Humpback Whale

ScienceDaily (Nov. 24, 2009) — Rocket science is opening new doors to understanding how sounds associated with Navy sonar might affect the hearing of a marine mammal — or if they hear it at all.

The same type of large industrial sized X-ray scanners that NASA uses to detect flaws in the space shuttle's behemoth solid fuel rockets is now allowing Navy scientists to peek inside the giant head of a whale. The scans are providing detailed three-dimensional replicas of a whale's hearing anatomy using a breakthrough method developed by Dr. Ted Cranford, a marine biologist sponsored by the Office of Naval Research (ONR) and the Chief of Naval Operations Environmental Readiness Division (N45).

Using a simulated model of a male beaked whale's head, Cranford's team at San Diego State University and the University of California at San Diego (UCSD) has unveiled data that suggests mid-frequency active sonar sounds are largely filtered, or "muffled," before reaching the animal's ears. The findings also suggest that higher frequencies used by whales to hunt prey are heard at amplified levels without any dampening.

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