from Florida Atlantic University used a drifting underwater speaker, two hydrophones, an anchored boat, and an aerial drone to play pulsed low‑frequency sounds to free‑swimming blacktip sharks in nearshore Florida waters and record their movements.
- The sharks changed course away from the source at distances up to roughly 74 meters, showing they can both detect and localize low‑frequency sounds beyond the acoustic near field.
- Across 165 recorded responses, sharks reacted to test sounds between about 71% and 87% of the time and 118 of those responses occurred in the far field where pressure waves, not just local particle motion, dominate.
- Authors emphasize that ocean trials avoid the echo and reflection problems of tanks and say those wild‑animal experiments were essential to measuring natural hearing and directional responses.
- The team proposes that sharks sense water particle motion via inner‑ear structures because sharks lack gas‑filled swim bladders, and they identify direct physiological tests of that particle‑motion hypothesis as the next key step, with implications for shark behavior and human‑shark encounters.