Study
The monopulsed nature of sperm whale clicks
Møhl, Bertel; Wahlberg, Magnus; Madsen, Peter T.; Heerfordt, Anders; Lund, Anders
The Journal of the Acoustical Society of America, 2003
A large hydrophone array was used to record sperm whale clicks from known positions and orientations, so that source level and directionality could be measured rather than estimated from a single receiver at unknown range.
- Studied in
- Physeter macrocephalus
- Sample size
- clicks recorded on a large-aperture hydrophone array
On-axis clicks are highly directional and reach source levels around 230 decibels re 1 micropascal at 1 metre, among the loudest sounds produced by any animal. The click is a single sharp pulse when measured on the beam axis; the multi-pulse structure reported previously is an off-axis artefact of the sound path through the head.
What it means
The authors' reading, and ours. Where they differ, that difference is the point.
How the authors put it
The sperm whale click is a highly directional, extremely powerful monopulse, produced by a nasal complex functioning as a sound generator and beam-former.
How NatureHQ reads it
This measurement is the origin of the claim that sperm whale clicks could kill a person, and it does not support it. The decibel figure is real and enormous — but underwater decibels use a different reference pressure from the airborne scale people know, and the same acoustic energy expressed on the airborne scale is around 62 units lower. The number is also on-axis, at one metre, from an animal that beams its sound forwards to find squid. There is no documented case of a person harmed by sperm whale sonar, and divers work around these animals. The interesting fact — that a nose evolved into a directional sound cannon — needs no help from the invented one.
- On-axis measurements require the whale to be pointing at the array, which biases which clicks are captured.
- Source level at one metre is a convention; no receiver is ever at one metre.
- Effects on other organisms were not studied here and cannot be inferred from source level alone.
Measuring the loudest animal sound without guessing the distance
How loud is a sperm whale click really, and what shape is it?
What this study is used for on NatureHQ
One study can inform several subjects. Here is everywhere this one is cited.
Published by: University press journalsPublished in a university press journal.
This reference was resolved automatically against Crossref on 2026-08-11.
NatureHQ summarises research in its own words and does not reproduce published text. Reviewed 2026-08-11.