Study
The Sonar of Dolphins
Au, Whitlow W. L.
Springer, 1993
A monograph assembling the physics and performance of dolphin echolocation: click production, beam formation, source levels, target discrimination experiments and the acoustics of the head.
- Studied in
- Tursiops truncatus
- Sample size
- monographic synthesis of dolphin biosonar measurement
Dolphins produce short broadband clicks in the nasal passages, focus them through the fatty melon into a narrow forward beam, and receive returning echoes through fat channels in the lower jaw. Trained animals discriminate targets differing slightly in wall thickness or material at distances of tens of metres.
What it means
The authors' reading, and ours. Where they differ, that difference is the point.
How the authors put it
Dolphin biosonar is a high-resolution, actively steerable sensing system whose performance exceeds engineered sonar on several discrimination tasks.
How NatureHQ reads it
The anatomy is the surprising part and it is rarely explained: a dolphin does not hear through its ears in any ordinary sense. Sound enters through the lower jaw, conducted by specialised fat to the middle ear, and the outgoing click is shaped by a fatty lens in the forehead. Echolocation is also not vision with sound — it returns material and internal structure, which is why a trained dolphin can tell a water-filled cylinder from an oil-filled one.
- Dominated by captive trained bottlenose dolphins performing artificial discrimination tasks.
- Wild echolocation behaviour is far less characterised than laboratory performance.
- Species vary considerably in click structure and frequency.
What this study is used for on NatureHQ
One study can inform several subjects. Here is everywhere this one is cited.
Dolphins
A dolphin hears through its jaw, and its sonar reports what a thing is made of, not just where it is
Echolocation
A toothed whale makes its clicks in its nasal passages, focuses them through a fatty organ in its forehead, and receives the echoes through fat in its lower jaw. Nothing about it works the way a mouth and an ear do.
Published by: Springer journalsPublished in a Springer journal.
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